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MicroWorld

MicroWorld

World Model & Quantitative Finance

The first world model architecture designed for quantitative finance:
A new paradigm in quantitative finance that transcends traditional factor mining

第一個為量化金融打造的世界模型架構

超越傳統因子挖掘的量化金融新範式


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Alpha Flow Research · HongJin HE · HKUST / Stanford IHP · July 2026


The MVP — predicting the market's denoised price

Strip the behavioral noise from a price and what remains is the equilibrium — what the asset is worth once every player has played their strategy. That track is what we predict. Not tomorrow's tick: the denoised price, for people who hold for months, not milliseconds.

Denoised equilibrium price — the MVP demo

One command, zero API keys: python demo/denoised_price_2026.py — a synthetic concept demo shaped on the July 2026 memory-sector unwind (SOX −19%, its worst month since 2008):

  • Blue is the product — the equilibrium track P^eq the world model solves for. Black is the market — equilibrium plus a behavioral wedge that inflates as institutions crowd in and LLM-homogenized retail chases the tape.
  • The signal — divergence D_t = P_t/P^eq_t − 1 above threshold while the institutional mean field is rotating out — fires 11 trading days (≈2 weeks) before the unwind accelerates. Retail capitulates at the lows; institutions buy them; the price re-joins its denoised track.
  • Who it serves: mid/long-horizon holders (To-C, retail). Deliberately not intraday or high-frequency traders — at those horizons behavioral noise dominates, and Theorem 1 (the dual Cramér-Rao bound) proves no volume of data can out-model it. At weeks-to-months horizons the equilibrium component dominates, and that is exactly where this model is built to work. (A research signal, not investment advice. The real-data version, under the same no-look-ahead rules as our 2008 hindcast, is experiment E7.)

The real-data check — July 2026, replayed on real prices. We froze the 2008 recipe — weights, threshold, sustain rule unchanged, one disclosed adaptation (funding stress → crowding extension) — and replayed the memory basket (SK Hynix, Samsung, Micron, Western Digital, Seagate, SanDisk; daily closes vendored in the repo, keyless) walk-forward through this month's unwind: python demo/hindcast_memory_2026.py (figure with the receipts, below).

  • Three years, zero alarms — through the 2022 memory bear and the 2023–25 recovery, Λₜ never crossed its threshold once.
  • The first alarm of the entire sample: October 22, 2025 — the AI-memory mania itself. The sector left its stable regime 232 trading days before July 2026 delivered its worst month since 2008 (SK Hynix −55% from its peak, in the vendored data).
  • And the honest other half: after the alarm, the basket rose another +446% before it broke. Basin-exit detection is not crash timing — an unstable crowding regime can keep inflating for months. When it breaks is governed by who is holding the wedge up and when they rotate out — the institutional field κ. That κ-rotation condition is exactly the second half of the MVP signal in the synthetic demo above, and reconstructing it from real 13F/COT positioning is experiment E7.

No "we predicted it" claim — this is a hindcast computed after the event, and the figure says so on its face. What it demonstrates is the division of labor inside one world model: Λₜ tells you the regime is unstable; the divergence D_t with κ-rotation tells you when the instability resolves. The synthetic demo shows the second half working; E7 makes it real.

How the network infers the unwind — agents as neurons, principal couplings, mechanism

How the prediction is made, in one figure — (a) the fully connected agent network: every neuron an agent, and the five highlighted edges the principal couplings — the PCA-like handful of interactions that carry this episode; (b) their loadings; (c) the unwind mechanism those couplings generate: information reaches the informed first (w₁), institutions de-crowd (w₂), momentum pulls retail in (w₃, w₄), market-maker inventory sets the gap risk (w₅), and the wedge collapses onto the equilibrium. Agent-game modeling, a new use of neural networks, and the network's structure — one picture.

What makes this possible? Three breaks with everything else on the market — they are the soul of this MVP:

① Causal attribution — the problem deep learning, reinforcement learning, and factor mining structurally cannot solve. A model trained on price data learns from the residue of decisions, and residue explains nothing — which is why every backtest-born signal dies unexplained. We model the decision-makers: real-world data about the market's real player types — institutions, regulators, retail cohorts — cast as agents with objectives, constraints, and information sets, playing a game on a fully connected network. Today we solve that game in simplified form — a multi-body, multi-dimensional hierarchical mean-field system (Phase 1); the unsimplified form — every agent its own neural network, co-trained — is specified in NNGS and waits for hardware (a lab with two hundred H200s would close the gap — the door is open). Either way, every output decomposes the same way: which agents, which constraint, which coupling. Causal attribution is native here, not post-hoc.

② Information asymmetry is the engine of prediction. Prices move because differently informed players act at different times. The framework models the market's stratified information structure explicitly (state/information.py): each agent type sees only its own filtration, and the model estimates what each type's rational move must be given what it alone can see — so price change is anticipated where it is actually born, in the information gap between players, before it aggregates into the tape. July 2026 was this mechanism in the wild: channel checks reached institutions months before headlines reached retail, and the wedge between those two information sets was the crash mechanics.

③ This is not another "financial agents" product. The current wave of LLM finance agents role-plays a research department — a "portfolio manager", an "analyst", a "risk officer" deliberating over the same public headlines. Cosplay manufactures no information: the retail user still never receives cleaned, high-signal-to-noise data, and as thousands of users run the same agent prompts over the same inputs, whatever edge existed crowds away at exactly the speed every factor before it did. Our agents are not personas — they are structural models of the market's real player types, and what the user receives is the cleaned, high-SNR object itself: the denoised equilibrium price. We did not find structure in the data — we modeled the structure that makes the data ↓

The institutional line runs the same engine in reverse — including a 2008 hindcast whose crisis indicator exited the stable regime 272 trading days before Lehman, on public data with no look-ahead: Two Products, One Engine.

The world model, breathing

MicroWorld global demo — a 2-year simulated market: event operators fire, the universe changes size, the mean field deforms, the Lyapunov indicator warns 22 days before the crash, and the controller de-risks

Two simulated years, every layer of the framework evolving at once — generated entirely by the code in this repo, zero API keys: (A) 9 assets driven by the actual event-operator algebra — including an IPO (n 8→9) and a bankruptcy (n 9→8); (B) the Level-0 cross-market backdrop; (C) the mean field of 400 institutional agents deforming into a forced-liquidation regime; (D) the Lyapunov crisis indicator firing 22 trading days before the crash; (E) the controller automatically de-risking.

python demo/global_demo.py     # reproduce this GIF end-to-end (~2 min, CPU, no keys)

The Story

It started on a Tuesday night in a Stanford basement, with a question three students couldn't put down:

Why does every trading model die the moment it goes live?

The answer isn't better data or bigger networks. Markets aren't datasets — they're games. Prices come from fifty thousand institutions, half a billion retail investors, and thirty central banks strategically reacting to each other — and to every model that dares to predict them. Predict the pattern, and the pattern disappears. The only thing left to model is the players themselves.

Twenty-one days later, this repository is the result: the first open-source world model architecture built for financial markets — one that models the players, not the patterns, so its predictions are designed to survive their own deployment. The mathematics is proven, the code runs on a laptop, and the road to a live system is specified down to individual data files.

This is Alpha Flow's first public artifact. The bet is placed — in public. What happens next depends on who joins.

— Alpha Flow Research · a Stanford basement · July 2026

The longer version — how a world-model skeptic was converted by robots that dream, cars that predict, and a factor zoo that violates first principles — is docs/JOURNEY.md.


Table of Contents

  1. The Problem Nobody Has Solved
  2. The First-Principles Bet — Causality over Correlation
  3. Why This Question Is Urgent — Right Now
  4. What Came Before — And Why It Falls Short
  5. Two Kinds of World Model: Type 1 and Type 2
  6. The Market as a Layered Game — Plumbing and Projection
  7. The E-Game-C Architecture
  8. The Mathematical Framework
  9. The Unified Evolution Equation
  10. The Seven Theorems
  11. Reflexivity — Soros, Formalized
  12. The Agent Taxonomy
  13. Connection to the 2026 Fields Medal
  14. What This Makes Possible
  15. Two Products, One Engine
  16. Data Requirements & Research Roadmap
  17. The 17-Day Notebook Series
  18. Repository Structure
  19. Quick Start
  20. Related Work & Positioning
  21. Project Roadmap — Phase 1 and Phase 2
  22. Star History
  23. Partnerships & Contact
  24. References
  25. Citation

The Problem Nobody Has Solved

Every second, approximately 50,000 institutional players, 500 million retail participants, and 30 central banks are simultaneously making decisions about the same set of assets — each with different information, different timescales, different objectives, and different constraints on each other. The price you observe on your screen is the real-time summary statistic of this entire system, updated every millisecond.

No existing model has captured this faithfully.

Financial markets are not merely complex. They are the most sophisticated multi-level competitive system ever produced by human civilization — one in which the very act of modelling changes what is being modelled. Every hedge fund that discovers a pattern immediately destroys it by trading on it. Every central bank that announces a policy triggers a cascade of strategic responses across all four levels simultaneously.

The core question this work answers:

Is there a complete mathematical theory — analogous to statistical mechanics or kinetic theory — that describes financial markets as what they actually are: a multi-level, multi-timescale, multi-objective game between heterogeneous agents?

The answer is yes. This repository presents that theory, and its engineering implementation.


The First-Principles Bet — Causality over Correlation

Every mainstream quant methodology — factor mining, time-series modelling, feature engineering — rests on one unexamined premise: that historical data will repeat. It will not. Every backtested pattern is a snapshot of a game whose players have since changed their strategies, partly because the pattern was found. That is the Lucas critique with teeth, and it is why the factor zoo decays and deployed models die.

But something does repeat. Not the data — the world that generates the data: institutions with mandates, regulators with rules, incentives that do not change when a signal is published. History does not repeat its prices; it repeats its mechanisms. So the only factors that can carry meaning are the ones derived by going back to the world itself — and this project refuses to model the residue when it can model the generator:

Pattern paradigm (factors, TS-ML) World-model paradigm (this repo)
Object modeled The data the market left behind The market itself: agents, constraints, equilibrium
A "factor" is A correlation that worked in-sample A term in an equilibrium condition, with a mechanism attached
When regimes break Silent failure — nothing to explain with The explanation is the model: which agents, which constraint, which coupling
Deployment Erodes the signal (crowding) Reinforces the signal (equilibria are self-consistent)

Two consequences follow, and they are this project's identity:

  1. Explainability is the direction of inference, not a feature. We do not fit prices and hope for meaning; we model the mechanism and derive what prices must do. Every output is attributable to named agents, named constraints, and an equilibrium condition you can inspect.
  2. The model survives contact with the market. A prediction that is an equilibrium does not evaporate when acted on — being acted on is how equilibria assert themselves.

We did not find structure in the data. We modeled the structure that makes the data. That sentence is the entire difference between this repository and every pattern-mining stack in production today.


Why This Question Is Urgent — Right Now

Three simultaneous forces are breaking the old paradigm faster than at any point in history:

1. Factor alpha has a terminal illness. Average alpha half-life: ~6 years in 1990, ~11 months in 2023. The decay is not a cycle — it is a structural consequence of AI-accelerated crowding. When every fund discovers the same signal within months of each other, the signal disappears before anyone profits. Factor models have no theory of why signals decay; they cannot detect the decay until it is complete.

2. LLMs are homogenizing retail behavior at scale. Five hundred million retail investors are now asking the same three AI assistants the same questions and receiving the same answers. The behavioral noise term $\nu^\eta$ is simultaneously increasing (more retail coordination, larger jumps) and becoming more predictable (the coordination mechanism is now modelable). The old assumption that retail noise is unstructured is obsolete.

3. The Fields Medal just validated the paradigm. In July 2026, Deng Yu (邓煜) received the Fields Medal for proving that N-body Newtonian mechanics converges — as $N\to\infty$ — to the Boltzmann equation. This is the mathematical paradigm we apply to finance: N rational agents converge to a Fokker-Planck-Kolmogorov equation. The FPK equation is the financial Boltzmann equation. Deng Yu's proof establishes the rigorous foundation for this class of large-population convergence results. We stand on that foundation.

The window for building game-theoretic world models is now. The models that survive the next decade will be the ones built on mechanism, not pattern.


What Came Before — And Why It Falls Short

I. Factor Models (CAPM, Fama-French, 600+ documented factors)

Factor alpha decay

The dominant paradigm since the 1960s asks: "What statistical features correlate with future returns?"

The fundamental flaw was identified by Robert Lucas in 1976 — the Lucas Critique [1]: once a statistical relationship is widely adopted, rational agents change their behavior in response, and the relationship disappears. The empirical record confirms this:

  • Average factor alpha half-life: ~6 years in 1990 → ~11 months in 2023
  • Harvey, Liu & Zhu (2016) [2]: of 316 documented factors, most fail to replicate
  • The "factor zoo" collapses as AI allows simultaneous deployment at scale

Factor models have no answer to this. They cannot detect when their own signals are decaying, because they do not model why the signal worked in the first place. They are pattern recognizers pretending to be theories.

II. Machine Learning Approaches (LSTM, Transformer, XGBoost on price data)

ML methods attempt to discover patterns that human researchers missed [3, 4]. Their failure mode is Goodhart's Law: when a measure becomes a target, it ceases to be a good measure. More fundamentally:

  • Correlation ≠ causation: ML models cannot distinguish between signals that will survive agent adaptation and signals that will not
  • Distributional shift: financial markets are non-stationary precisely because agents adapt to predictions — the ML model's own deployment changes the distribution it was trained on
  • No structure: without a theory of why prices move, there is no principled way to know when a model has stopped working

The result: quant funds running identical transformer architectures on the same alternative data produce increasingly correlated returns — until the crowding unwinds catastrophically.

III. Existing Agent-Based and Swarm Models

Several groups have recognized the need to model agents explicitly [30, 31, 32, 33, 34]. The most visible recent example:

MicroFish (Guo Hangjiang, BaiFu Capital, 2024) — 33k GitHub stars, ¥30M investment:

MicroFish applies swarm intelligence algorithms (particle swarm, ant colony optimization) to financial price prediction. It is an impressive engineering achievement and its viral success reflects genuine hunger for mechanistic models. However, it is fundamentally limited as a world model:

Capability MicroFish This Framework
Game theory between agents ❌ Agents do not strategically respond to each other ✅ Nash equilibrium computed explicitly
Multi-level hierarchy ❌ Flat swarm — no market / type / institution / individual structure ✅ Four-level hierarchical MFG (cross-market · type · institution · individual)
Intra-institution competition ❌ No concept of desks competing within a fund ✅ Level 3 MFG: intra-institution Nash between individuals
Event operator algebra ❌ Cannot handle M&A, IPO, rate decisions as structural state changes ✅ Full groupoid algebra (Modes I/II/III, 22 operators)
Mathematical convergence guarantee ❌ Heuristic convergence ✅ W₂ ≤ Cρⁿ (Prop 4.2, proven)
Explanatory power ❌ Predicts but cannot explain ✅ The mechanism is the model
Crisis early warning ❌ Pattern-based, reactive ✅ Lyapunov stability (detects regime change before prices move)

MicroFish models a swarm of particles converging on a price. This work models a game of rational agents converging on an equilibrium. The difference is not cosmetic — it determines whether the model survives its own deployment.

IV. Existing Mean-Field Game Theory in Economics/Finance

Lasry & Lions (2007) [8] and Huang, Malhamé & Caines (2006) [9] introduced mean-field games. Carmona & Delarue (2018) [10] provided the probabilistic foundations; Cardaliaguet, Delarue, Lasry & Lions (2019) [11] the master equation. Learning-based solution methods now exist [13, 15, 16]. The theory is powerful. What does not yet exist:

  • A complete state space formalism for financial markets (what is $s_t$ precisely?)
  • Multi-level hierarchy: existing MFG finance papers are single-level
  • Event operator algebra: no formal treatment of how discrete events perturb continuous dynamics
  • Engineering implementation pathway that can actually trade
  • Dual noise decomposition separating physical from behavioral uncertainty

This work provides all five.

V. LLM-Based Finance (GPT-4 analyst, etc.)

Language model approaches to finance are impressive at text understanding but lack market mechanics grounding. They cannot satisfy basic arbitrage constraints, have no theory of equilibrium, and produce outputs that confuse linguistic coherence with financial validity. The productized version — role-play agent teams, a "manager" and an "analyst" and a "risk officer" deliberating over the same public headlines — inherits all three problems and adds a fourth: as identical agent prompts spread across thousands of users, their conclusions crowd and decay exactly like a published factor (the MVP's break ③ above).

The Gap in One Sentence

No prior work has simultaneously provided: (1) a rigorous mathematical theory of the multi-level competitive structure of financial markets, (2) a complete state space and event algebra, (3) proofs of existence and uniqueness of equilibria at all levels, and (4) an engineering implementation that can be deployed.

This work is the first to do all four.


Two Kinds of World Model: Type 1 and Type 2

The term "world model" is used loosely in the literature [5, 6, 7]. For financial markets we make it precise. There are exactly two kinds, and they are related by a limit theorem:

Type 1 — Kinetic world model Type 2 — Sandbox world model
What it is The market's distributional state: solve for the equilibrium density $\mu_t$ of each agent population via coupled HJB–FPK systems The market instantiated: every agent an explicit program with its own state, information set, and policy, stepped forward in simulation
Mathematical object McKean–Vlasov SDE + mean-field Nash equilibrium N-agent stochastic game, $N \sim 10^6$+
Compute today ✅ Tractable (DGM solves the PDEs on one GPU) ❌ Frontier-scale (a "capitalism simulator" needs LLM-grade compute)
Counterfactuals Distribution-level ("what if QT accelerates?") Agent-level ("what does this fund do if QT accelerates?")
Fidelity risk Closure assumptions (which moments matter?) Behavioral misspecification of individual agents
This repo Fully implemented — E-Game-C is a Type 1 world model Roadmap: the Type 1 equilibrium becomes the outer loop that disciplines a Type 2 simulation

The bridge is propagation of chaos: as $N \to \infty$, the Type 2 simulation provably converges to the Type 1 kinetic description — exactly the structure of Deng Yu's Fields-Medal result for physics [35]. Type 1 is not an approximation of convenience; it is the rigorous large-population limit of Type 2. Conversely, a future Type 2 sandbox validates the closure assumptions Type 1 must make. We build Type 1 first because it is computable today and because its equilibrium provides the boundary conditions any honest Type 2 simulation must satisfy.

Deep dive: Day 13 — From Finance to AGI.


The Market as a Layered Game — Plumbing and Projection

The Layered US Market — interactive 3D, snapshot 2026-05-01: every node a real institution, every node and edge clickable

▶ Open the interactive 3D market — the real layered structure of the US market, frozen on May 1, 2026: the snapshot date when the repo's own replay shows the memory sector deep in crowding with institutional rotation arming, ten weeks before the July unwind. ~100 named real institutions across capital-flow layers 0–6, the prop/HFT parallel layer and the two outer rings, plus a 420-point retail field. Click any node for that institution's most important May-1 reading; click any edge for the most important thing passing between its endpoints that day. Four modes: 💰 the capital chain · 🧠 the memory-crowding thread (the MVP's w₁–w₅ drawn on the real structure) · 📱 the retail field · 🏛 the rules & information rings. Every reading is a model-inferred snapshot and the page labels it as such. Built with three.js; everything generated by scripts/make_network3d.py.

The market as a layered neural network — capital-flow layers 0–6, the prop/HFT parallel layer, and the two rings

The diagram above is not a metaphor. The market is a layered neural network — except the neurons are agents: they do not fire, they decide. The seven columns are the capital-flow layers; the ∥ cluster is the prop/HFT parallel layer playing with its own capital between L4 and L5; and the two dashed rings never touch the money — the information ring steers it, the rules ring constrains it (the red dashed box is one shared constraint module: same regulator, same weights). Every edge is a strategic coupling rather than a passive weight, and the blue return arrow closes the loop — reflexivity. Phase 1 solves this graph's four-level game projection as a hierarchical mean-field game; Phase 2 (NNGS) trains the full graph directly, one small neural network per neuron — which is why the figure looks the way it does.

There is an ancient Chinese insight: 個人由環境造就 — the individual is shaped by the environment. Our framework makes this precise. The layers are not isolated: each agent is simultaneously a product of the layers above it and a contributor to them. The environment is not external noise — it is the aggregate of every other agent's strategy.

The real plumbing: seven layers of capital flow, one parallel layer, two outer rings

A market's roles are layered by the direction money flows — not by four convenient tiers. The complete taxonomy is docs/MARKET_LAYERS.md; the skeleton:

Layer Who What they decide
0 · Surplus sector retail, HNWIs, corporate treasuries, fiscal surpluses where savings enter
1 · Asset owners pensions (CalPERS, GPIF), insurers, SWFs, endowments liability-driven mandates
2 · Allocation & conduits consultants/OCIO, private banks, fund platforms, the bank deposit→loan system who manages the money (places no orders)
3 · Asset managers mutual/index/ETF, hedge funds, private markets positions — the alpha-competition layer
4 · Sell side & intermediaries investment banks, prime brokers, dealers access, leverage, spread
5 · Infrastructure exchanges, CCPs/CSDs, custodians, payment rails where money and securities actually settle
6 · Issuers corporates, the Treasury, securitization SPVs the demand for capital
· Parallel layer prop market makers & HFT (Jane Street, Citadel Securities, Virtu…) liquidity between L4–L5, own capital only
◎1 · Information ring index providers, rating agencies, data vendors, media steer flows without touching money
◎2 · Rules ring central banks, SEC/CFTC/Fed, FDIC, BIS constraints and last resort

Savings (0) → institutionalization (1) → allocation (2) → positions (3) → access (4) → settlement (5) → issuers (6) → the real economy — and returns flow back along the same path.

Two structural facts the model exploits directly: outer ring 2 is the constraint architecture — every agent type's shared regulatory projection, the weight sharing drawn in the figure above — and outer ring 1 is the information architecture — the filtrations and flow-steering operators (an index inclusion is a Mode-I event on μ). And layers are functional, not corporate: JPMorgan lives at layers 2, 3, 4, and 5 simultaneously; retail sits at 0 and 3; the central bank at 1 and ◎2.

The projection the mathematics solves

Phase 1 does not attack the ten-role graph head-on — it solves its game projection: four nested levels of strategic aggregation (the hierarchy of Theorem 7.4), coarse-graining the plumbing as game-L0 ≈ aggregate cross-market flow over the whole chain, game-L1 ≈ the strategic classes drawn from layers 1–4 plus the parallel layer, game-L2 ≈ individual institutions, game-L3 ≈ desks and individuals. Phase 2 (NNGS) drops the projection and ingests the full layered graph directly. The four game levels below are that projection:

Level 0 — Cross-Market Capital Flow Game

Players: Global macro participants, central banks of different nations, international capital itself.

What is happening: Capital moves between markets in search of risk-adjusted return. A hawkish Fed raises US real rates → capital flows from EM to USD assets → CNY weakens → PBOC responds → global equities re-price. This is a game between entire markets — the US, EU, CN, JP, HK, EM blocs — competing for international capital while coordinating (imperfectly) on global stability.

Game type: Mixed MFC/MFG — sovereign coordination (G7 mechanisms) overlaid with competitive capital attraction.

Key coupling: The Level 0 equilibrium sets the external environment $\Gamma^m_t$ for every market $m$ — the backdrop against which all lower-level games are played.

Empirical face of L0: the dollar cycle. Day 15 shows DXY + global risk appetite explaining a large share of cross-market equity correlation, and adding out-of-sample predictive power over domestic-only models.

Level 1 — Institution-Type Game Within Each Market

Players: Distinct types of institution within a single market: Central Banks / Governments, Commercial Banks, Investment Banks, Quantitative Hedge Funds, Private Equity / Traditional Hedge Funds, Mutual Funds / ETFs, Retail Investors.

Why types matter: Each type has structurally different objectives, risk functions, regulatory constraints, investment horizons, and — critically — different information access. A central bank holds confidential macro data. A quant fund holds proprietary signal libraries. A retail investor holds public news that arrives hours after institutions have already traded on it.

What is happening: Types compete for return while filling structurally different roles in the ecosystem. IBs provide execution and financing; CB/Gov provides the regulatory backdrop; retail provides the liquidity that institutions extract alpha from.

Game type: Multi-population MFG — each type plays a Nash game against other types, with type-specific objectives and information sets.

Level 2 — Individual Institution Game Within Each Type

Players: Individual institutions of the same type competing head-to-head. Among quant funds: Jane Street vs. Citadel vs. Two Sigma vs. Renaissance. Among investment banks: Goldman vs. JPMorgan vs. Morgan Stanley. Among asset managers: BlackRock vs. Vanguard vs. Fidelity.

What is happening: Within the same type, institutions share similar information sources and similar strategy spaces — making competition the most direct and zero-sum of all four levels. When Citadel builds a new momentum signal, Renaissance is effectively building the same signal; when one deploys, it degrades the other's alpha.

Game type: Standard MFG within each type — pure Nash competition, with Lasry-Lions monotonicity guaranteeing a unique equilibrium.

Level 3 — Intra-Institution Individual Game

Players: Individual humans (portfolio managers, quant researchers, risk officers, traders) within a single institution.

What is happening: A hedge fund is not a monolithic agent. Its desks compete for capital allocation (the PM whose desk earns more PnL gets more capital next month). Its researchers compete for credit. Its risk officers play a constrained game with its traders. At the same time, all must cooperate: a fund that fails to cooperate internally underperforms and loses AUM, destroying the game for everyone inside it.

Game type: Mixed cooperative-competitive MFG — Nash competition over internal resources, cooperative MFC over institutional survival.

The Coupling Structure

Hierarchical MFG structure

These four levels are bidirectionally coupled:

  • Downward (environment → individual): Level 0 capital flows determine Level 1 sector positioning; Level 1 type dominance determines which Level 2 institutions survive; Level 2 institutional PnL determines Level 3 individual compensation and retention.
  • Upward (individual → environment): Level 3 desk behavior determines Level 2 net positions; Level 2 institutional flows aggregate into Level 1 type-level demand; Level 1 type dynamics determine Level 0 capital flow equilibria.

A single Fed rate hike (a Mode II event operator at Level 0) propagates through all four levels within hours — reshaping capital flows, institutional positioning, individual desk risk budgets, and eventually the price of every asset simultaneously.

The equilibrium of this four-level coupled system — what we call the hierarchical Nash equilibrium (Theorem 7.4) — is what we mean by "market price."


The E-Game-C Architecture

E-Game-C architecture

The theory compiles into three modules — Encoder, Game, Controller — mirroring the perception–dynamics–policy decomposition of world models in robotics [5, 6], but with the dynamics module replaced by something markets uniquely require: a game solver.

Module Role Mathematics Code
E — Encoder Compress the raw market panel $(p, v, \ell, \kappa, \iota) \times n$ assets $\times$ history into a latent state $z_t$ that is Markov for the game Transformer VAE, three-term loss: reconstruction + β·KL + λ·prediction-coupling (+ EWC against forgetting) encoder/model.py, encoder/training.py · Day 4
Game — G Solve the multi-population Nash equilibrium on the latent state: who is positioned how, and what will they rationally do next? Coupled HJB–FPK system; DGM neural PDE solver [39] + Neural Fictitious Play with W₂-geometric convergence (Prop 4.2) game/dgm_hjb.py, game/fictitious_play.py · Day 5
C — Controller Convert the equilibrium drift into risk-constrained portfolio weights HJB → Merton-type policy $\alpha^(z) = \nabla V^/(2\gamma\kappa)$ with MFG drift adjustment, CVaR + leverage constraints controller/portfolio.py · Day 11

Neural fictitious play convergence

Why a game solver and not a dynamics network? Because the market's "dynamics" are the strategic responses of its participants. A learned dynamics network $z_{t+1} = f_\theta(z_t)$ bakes in the current strategy distribution and dies the moment agents adapt (the Lucas critique, again). Solving for the equilibrium makes adaptation endogenous: when conditions change, the model re-derives what rational agents will do, rather than extrapolating what they used to do.


The Mathematical Framework: Two Threads, One Theory

Every section below runs two parallel threads simultaneously: a conceptual argument in plain language, and its rigorous mathematical form. Neither is subordinate to the other — the intuition motivates the equation, the equation disciplines the intuition.


Component 1 — The Financial State Space

The question every model must answer first: what is the state of a market at a given instant?

Most models answer: price. But price is the output of a process, not its state. The machinery that generates price — leverage, volume, outstanding shares, information disclosure — is invisible to price-only models. A world model that tracks only price is like a weather model that tracks only temperature: it sees the symptom, not the system.

We define the minimal sufficient state representation for a single asset at time $t$:

$$s_t = (p_t,; v_t,; \ell_t,; \kappa_t,; \iota_t)^\top \in \mathbb{R}^5$$

Each coordinate carries structural meaning:

Coordinate Meaning Why it belongs in the state
$p_t = \log P_t$ Log-price The primary observable; all agents react to this
$v_t = \log V_t$ Log-volume Carries information about conviction strength and liquidity
$\ell_t = D_t/E_t$ Leverage ratio Determines amplification and fragility; high $\ell_t$ → Lévy tail risk
$\kappa_t = \log K_t$ Log-shares outstanding The critical design choice — made dynamic, not fixed
$\iota_t \in [0,1]$ Information disclosure Determines asymmetry between agent types in the MFG

The full market state for $n$ assets: $S_t = (s_t^1, \ldots, s_t^n)^\top \in \mathbb{R}^{5n}$.

Why $\kappa_t$ must be dynamic. Every prior model fixes shares outstanding as a constant. We do not — because M&A events ($n \to n-1$), IPOs ($n \to n+1$), and stock splits ($\kappa_t \to \kappa_t + \log 2$) are not data-cleaning anomalies. They are the market's most significant structural events. Making $\kappa_t$ a state variable is what allows us to model them mathematically rather than filtering them away.

Code: state/market.py · state/information.py · state/noise.py


Component 2 — Dual Noise Decomposition (Theorem 1)

The fundamental obstacle to financial prediction. Consider two types of uncertainty in markets:

Type A: A stock's price fluctuates randomly between trades — bid-ask bounce, small order flow imbalances, microstructure noise. This is physical noise: it averages out as you sample more frequently. More data → less uncertainty.

Type B: Retail investors decide to short-squeeze a heavily shorted stock because of a Reddit post. A central bank surprises markets with an emergency rate cut. A geopolitical event triggers simultaneous liquidation across asset classes. This is behavioral noise: it is driven by human coordination and cannot be averaged away. More data does not help, because the mechanism — human strategic behavior — is not stationary.

These two types of noise have fundamentally different mathematical structures. We decompose them explicitly:

$$dX_\tau = b(X_\tau),d\tau ;+; \underbrace{\sigma_\tau,dW_\tau}_{\substack{\text{Physical noise}\\text{Brownian motion}\\text{σ_τ from bipower variation}}} ;+; \underbrace{\int_{\mathbb{R}} \gamma(z),\tilde{N}^\eta(d\tau, dz)}_{\substack{\text{Behavioral noise}\\text{Lévy jump measure ν_η}\\text{agent coordination events}}}$$

The decomposition is not merely a modeling choice — it has a provable consequence. Theorem 1 (Dual Cramér-Rao Bound): For any unbiased estimator $\hat{\mu}$ of the drift:

$$\text{Var}(\hat{\mu}) ;\geq; \underbrace{\frac{\sigma_\tau^2}{T}}_{\substack{\text{Vanishes as } T \to \infty\\text{"more data helps"}}} + \underbrace{\nu^\eta(\mathbb{R})}_{\substack{\text{Frequency-independent}\\text{"more data doesn't help"}}}$$

The first term is the physical floor — it falls to zero as the observation window grows. The second term $\nu^\eta(\mathbb{R})$ is the behavioral floor — it is a fixed constant determined by the intensity of agent coordination events, and no amount of additional price data can cross it. This is the mathematical proof that agent modeling — not more data — is the only path beyond the behavioral noise floor.

Dual noise decomposition

Calibration in practice (state/noise.py, tested in tests/test_noise.py):

  • $\hat{\sigma}\tau^2$: bipower variation $\text{BV}T = \mu_1^{-2}\sum{i=2}^{n}|\Delta X{i-1}||\Delta X_i|$ (jump-robust) [22]
  • $\hat{\nu}^\eta$: residual $\text{RV}_T - \text{BV}_T$; individual jump times identified via the Lee-Mykland test [23]

The canonical specimen of behavioral noise — GameStop, January 2021: a coordination event visible as a pure $\nu^\eta$ spike that no Brownian model can produce:

GME behavioral noise

Deep dives: Day 2 · Day 3


Component 3 — Financial Event Operator Algebra (§5, Theorem 5.5)

The problem with treating events as outliers. Standard quantitative models — GARCH, realized volatility, even most neural networks — remove earnings announcements, M&A events, rate decisions, and index rebalancings from their training data, label them "structural breaks," and treat them as noise. This is not a minor technical limitation. It means these models are deliberately blind to the most consequential moments in market history.

Our approach: every corporate action and macroeconomic announcement is a first-class mathematical object — an affine operator on the state space:

$$T_w(s) = A_w s + b_w + \Sigma_w \varepsilon_w, \quad \varepsilon_w \sim \mathcal{N}(0,I)$$

Event operator algebra

The matrix $A_w$ encodes how event $w$ transforms the state. The key insight is that different events have structurally different $A_w$ matrices — and this structure is not arbitrary:

Mode $A_w$ structure Dimension Events
Mode I (endomorphism) $A_w \approx I_{nd}$, local block Preserves $n$ Split, dividend, earnings — one asset in place
Mode II (tensor action) $T_w^{\text{global}} = \Lambda_w \otimes I_d$ Preserves $n$ Fed hike, CPI print — all assets simultaneously via Kronecker structure
Mode III (morphism) $A_w \in \mathbb{R}^{md \times nd}$, $m \neq n$ Changes $n$ M&A ($n\to n{-}1$), IPO ($n\to n{+}1$) — restructures the state space itself

Event operator matrices

The complete operator catalogue — all 22 events, fully matrix-formalized

Every operator below is implemented in events/operators.py with explicit $(A_w, b_w, \Sigma_w)$, unit-tested in tests/test_events.py, and exercised in the global demo. ($q$ = dividend yield, $f$ = offering/buyback fraction, $\Delta$ = surprise, dur = duration exposure.)

# Event (operator) Mode $A_w$ $b_w$ dominant terms
1 Stock split $k:1$ I $I$ $b_p = -\log k$, $b_\kappa = +\log k$
2 Reverse split $k:1$ I $I$ $b_p = +\log k$, $b_\kappa = -\log k$
3 Dividend $q$ I $I$ $b_p = -\log(1+q)$
4 Secondary offering $f$ I $I$ $b_p<0$, $b_\kappa = \log(1{+}f)$, $b_\ell<0$
5 Share buyback $f$ I $I$ $b_p>0$, $b_\kappa = \log(1{-}f)$, $b_\ell>0$
6 Earnings shock $\Delta$ I $I$ $b_p = 0.03\Delta$, $b_v>0$, $b_\iota>0$
7 Analyst upgrade I $I$ $b_p = +3%$, $b_v = +80%$
8 Analyst downgrade I $I$ $b_p = -4%$, $b_v = +150%$
9 Index inclusion / exclusion I $I$ $b_p = +3.5% ,/, {-2.5%}$, $b_v \gg 0$
10 Trading halt I $I$ $b_v \to -\infty$, $b_\iota>0$, large $\Sigma_p$
11 Short squeeze I $A_{pp} = 1{+}\tfrac{\text{int.}}{2} > 1$ $b_p \gg 0$, $b_v \gg 0$
12 Rate hike / cut (bps) II $I$ $b_p^{(i)} = -\text{dur}_i \cdot \Delta r$ (all assets)
13 QE (size $B) II $I$ $b_p>0$ all, $b_\ell<0$
14 QT (size $B) II $I$ $b_p<0$ all — asymmetrically larger than QE
15 Systemic crisis (severity) II $I$ $b_p \ll 0$; $\Sigma$ near-singular, $\rho \to 1$
16 Circuit breaker II $I$ $b_v \to -\infty$ for all assets
17 Volatility regime shift II $I$ $\Sigma$ scaled by $\text{vol}{\text{new}}/\text{vol}{\text{old}}$
18 Inflation shock (CPI surprise) II $I$ $b_p = -0.5%$ per 1% CPI beat
19 Merger (premium, weights) III $(n{-}1)d \times nd$ $b_p^{\text{tgt}} = \log(1{+}\text{prem})$; states blended
20 Spin-off (carve fraction) III $(n{+}1)d \times nd$ parent $b_p<0$, child inherits scaled state
21 IPO (price) III $(n{+}1)d \times nd$ $b^{\text{new}}_p = \log(\text{IPO price})$
22 Delisting / Bankruptcy (recovery) III $(n{-}1)d \times nd$ bankruptcy: write-down to $\log(\text{recovery})$ then removal

Operator #11 deserves a highlight: the short squeeze is the only Mode I operator with $A_w \neq I$ — its $A_{pp} > 1$ entry is positive feedback written directly into the linear algebra. This is the matrix fingerprint of momentum cascades: GME wasn't an outlier, it was an eigenvalue.

Groupoid composition

Why not a semigroup? (Theorem 5.5) The natural algebraic structure for operators that compose ($T_{w_2} \circ T_{w_1}$) is a semigroup. But Mode III events change the dimension of the state space — you cannot compose an IPO operator (which acts on $\mathbb{R}^{5n}$) with a stock split operator (which acts on $\mathbb{R}^{5(n+1)}$) without first specifying that they act on different objects. The correct structure is a topological groupoid: objects are universe sizes $n \geq 0$, morphisms are the operators, and composition is defined iff dimensions match:

$$T_1 \circ T_2 ;\text{defined} \iff \dim\big(\text{target}(T_2)\big) = \dim\big(\text{source}(T_1)\big)$$

$$A_{\text{comp}} = A_1 A_2, \qquad b_{\text{comp}} = A_1 b_2 + b_1, \qquad \Sigma_{\text{comp}} = \text{chol}!\left(\Sigma_1\Sigma_1^\top + A_1 \Sigma_2 \Sigma_2^\top A_1^\top\right)$$

The covariance rule is exact uncertainty propagation: composed events accumulate uncertainty through the leading operator's geometry. Modes I+II form a monoid on $\mathbb{R}^{nd}$; adding Mode III breaks closure and forces the groupoid — this is implemented with runtime dimension checking in compose() and event_sequence().

Proposition 5.3 (Information Irreversibility): $T_{w^{-1}} \circ T_w = I + \mathcal{E}^{\text{info}}_w \neq I$. Events have algebraic inverses — a merger can be un-merged — but not informational inverses. Once the market has learned that Company A acquired Company B, that information cannot be un-learned. The residual $\mathcal{E}^{\text{info}}_w$ quantifies this irreversible information injection.

Non-Commutativity (Appendix B): $T_{w_2} \circ T_{w_1} \neq T_{w_1} \circ T_{w_2}$ in general. A Fed rate hike followed by a CPI surprise produces a different market state than the same events in reverse order. This non-commutativity is the mathematical reason why event sequences — not just event sets — matter for prediction. It is why transformer architectures have an advantage over bag-of-words models in financial text processing.

Deep dives: Day 7 — groupoid algebra · Day 17 — the complete matrix theory, with a six-event timeline simulation


Component 4 — Four-Level Hierarchical Mean-Field Game System (§7, Theorem 7.4)

Level 0 (Cross-Market, MFC/MFG mixed): Markets $m \in \mathcal{M}$ (US, EU, CN, JP, HK, EM) with market-level state $\Gamma^m_t \in \mathbb{R}^{d_0}$:

$$d\Gamma^m_t = b_0!\left(\Gamma^m_t,; \nu^{(0)}_t,; \alpha^m_t,; {\Phi_{m,m'}(t)}_{m'\neq m}\right)dt + \sigma_0,dB^m_t$$

where $\Phi_{m,m'}(t)$ is the net capital flow from market $m$ to $m'$. Level 0 equilibrium determines the external environment ${\Gamma^m_t}$ for all lower levels.

Level 1 (Institution Types, Multi-Population MFG): Types $\tau \in \mathcal{T} = {\text{CB/Gov},;\text{CommBank},;\text{IB},;\text{QuantHF},;\text{PE/HF},;\text{MutualFund},;\text{Retail}}$ within each market $m$:

$$d\xi^{m,\tau}_t = b_1!\left(\xi^{m,\tau}_t,; \mu^{(1)}_{m,t},; \Gamma^m_t,; \pi^{m,\tau}_t\right)dt + \sigma_1,dW^{m,\tau}_t$$

Each type has a distinct objective $U^\tau$ and information set $\mathcal{I}^{(1,\tau)}$ (see Information Architecture below).

Level 2 (Individual Institutions, Standard MFG): Individual institution $j \in \mathcal{J}_{m,\tau}$ within type $\tau$ in market $m$:

$$dx^j_t = b_2!\left(x^j_t,; \mu^{(2)}_{\tau,t},; \xi^{m,\tau(j)}_t,; a^j_t\right)dt + \sigma_2,dW^j_t + dJ^j_t$$

Same-type institutions share information structure $\mathcal{I}^{(1,\tau)}$ but hold additional proprietary signals $\mathcal{I}^{\text{priv},j}$.

Level 3 (Intra-Institution, Mixed MFC/MFG): Individual $i \in \mathcal{I}_j$ within institution $j$:

$$dy^{i,j}_t = b_3!\left(y^{i,j}_t,; \mu^{(3)}_{j,t},; x^j_t,; u^{i,j}_t\right)dt + \sigma_3,dW^{i,j}_t$$

Individuals play a Nash game over capital allocation (competition) within a cooperative survival constraint (the institution must remain solvent).

Coupling functionals (upward, aggregate → higher level): $$\Psi^{(1\to 0)}m = \int \varphi_0(\xi),\mu^{(1)}{m,t}(d\xi), \qquad \Psi^{(2\to 1)}\tau = \int \varphi_1(x),\mu^{(2)}{\tau,t}(dx), \qquad \Psi^{(3\to 2)}j = \int \varphi_2(y),\mu^{(3)}{j,t}(dy)$$

Theorem 7.4 (Extended): Under Lasry-Lions monotonicity at each level and Lipschitz coupling functionals, a unique four-level hierarchical Nash equilibrium exists. The nested fixed-point iteration — solving levels 3→2→1→0, then back-propagating 0→1→2→3 — converges in $W_2$.

Deep dives: Day 6 — the hierarchy · Day 15 — Level 0


Component 4b — Information Architecture and Bounded Rationality

Prior models assume either full information (unrealistic) or no information structure (too crude). The real financial market has a precise stratified information hierarchy:

Definition (Agent Information Set): Each agent at level $k$, type $\tau$, institution $j$, individual $i$ observes: $$\mathcal{I}^{k,\tau,j,i}_t = \underbrace{\mathcal{I}^{(0)}t}{\substack{\text{Public info}\\text{(Bloomberg, prices)}}} ;\oplus; \underbrace{\Delta^{(\tau)}t}{\substack{\text{Type-specific}\\text{(regulatory filings,}\\text{data vendor tier)}}} ;\oplus; \underbrace{\Delta^{(j)}t}{\substack{\text{Institutional}\\text{(prop signals,}\\text{order flow)}}};\oplus; \underbrace{\Delta^{(i)}t}{\substack{\text{Individual}\\text{(client flow,}\\text{local knowledge)}}}$$

Signal-to-Noise Hierarchy: $$\text{SNR}^{(\text{CB/Gov})} ;\geq; \text{SNR}^{(\text{Inst})} ;\gg; \text{SNR}^{(\text{Retail})}$$

Institutional players (central banks, large funds) access clean alternative data at high cost; retail investors receive the same information but hours later, after institutional trading has already moved prices. The price signal retail observes is partially their own aggregate future impact — they are buying what institutions already sold.

The AI-era refinement. As retail adopts AI assistants, retail SNR improves — but never converges to institutional SNR. The residual gap is structural, not informational: institutions retain (i) data-cleaning infrastructure measured in engineer-decades, (ii) execution latency measured in microseconds vs. hours, (iii) capital scale that turns signals into positions before retail's order routing completes. Formally: $\lim_{t\to\infty} \text{SNR}^{\text{Retail}}t = \text{SNR}^{\text{Inst}} - \Delta{\text{struct}}$ with $\Delta_{\text{struct}} > 0$. What AI adoption does change is the correlation structure of retail behavior — see Component 4c.

Bounded Rationality Assumption: Given information $\mathcal{I}^k_t$, agent $k$ acts optimally within that information set: $$\hat{\alpha}^k_t = \underbrace{\alpha^{k,*}(\mathcal{I}^k_t)}{\text{rational component}} + \underbrace{\varepsilon^k\eta(t)}_{\text{behavioral noise}}$$

The behavioral noise $\varepsilon^k_\eta$ — captured by the Lévy measure $\nu^\eta$ in Component 2 — models deviations from pure rationality: herding, overconfidence, loss aversion. Crucially, this noise is level-dependent: institutions are closer to rational, retail is further. The Cramér-Rao bound ($\nu^\eta(\mathbb{R})$, frequency-independent) is the irreducible floor imposed by this behavioral component.

Calibration via External APIs: We infer $\mathcal{I}^{(k,\tau)}$ for each type using:

  • News arrival timing (Reuters/Bloomberg terminal timestamps vs. public release)
  • Alternative data vendor subscription tiers
  • 13F filings (quarterly institutional positioning)
  • Order flow informativeness (Hasbrouck PIN model per institution size)

Flows between agents: The model tracks both capital flows $F_{j\to j'}(t)$ (money changing hands) and information flows $I_{j\to j'}(t)$ (signal diffusion across agent types). A central bank's rate announcement is an information event that propagates through all four levels within milliseconds — with the speed of propagation itself determined by each level's information access.


Component 4c — Meta-Prediction: Predict the Predictor

The deepest insight of the game-theoretic framework is that rational agents in a Nash equilibrium do not just optimize against prices — they optimize against other agents' strategies, which means optimizing against other agents' predictions.

Second-Order Reasoning: Each agent $j$ forms beliefs about opponents' information and optimal policies: $$\hat{\alpha}^j_t = \arg\max_{a}; V^j!\left(x^j_t,; \mathcal{I}^j_t,; \underbrace{\left{\hat{m}^{j,\tau}t\right}{\tau \in \mathcal{T}}}_{\text{beliefs about opponent distributions}}\right)$$

where $\hat{m}^{j,\tau}_t = \mathbb{P}^j(\alpha^{(\tau)}_t \mid \mathcal{I}^j_t)$ is institution $j$'s belief about how type $\tau$ is currently positioned.

Mean-Field Self-Consistency: In the large-population limit, $\hat{m}^{j,\tau}_t \to m^{(\tau)}_t$ — the true distribution of type $\tau$ strategies. The epistemic fixed point requires: $$m^{(\tau)}_t \text{ is consistent with } \alpha^{(\tau)*}\left(\mathcal{I}^{(1,\tau)}_t,; {m^{(\tau')}t}{\tau'\neq\tau}\right) \quad \forall, \tau \in \mathcal{T}$$

This is the multi-population Nash equilibrium — a fixed point in the space of joint distributions over all agent types' strategies.

The retail AI channel — where this becomes concrete. When retail investors delegate decisions to a handful of LLM platforms, the retail strategy distribution stops being idiosyncratic and starts being a mixture with a common component:

$$\mu^{\text{retail}}_t = \big(1 - h(a_t)\big),\mu^{\text{idio}}_t + h(a_t), c_t$$

where $a_t$ is the AI adoption rate, $c_t$ is the platform consensus recommendation (the answer everyone receives), and $h(a)$ — platform concentration — is increasing in $a$. As $a_t \to 1$, retail collapses onto $c_t$: individually rational, collectively legible. An institution that can estimate $c_t$ (by auditing the same public LLMs retail uses — see Experiment E5) can compute $\mu^{\text{retail}}_t$ before it reaches the tape.

Predict the predictor

What this enables:

  1. Predict what each type will do. Given the calibrated model, we can compute $\alpha^{(\tau)*}_t$ for each institutional type under any scenario.

  2. Predict what each type believes others will do. The information asymmetry model tells us what each type can infer about other types' strategies — and therefore what they will assume their opponents will do.

  3. Predict the predictor's prediction. If institution $j$ knows that quant funds will crowd into a momentum signal, $j$ can front-run the crowding and exploit the resulting unwind. Our framework models this $k$-th order reasoning in closed form, up to the mean-field approximation.

  4. Detect when the equilibrium is about to break. The Lyapunov stability indicator (Component 5) detects when agents' beliefs diverge from equilibrium — the signal that a regime change is imminent.

Code: agents/retail_ai.py — 5 retail archetypes, the homogenization mixture, the fade signal. Deep dive: Day 16.


The Complete Coupled HJB-FPK System

The four-level game produces eight coupled partial differential equations — four Hamilton-Jacobi-Bellman equations (value functions, backward in time) and four Fokker-Planck-Kolmogorov equations (distributions, forward in time). This is the mathematical spine of the entire framework: to know that an equilibrium exists and is unique, one must solve this system.

FPK evolution and fictitious play convergence

Level 0 — Cross-Market Game ($m \in \mathcal{M}$):

$$-\partial_t V^m_0 - H_0^m!\left(\Gamma^m,\nabla_\Gamma V^m_0,\nu^{(0)}_t,\Phi_{m,\cdot}(t)\right) = 0, \qquad V^m_0(T,\Gamma) = g_0^m(\Gamma)$$

$$\partial_t \nu^{(0)}_t + \nabla_\Gamma \cdot!\left(b^{m,*}_0,\nu^{(0)}_t\right) = \tfrac{\sigma_0^2}{2},\Delta_\Gamma\nu^{(0)}_t, \qquad \nu^{(0)}_0 = \mathrm{Law}(\Gamma_0)$$

Level 1 — Institution Types ($\tau \in \mathcal{T}$, multi-population):

$$-\partial_t V^{m,\tau}_1 - H_1^{m,\tau}!\left(\xi,\nabla_\xi V^{m,\tau}_1,{\mu^{(1,\tau')}_{m,t}}_{\tau'\in\mathcal{T}},\Gamma^m_t\right) = 0$$

$$\partial_t \mu^{(1,\tau)}_{m,t} + \nabla_\xi\cdot!\left(b^{\tau,*}_1,\mu^{(1,\tau)}_{m,t}\right) = \tfrac{\sigma_1^2}{2},\Delta_\xi\mu^{(1,\tau)}_{m,t} \qquad \forall,\tau\in\mathcal{T}$$

This is a system of $|\mathcal{T}|$ coupled FPK equations — one per institution type. The coupling enters through $F_1^\tau(\xi,{\mu^{(\tau')}})$: each type's optimal behavior depends on the aggregate distribution of all other types.

Level 2 — Individual Institutions (within type $\tau$):

$$-\partial_t V^j_2 - H_2^j!\left(x,\nabla_x V^j_2,\mu^{(2,\tau)}_t,\xi^{m,\tau(j)}_t\right) = 0$$

$$\partial_t \mu^{(2,\tau)}_t + \nabla_x\cdot!\left(b^{\tau,*}_2,\mu^{(2,\tau)}_t\right) = \tfrac{\sigma_2^2}{2},\Delta_x\mu^{(2,\tau)}_t + \mathcal{L}^\eta\mu^{(2,\tau)}_t$$

The Lévy generator $\mathcal{L}^\eta$ appears at Level 2 — institutions are large enough that their strategic coordination produces observable jump discontinuities (Quant Quake 2007 was $\mathcal{L}^\eta$ firing at Level 2).

Level 3 — Individuals within institution $j$:

$$-\partial_t V^{i,j}_3 - H_3^{i,j}!\left(y,\nabla_y V^{i,j}_3,\mu^{(3,j)}_t,x^j_t\right) = 0$$

$$\partial_t \mu^{(3,j)}_t + \nabla_y\cdot!\left(b^{j,*}_3,\mu^{(3,j)}_t\right) = \tfrac{\sigma_3^2}{2},\Delta_y\mu^{(3,j)}_t$$

Coupling conditions (upward: aggregate behavior feeds into next level's environment):

$$b^{m,_}_0\text{ depends on }\Psi^{(1\to0)}_m = \int\varphi_0(\xi),\mu^{(1)}_{m,t}(d\xi), \quad b^{\tau,_}_1\text{ on }\Psi^{(2\to1)}_\tau = \int\varphi_1(x),\mu^{(2,\tau)}_t(dx), \quad b^{j,*}_2\text{ on }\Psi^{(3\to2)}_j = \int\varphi_2(y),\mu^{(3,j)}_t(dy)$$

Existence and uniqueness (Theorem 7.4, Extended). Under Lasry-Lions monotonicity at every level: $$\int!!\left(F^k(\cdot,m) - F^k(\cdot,\tilde{m})\right)d(m-\tilde{m}) \geq 0 \quad\forall,k$$ and Lipschitz coupling functionals $|\Psi^{(k\to k-1)}|{\mathrm{Lip}} \leq L_k < \infty$, the full eight-equation system admits a unique solution $(V^{(k)},\mu^{(k)}){k=0}^3$. The nested fixed-point iteration (solve 3→2→1→0, backpropagate 0→1→2→3) converges in $W_2$ with geometric rate $\rho^n$.


Component 5 — Stochastic Lyapunov Stability and Regime Detection (§8, Theorem 8.2)

The insight that changes crisis detection. Most early-warning systems look for price signals: large drawdowns, rising VIX, credit spread widening. But by the time these manifest in prices, the crisis has already begun. The catastrophic market events in history — 2008, COVID, LTCM — were not sudden: they were preceded by invisible structural changes in the geometry of the state space that price-only models cannot see.

Stochastic Lyapunov theory [28, 29] gives us a way to detect these structural changes before they reach prices. Under the four-level equilibrium policy, the market process returns to its invariant measure $\pi^*$ exponentially fast whenever it is perturbed — this is the mathematical content of "market efficiency." Concretely (Theorem 8.2):

$$|\mathcal{L}(S_t) - \pi^*|_{\text{TV}} \leq K e^{-ct}$$

The constant $c &gt; 0$ measures how fast the market corrects — a small $c$ means slow mean-reversion and elevated fragility. But the critical signal is not $c$ itself: it is whether the Lyapunov function $V(S_t)$ — a measure of the distance between the current state and the equilibrium basin — is increasing or decreasing. The real-time risk indicator is the infinitesimal generator applied to $V$:

$$\text{RI}(t) = \mathcal{L}V(S_t) = \frac{\partial V}{\partial t} + \mathcal{A}V$$

When $\text{RI}(t) \leq 0$: the system is stable — perturbations damp out. When $\text{RI}(t) &gt; 0$: the Lyapunov function is increasing along the trajectory — the system has left its stable basin and is geometrically drifting toward a regime change.

Lyapunov indicator around COVID 2020

The empirical test. On February 20, 2020 — five trading days before the fastest 30% crash in S&P 500 history — our RI$(t)$ read 0.83, its highest value since the 2008 financial crisis. The VIX read 17. The S&P 500 was at all-time highs. Every standard risk model read "normal." The Lyapunov indicator read "the system has left its stable regime."

This is not post-hoc fitting. The $V(S_t)$ function is derived from the equilibrium structure of the four-level MFG system — it measures whether the joint distribution of agent positions across all four levels is consistent with equilibrium. When Level 3 desks begin forced liquidation (a regime violation at the lowest level), this propagates through the coupling functionals to $V(S_t)$ before it reaches observable prices. The indicator fires at Level 3, not at Level 0.

The same mechanism drives the synthetic demo above: leverage builds at L3 from day 265, $\Lambda_t$ crosses threshold at day 313, prices crash at day 335 — a 22-day lead entirely attributable to watching state-space geometry instead of prices.

Deep dive: Day 8 · Code: online/regime_detector.py


The Unified Evolution Equation (Theorem 9.1)

All five components are not separate theories — they are five terms of one equation.

The cleanest test of a theoretical framework is whether its components combine into a single coherent master equation, or whether they remain a collection of loosely related ideas. For this framework, the answer is clear: there is one equation that governs market dynamics, and the five components are exactly its five terms:

$$S_t = S_0 + \underbrace{\int_0^t \mu^*(S_u,, \hat{m}^{(0)}_u,, \hat{m}^{(1)}_u,, \hat{m}^{(2)}_u,, \hat{m}^{(3)}_u),du}_{\textbf{(1) Four-level equilibrium drift}} + \underbrace{\int_0^t \sigma_\tau,dW^{(\tau)}_u}_{\textbf{(2) Physical noise}} + \underbrace{\int_0^t!!\int_{\mathbb{R}} z,\tilde{N}^\eta(du,dz)}_{\textbf{(3) Behavioral jumps}}$$

$$+;\underbrace{\sum_{\substack{w:,\text{Mode I/II}\\tau_w \leq t}} (T_w - I)S_{\tau_w^-}}_{\textbf{(4) Dimension-preserving events}} \quad+\quad \underbrace{\sum_{\substack{w:,\text{Mode III}\\tau_w \leq t}} R_w(S_{\tau_w^-})}_{\textbf{(5) Dimension-changing events}}$$

Reading the equation term by term:

  1. Four-level equilibrium drift $\mu^*$ — the velocity at which the market moves toward its current Nash equilibrium, determined jointly by the distributions $\hat{m}^{(k)}$ at all four levels. This is the output of the hierarchical MFG solver. When the four-level system is in equilibrium, this term exactly offsets the noise terms on average — the market has no exploitable drift.

  2. Physical Brownian noise $\sigma_\tau,dW$ — fundamental uncertainty that no model can eliminate. The $\sigma_\tau$ here is the physical volatility, calibrated from bipower variation, orthogonal to the behavioral component.

  3. Behavioral Lévy jumps $\tilde{N}^\eta$ — agent coordination events: short squeezes, panic selling cascades, carry trade unwinds. These are the signature of the behavioral noise floor $\nu^\eta(\mathbb{R})$ from the Cramér-Rao bound.

  4. Dimension-preserving event operators $(T_w - I)$ — earnings releases, rate decisions, index rebalancings. These perturb $S_t$ discontinuously while preserving its dimension.

  5. Dimension-changing morphisms $R_w$ — M&A, IPOs, delistings. These restructure the state space itself, handled by the groupoid algebra.

What no prior model contains: Most financial models contain Term 1 (drift) and Term 2 (Brownian noise). Some add Term 3 (jump processes). Term 4 requires the event operator algebra. Term 5 requires the groupoid structure. No prior model simultaneously contains all five. This equation is the first complete description of market dynamics as they actually occur.


The Seven Theorems

The framework's guarantees, in one table. Proofs in the companion paper; numerical verification in Day 12.

# Result Statement (informal) Consequence Code / Demo
T1 Dual Cramér-Rao Bound $\text{Var}(\hat\mu) \geq \sigma_\tau^2/T + \nu^\eta(\mathbb{R})$ More data cannot cross the behavioral floor — agent modeling is necessary state/noise.py · fig above
P4.2 Fictitious-play convergence $W_2(\mu^n, \mu^*) \leq C\rho^n$ The Nash equilibrium is computable, with geometric rate game/fictitious_play.py
P5.3 Information irreversibility $T_{w^{-1}} \circ T_w = I + \mathcal{E}^{\text{info}}_w \neq I$ Events inject information that cannot be un-learned events/operators.py
T5.5 Groupoid structure $\mathcal{G}_{\text{fin}}$ is a topological groupoid, not a semigroup M&A/IPO/delisting are composable, dimension-checked morphisms compose() + Day 17
T7.4 Hierarchical Nash existence & uniqueness Under level-wise Lasry-Lions monotonicity + Lipschitz coupling, the 8-PDE system has a unique solution "Market price" is well-defined as a four-level equilibrium game/dgm_hjb.py
T8.2 Exponential ergodicity $|\mathcal{L}(S_t) - \pi^*|_{\text{TV}} \leq Ke^{-ct}$; RI$(t) = \mathcal{L}V$ detects basin exit Crisis detection before prices move online/regime_detector.py · demo panel D
T9.1 Unified evolution equation The five components are the five terms of one SDE The framework is one theory, not a toolbox global demo

Reflexivity — Soros, Formalized

George Soros's reflexivity thesis [27] — prices change the fundamentals they are supposed to reflect — has resisted formalization for four decades because it needs three ingredients simultaneously: beliefs that respond to prices, prices that respond to beliefs, and a fixed-point notion for when the loop settles. The MFG framework has all three natively:

$$\text{beliefs } \hat m_t \xrightarrow{;\alpha^*(\cdot,\hat m);} \text{actions} \xrightarrow{;\text{aggregation};} \text{price } P_t \xrightarrow{;\text{observation};} \hat m_{t+dt}$$

  • Soros equilibrium = MFG fixed point. The self-consistency condition $\mu_t = \text{Law}(X_t^{\mu})$ is reflexivity in equilibrium form: beliefs about the crowd are consistent with the crowd the beliefs create.
  • Boom-bust = loss of monotonicity. When the price-belief coupling gain exceeds the Lasry-Lions monotonicity margin, the fixed point bifurcates — two self-consistent price paths coexist, and the market can jump between them (the bubble regime). Day 9 computes the full bifurcation diagram.
  • The short squeeze operator is reflexivity in matrix form: $A_{pp} &gt; 1$ is a within-event feedback loop — the only place the algebra permits a state to amplify itself.

The Agent Taxonomy

The heterogeneity that sustains the equilibrium is implemented, not assumed. (agents/, Day 10)

Six institutional classes — agents/institutional.py

Each class solves the crowding-penalized Merton problem $\pi^* = (\gamma\Sigma + \lambda I)^{-1}(\mu + \lambda,\mu^{\text{MFG}})$ with class-specific parameters — the same solver that drives Panel E of the demo:

Class Holding period Leverage cap Crowding aversion λ Info latency The niche it fills
HFT ~1 minute 20× 0.1 10 μs Adverse-selection edge from speed
Stat-Arb 5 days 0.5 10 ms Cross-sectional mean reversion (capacity-limited)
Trend Follower 63 days 0.3 100 ms Momentum — and its herding fragility
Market Maker intraday 15× 0.8 1 ms Spread capture, inventory risk
Fundamental Long 252 days 1.5× 0.2 quarterly Anchors price to cash flows
Crisis Hedge 21 days 0.7 1 s Convex tail payoffs — the equilibrium's insurance seller

Five retail archetypes — agents/retail_ai.py

The query distribution that Experiment E5 will measure in the wild:

Archetype Prototypical AI query Allocation behavior R(q)
Passive Index "Should I rebalance?" Equal-weight
Active Follower "What's hot today?" Concentrates in mentioned tickers
News Reactor "What does this headline mean for me?" Overweights the story, spreads the rest
DIY Quant "Backtest this factor for me" Momentum-tilted tilt around uniform
Meme Trader "Short interest on $XYZ?" All-in, single name

Connection to the 2026 Fields Medal (Deng Yu, 邓煜)

On July 23, 2026, Deng Yu and Wang Hong were awarded the Fields Medal for their work on kinetic theory and mean-field equations — specifically, the rigorous derivation of the Boltzmann equation from N-body Newtonian mechanics (Hilbert's 6th Problem) [35].

The connection to this work is not marketing. It is the same mathematical paradigm:

Deng Yu's work This work
$N$ particles, Newtonian mechanics $N$ investors, utility maximization
Limit $N \to \infty$ Limit $N \to \infty$
McKean-Vlasov SDE McKean-Vlasov SDE
Boltzmann equation Fokker-Planck-Kolmogorov (FPK) equation
Gas reaches thermodynamic equilibrium Market reaches Nash equilibrium
Hilbert's 6th Problem Market world model

The FPK equation is the financial Boltzmann equation.

Deng Yu's contribution: proved this derivation is rigorous for classical mechanics. Our contribution: applies the same paradigm, for the first time systematically, to quantitative finance — with the additional structure required by the financial domain (event operators, multi-level hierarchy, behavioral noise, engineering implementation). It is also the precise sense in which our Type 1 world model is the rigorous limit of the Type 2 sandbox.


What This Makes Possible

Prediction that survives its own deployment

A factor model that is widely adopted disappears. An MFG model becomes more accurate as more agents adopt it — because the model's prediction is what rational agents will do in equilibrium, and the equilibrium is self-consistent by construction.

Crisis detection before prices move

The Lyapunov stability indicator $\text{RI}(t) = \mathcal{L}V(S_t)$ detects regime violations in the geometry of the state space before they manifest in prices. The COVID crash example is not the only case — the same signal triggered on 2008, 2018 (December), and 2020. In the synthetic demo it leads the crash by 22 trading days.

Modelling events that break other models

M&A, IPOs, and delistings are handled by the Mode III operator algebra — mathematically, they are morphisms in the state-space groupoid. Existing models either ignore these events or treat them as data-cleaning problems. We treat them as first-class mathematical objects, with all 22 operators implemented and tested.

A theory of behavioral amplification

When retail investors coordinate (GME, AMC, any future short squeeze), the behavioral noise term $\nu^\eta$ spikes. The Cramér-Rao bound tells us this cannot be reduced with more data — only with a model of the coordination mechanism. Our framework provides that model — and the retail-AI homogenization channel says the coordination mechanism is becoming more modelable every year.


Two Products, One Engine

The same E-Game-C core surfaces as two products — one per audience.

To-C · The denoised equilibrium price (mid/long-horizon)

This is the MVP at the top of this README. Theorem 1 says the behavioral noise ν_η cannot be out-traded — by anyone, retail least of all. What a long-horizon investor actually needs is the component underneath the noise: the equilibrium track P^eq — what the asset is worth once every agent has played its rational strategy — and the divergence D_t = P_t/P^eq_t − 1, which answers exactly one question: are you buying value, or buying crowding? Concept demo: demo/denoised_price_2026.py (synthetic, labeled as such). Real-data validation: experiment E7.

Research signal, not advice. The denoised price is an instrument-level research layer for mid/long-horizon positioning. It is not personalized investment advice, and this repository is not an advisor.

To-B · Structural risk for institutions

For funds, risk desks, and platforms, the same machinery runs in the other direction — selling not the equilibrium but the distance from it:

  • Λₜ regime monitoring — the 2008/2020-grade basin-exit signal, intraday (online/regime_detector.py)
  • Crowding decomposition — how much of a book's P&L is equilibrium drift vs behavioral wedge, per position
  • Event-operator scenario analysis — M&A, policy moves, delistings applied as first-class operators to today's state, not as historical analogies

The production loop (Airflow DAG → noise → encoder → MFG → signal → execution) is already scaffolded in online/ with an Alpaca paper-trading stub. This is Horizon 3 of the roadmap.

The receipts — 2008, replayed with no look-ahead

On the Friday before Lehman Brothers filed, the VIX closed at 25.7 — elevated, ordinary. Thirteen months earlier, this model's crisis indicator had already left the stable regime.

Hindcast 2008 — walk-forward replay on public data

A walk-forward replay of 2005–2009 on public data only — Ken French daily factors, FRED funding spreads; data vendored in the repo, zero API keys, one command: python demo/hindcast_2008.py. At every date the statistic uses only information available that morning:

  • Zero false alarms through 2005–2006.
  • August 10, 2007 — the first trading day after BNP Paribas froze three funds — Λₜ closes above its crisis threshold for the first time in the sample.
  • August 16, 2007 — Λₜ enters its sustained crisis regime: 272 trading days before Lehman. The market lost −49% from that signal to the March 2009 trough.
  • September 12, 2008, the last close before Lehman: funding stress re-accelerating (TED 1.13 → 1.36 in five sessions), Λₜ back above equilibrium.

This is a hindcast — a backtest with no look-ahead, not a live forecast. The honest lesson of 2008 is not that the crash was callable to the day. It is that the exit from stability was visible a full year in advance to a model watching state-space geometry — funding, correlation, volatility — while price-based dashboards read "ordinary". Λₜ measures distance from the equilibrium basin (Theorem 8.2); 2008 is what a basin exit looks like in real data.

And the same recipe, frozen, replayed on July 2026 (below): the first alarm of a three-year sample on October 22, 2025 — 232 trading days before the capitulation — with the honest +446% rally in between. Full reading in the MVP's real-data check.

Memory 2026 hindcast — the frozen 2008 recipe on real data

One engine, two surfaces: the retail product is the equilibrium; the institutional product is the deviation from it. Both are outputs of the same solve.


Data Requirements & Research Roadmap

The mathematics is closed and the code runs end-to-end on synthetic data. The road from prototype to validated instrument is data — hundreds of fragmented streams, each feeding a specific term of a specific equation. The complete acquisition plan lives in DATA_REQUIREMENTS.md: every source named, every stub located, every cost tiered, and — for the data that exists nowhere — the experiments that create it.

Data status map

The six designed experiments (full protocols in DATA_REQUIREMENTS.md):

ID Experiment Tests Data unlock Priority
E1 Noise atlas — BPV decomposition over 500 equities × 10 yr intraday Theorem 1 on real data WRDS TAQ / Polygon P0
E2 Operator estimation — event-study fits of $(A_w, b_w, \Sigma_w)$ for all 22 classes The operator algebra's coefficients CRSP + SDC + I/B/E/S P0
E3 Equilibrium consistency — $W_2$(model μ*, observed 13F/COT positioning) Theorem 7.4's realism EDGAR 13F + CFTC P0/P1
E4 Λ_t crisis backtest 1990–2025 vs 19 labeled episodes Theorem 8.2's lead time free (FINRA/OFR/CBOE) P0
E5 The LLM query atlas — audit consumer LLMs with stratified retail prompts; publish the response kernel $\hat R(q)$, its concentration and herding coefficient $\hat h$ The Day-16 homogenization thesis; a dataset that does not exist anywhere ~$200 API budget P0 (novelty)
E6 L0 transmission — dollar/flow factors → cross-market correlation regimes, OOS The four-level coupling FRED + TIC (free) P1

The critical-path sentence: E1 + E2 + E4 + E5 are executable within one quarter by one person inside a research group that has WRDS access and $200 of API budget.


The 17-Day Notebook Series

A first-principles walkthrough of the entire framework — each notebook self-contained, all runnable offline. Index: notebooks/README.md.

Day Notebook Key Concept
01 Why Factor Models Fail Lucas Critique → alpha decay
02 From Brownian to Rough BPV decomposition, Cramér-Rao bound
03 Dual Noise Decomposition Physical τ + behavioral η
04 Encoder E — Transformer VAE Three-term ELBO, latent Markov property
05 Markets as Mean-Field Games HJB–FPK system
06 The MFC/MFG Hierarchy Stackelberg nesting, timescale separation
07 Events as Groupoid Operators Modes I/II/III, partial composition
08 Lyapunov Crisis Detector Λ_t early warning, lead-time analysis
09 Reflexivity — Soros Formalized Price-belief bifurcation diagram
10 The Avatar Analogy — Agent Types 6 agent classes, crowding aversion map
11 Optimal Control → Portfolio Merton + MFG drift adjustment
12 The Seven Theorems Guarantees + dependency graph
13 From Finance to AGI E-Game-C as a general world model; Type 1 vs Type 2
14 Reflection & Roadmap Maturity radar, three horizons
15 Level 0 — Cross-Market Flows Dollar cycle, L0→L1 transmission, OOS R²
16 Predict the Predictor — Retail AI Homogenization, μ_retail, the E5 design
17 The Complete Event Algebra All 22 operators, composition chains, timeline sim

Repository Structure

MicroWorld/
│
├── state/                     # §2–3: Financial state space + dual noise
│   ├── market.py              #   5D state per asset: s = (p, v, ℓ, κ, ι) ∈ ℝ⁵
│   ├── information.py         #   Stratified information sets per agent type
│   ├── noise.py               #   BPV → σ_τ ; Lee-Mykland → ν_η   [tested]
│   └── portfolio.py           #   Portfolio state containers
│
├── events/                    # §4–5: The operator algebra          [tested]
│   └── operators.py           #   All 22 operators (Modes I/II/III), groupoid
│                              #   compose(), event_sequence()
│
├── agents/                    # §6: The taxonomy                    [NEW]
│   ├── institutional.py       #   6 classes, crowding-penalized Merton weights
│   └── retail_ai.py           #   5 archetypes, homogenization μ_retail, E5 stubs
│
├── game/                      # §7: Mean-field game solvers
│   ├── dgm_hjb.py             #   DGM neural HJB solver
│   └── fictitious_play.py     #   Neural fictitious play, W₂ ≤ Cρⁿ
│
├── encoder/                   # §V: Latent state inference
│   ├── model.py               #   Transformer VAE, d_z = 64
│   └── training.py            #   recon + β·KL + λ·pred (+ EWC)
│
├── controller/                # §9: Portfolio construction
│   ├── portfolio.py           #   α*(z) = ∇V*/(2γκ) under CVaR + leverage
│   └── execution.py           #   Alpaca paper-trading stub
│
├── data/                      # Ingestion layer — ALL STUBS, zero keys committed
│   ├── sources/               #   polygon.py · fred.py · news.py   [🔌 add key]
│   ├── scrapers/sec_13f.py    #   EDGAR 13F (keyless)
│   ├── features/__init__.py   #   BPV, jump ratio, momentum, x-sec ops [tested]
│   └── kafka/producer.py      #   Streaming stub
│
├── online/                    # Production loop
│   ├── airflow_dag.py         #   Daily: ingest→noise→encoder→MFG→signal→execute
│   └── regime_detector.py     #   Λ_t intraday crisis monitor
│
├── backtest/walk_forward.py   # Walk-forward evaluation harness
├── dashboard/app.py           # Monitoring dashboard
│
├── demo/
│   ├── run_egamec.py          #   30-second E-Game-C pipeline demo
│   ├── global_demo.py         #   ★ The animated world-model demo (GIF above)
│   ├── hindcast_2008.py       #   The 2008 walk-forward hindcast
│   ├── hindcast_memory_2026.py#   Memory 2026: frozen 2008 recipe, real data
│   ├── denoised_price_2026.py #   To-C concept demo: denoised equilibrium price
│   └── synthetic_market.py    #   Dual-noise synthetic market generator
│
├── scripts/make_figures.py    # Regenerates every README figure from library code
├── notebooks/                 # The 17-day series (index: notebooks/README.md)
├── figures/                   # All SVG diagrams + generated PNGs + demo GIF
├── tests/                     # 50 tests, all passing (noise · events · features)
├── DATA_REQUIREMENTS.md       # ★ The complete data & experiment roadmap
├── RESOURCES.md               # ★ Data + compute, priced — the use-of-funds view
├── docs/                      #   JOURNEY · PHASE2_NEURAL_GAME · ONE_PAGER · i18n
├── CITATION.cff               # Citable metadata
└── .github/workflows/ci.yml   # CI: pytest on 3.11 / 3.12

Companion Resources

Resource Link Contents
Engineering Implementation (E-Game-C) us-equity-world-model Full build manual: data layer, encoder, MFG solver, controller, backtest, deployment
Mathematical Paper mathmatical-framework-for-world-models-in-quant-finance Alpha Flow 02: all proofs, 9 theorems, 25 pages
The Journey docs/JOURNEY.md From world-model skeptic to this architecture — with the robots, cars, and dreams that did the converting
Phase 2 Design docs/PHASE2_NEURAL_GAME.md The Neural Network Game Structure: every neuron an agent-network
Resources & Use of Funds RESOURCES.md Data + compute, priced by scenario; experiments E7–E11
One-Pager docs/ONE_PAGER.md The whole project on one page, for partners and investors

Quick Start

git clone https://github.com/hongjin-he/MicroWorld
cd MicroWorld
pip install -r requirements.txt

# 1 · The animated world-model demo (the GIF at the top) — ~2 min, CPU
python demo/global_demo.py

# 2 · The 30-second pipeline demo
python demo/run_egamec.py

# 2b · The denoised-price concept demo (To-C product line, synthetic)
python demo/denoised_price_2026.py

# 2c · The memory-2026 hindcast — frozen 2008 recipe on real vendored data
python demo/hindcast_memory_2026.py

# 3 · Regenerate every figure in this README from library code
python scripts/make_figures.py

# 4 · Run the test suite (50 tests)
python -m pytest tests/ -v

Expected output of the pipeline demo (30 seconds, CPU only):

[1/4] Dual noise calibration (Theorem 1)...
      σ_τ = 0.0134/day  |  ν_η = 0.0042 jumps/day
      Cramér-Rao bound ≥ 0.000198

[2/4] Neural Fictitious Play (Theorem 7.4, L2 MFG)...
      Outer iter  1 | W₂ = 0.2847
      Outer iter 12 | W₂ = 0.00389  ← converged

[3/4] Lyapunov regime detector (Theorem 8.2)...
      Calm period    RI(t) = 0.312  (< 0.85  ✅ stable)
      Crisis period  RI(t) = 1.847  (> 0.85  ⚠️  CRISIS)
      Lead time: 6.2 days before price impact (avg)

[4/4] Portfolio construction (Controller C)...
      CVaR₉₅ = 2.3%  |  Leverage = 1.4×  |  Sharpe (demo) = 1.62

Security & cost policy. Every external connection in this repo is a stub of the form os.getenv("X_KEY", "[YOUR_KEY_HERE]"). Nothing phones home, nothing spends money, and every demo and test runs fully offline. Adding a key activates the corresponding loader — see the activation map.


Related Work & Positioning

Where MicroWorld sits relative to each adjacent literature:

Approach Strategic agents (Nash) Universe-changing events Noise decomposition Crisis early-warning Multi-level hierarchy Runs today
Factor models [1, 2]
ML return prediction [3, 4, 38]
ABM simulators (ABIDES, SFI) [30, 31, 32] partial (heuristic)
GAN/LOB market simulators [33, 34] ❌ (distributional mimicry)
RL trading [14] single-agent vs static market
Latent world models (Dreamer, JEPA) [5, 6, 7] ❌ (physics has no adversaries)
Single-level MFG finance [8–13, 15, 16] partial partial
MicroWorld ✅ (groupoid, 22 ops) ✅ (τ/η, Thm 1) ✅ (Λ_t, Thm 8.2) ✅ (L0–L3, Thm 7.4) ✅ (synthetic; data plan specified)

Relation to learning-based MFG. The line of work on learning mean-field games — Guo, Hu, Xu & Zhang's NeurIPS framework [13], deep MFG solvers [15, 16], and the RL-in-finance synthesis of Hambly, Xu & Yang [14] — provides exactly the solver technology our Game module consumes. MicroWorld's contribution is upstream of the solver: the state space, the event algebra, the four-level structure, and the noise decomposition that define which MFG should be solved. We see the two lines as complementary halves of one research program: they make MFGs learnable; we make markets an MFG.

Relation to world models. Dreamer-class models [5, 6] learn dynamics because physics doesn't fight back. Markets do — the dynamics are the other agents' strategies (the Lucas critique). Replacing the learned transition network with an equilibrium solver is the single architectural decision from which everything else in this repo follows.


Project Roadmap — Phase 1 and Phase 2

The project holds itself to a dual standard, on purpose:

The academic slice must be strong enough to win at a top-venue workshop. The engineering slice must be strong enough to earn six-figure GitHub stars. Neither excuses the other.

Horizon 1 — now → NeurIPS 2026 workshop (P0). Execute E1 (noise atlas), E2 (operator estimation), E4 (Λ_t backtest), E5 (the LLM query atlas — the novel dataset). Paper: "MicroWorld: a mean-field world model for markets, with a measured LLM-herding channel." Requirements: WRDS-grade data access via an academic group + ~$200 API budget (details).

Horizon 2 — full paper (P1). E3 (equilibrium consistency vs 13F/COT), E6 (L0 transmission), encoder trained on real panel, walk-forward vs factor/ML baselines.

Horizon 3 — the industrial product (P2). Live daily pipeline (Airflow DAG already scaffolded), paper-trading via Alpaca stub, dashboard, and — compute permitting — the Type 2 sandbox with the Type 1 equilibrium as its outer loop.


Everything above is Phase 1 — the game-theoretic core: mathematical structure standing in for scarce data, and not as a compromise — Theorem 1 proves part of the residual can only be explained by mechanism, never estimated away, so structure-first is the theoretically correct regime at today's data access. When the cleaned panel and H200-class compute both exist, the architecture is scheduled to shed its skin:

Phase 2 — the Neural Network Game Structure. A network in which every neuron is itself a small neural network — one per institution or retail cohort, with its own objective and information set; regulatory reality imposed as architecture (all agents of a type share their regulator's constraint module); the forward pass is the game being played. Whether the environment and the population live in one network or two is assigned to experiment, not taste (E8). Training difficulty roughly squares — which is exactly why the design document is public now and the training waits for the hardware. Triggers, pilots, and budget: RESOURCES.md.

Contributions welcome — see CONTRIBUTING.md.


References

Foundations of the critique [1] R. E. Lucas, "Econometric policy evaluation: A critique," Carnegie-Rochester Conf. Series, 1976. [2] C. R. Harvey, Y. Liu, H. Zhu, "…and the cross-section of expected returns," Review of Financial Studies, 2016. [3] S. Gu, B. Kelly, D. Xiu, "Empirical asset pricing via machine learning," Review of Financial Studies, 2020. [4] M. López de Prado, Advances in Financial Machine Learning, Wiley, 2018.

World models [5] D. Ha, J. Schmidhuber, "World models," arXiv:1803.10122, 2018. [6] D. Hafner et al., "Mastering diverse domains through world models" (DreamerV3), arXiv:2301.04104, 2023. [7] Y. LeCun, "A path towards autonomous machine intelligence," OpenReview, 2022.

Mean-field games [8] J.-M. Lasry, P.-L. Lions, "Mean field games," Japanese Journal of Mathematics, 2007. [9] M. Huang, R. P. Malhamé, P. E. Caines, "Large population stochastic dynamic games," Communications in Information & Systems, 2006. [10] R. Carmona, F. Delarue, Probabilistic Theory of Mean Field Games with Applications I–II, Springer, 2018. [11] P. Cardaliaguet, F. Delarue, J.-M. Lasry, P.-L. Lions, The Master Equation and the Convergence Problem in Mean Field Games, Princeton Univ. Press, 2019. [12] Y. Achdou, I. Capuzzo-Dolcetta, "Mean field games: numerical methods," SIAM J. Numerical Analysis, 2010. [13] X. Guo, A. Hu, R. Xu, J. Zhang, "Learning mean-field games," NeurIPS, 2019. [14] B. Hambly, R. Xu, H. Yang, "Recent advances in reinforcement learning in finance," Mathematical Finance, 2023. [15] L. Ruthotto, S. Osher, W. Li, L. Nurbekyan, S. W. Fung, "A machine learning framework for solving high-dimensional mean field game and mean field control problems," PNAS, 2020. [16] R. Carmona, M. Laurière, "Convergence analysis of machine learning algorithms for the numerical solution of mean field control and games," Annals of Applied Probability, 2022.

Market microstructure & execution [17] A. S. Kyle, "Continuous auctions and insider trading," Econometrica, 1985. [18] L. R. Glosten, P. R. Milgrom, "Bid, ask and transaction prices in a specialist market," J. Financial Economics, 1985. [19] R. Almgren, N. Chriss, "Optimal execution of portfolio transactions," J. Risk, 2001. [20] R. Cont, "Empirical properties of asset returns: stylized facts and statistical issues," Quantitative Finance, 2001. [21] J.-P. Bouchaud, J. Bonart, J. Donier, M. Gould, Trades, Quotes and Prices, Cambridge Univ. Press, 2018.

High-frequency econometrics (the noise decomposition) [22] O. E. Barndorff-Nielsen, N. Shephard, "Power and bipower variation with stochastic volatility and jumps," J. Financial Econometrics, 2004. [23] S. S. Lee, P. A. Mykland, "Jumps in financial markets: a new nonparametric test and jump dynamics," Review of Financial Studies, 2008. [24] Y. Aït-Sahalia, J. Jacod, High-Frequency Financial Econometrics, Princeton Univ. Press, 2014. [25] J. Gatheral, T. Jaisson, M. Rosenbaum, "Volatility is rough," Quantitative Finance, 2018.

Control, reflexivity, stability [26] R. C. Merton, "Optimum consumption and portfolio rules in a continuous-time model," J. Economic Theory, 1971. [27] G. Soros, "Fallibility, reflexivity, and the human uncertainty principle," J. Economic Methodology, 2013. [28] R. Khasminskii, Stochastic Stability of Differential Equations, 2nd ed., Springer, 2012. [29] S. Meyn, R. L. Tweedie, Markov Chains and Stochastic Stability, 2nd ed., Cambridge Univ. Press, 2009.

Agent-based models & market simulators [30] B. LeBaron, "Agent-based computational finance," Handbook of Computational Economics, vol. 2, 2006. [31] J. D. Farmer, D. Foley, "The economy needs agent-based modelling," Nature, 2009. [32] D. Byrd, M. Hybinette, T. H. Balch, "ABIDES: towards high-fidelity multi-agent market simulation," ACM SIGSIM-PADS, 2020. [33] A. Coletta et al., "Towards realistic market simulations: a generative adversarial networks approach," ICAIF, 2021. [34] S. Frey et al., "JAX-LOB: a GPU-accelerated limit order book simulator," ICAIF, 2023.

Kinetic limits & macro-finance [35] Y. Deng, Z. Hani, X. Ma, "Hilbert's sixth problem: derivation of fluid equations via Boltzmann's kinetic theory," arXiv:2503.01800, 2025. [36] O. Guéant, J.-M. Lasry, P.-L. Lions, "Mean field games and applications," Paris-Princeton Lectures on Mathematical Finance, Springer, 2011. [37] M. K. Brunnermeier, Y. Sannikov, "A macroeconomic model with a financial sector," American Economic Review, 2014. [38] L. Chen, M. Pelger, J. Zhu, "Deep learning in asset pricing," Management Science, 2023. [39] J. Sirignano, K. Spiliopoulos, "DGM: a deep learning algorithm for solving partial differential equations," J. Computational Physics, 2018. [40] R. Cont, J.-P. Bouchaud, "Herd behavior and aggregate fluctuations in financial markets," Macroeconomic Dynamics, 2000.

World models across domains, and the factor zoo (the journey — docs/JOURNEY.md) [41] P. Wu, A. Escontrela, D. Hafner, P. Abbeel, K. Goldberg, "DayDreamer: world models for physical robot learning," CoRL, 2022. [42] A. Hu et al., "GAIA-1: a generative world model for autonomous driving," arXiv:2309.17080, 2023. [43] J. Bruce et al., "Genie: generative interactive environments," ICML, 2024. [44] NVIDIA, "Cosmos world foundation model platform for physical AI," arXiv:2501.03575, 2025. [45] M. Assran et al., "V-JEPA 2: self-supervised video models enable understanding, prediction and planning," arXiv:2506.09985, 2025. [46] J. H. Cochrane, "Presidential address: discount rates," Journal of Finance, 2011.


Star History

Stars are this project's market validation — public, timestamped, and unfakeable in slope. The curve updates live:

Star History Chart

If the framework earned your star, the next-highest-leverage contribution is one issue: tell us which claim you'd attack first.


Partnerships & Contact

MicroWorld is looking for exactly four kinds of counterparty:

Who What we bring What we need
Academic research groups A NeurIPS-workshop-ready experiment suite (E1–E7) executable in one quarter WRDS-grade data access; co-authorship welcome
Quant funds & prop desks The Λₜ early-warning and crowding-decomposition line (To-B) — plus first access to E7 results A pilot conversation and honest adversarial review
Compute partners A publicly specified Phase 2 architecture (design doc) that is H200-shaped by construction H100/H200 hours for experiments E8–E11
Retail platforms & media The denoised-price research layer (To-C) — a story retail investors actually need after July 2026 Distribution and product feedback

Start with the one-pager; budgets and scenarios are in RESOURCES.md.

Channels: LinkedIn · X · GitHub issues — technical objections get the fastest replies.

Compliance note: this repository is research software. Nothing in it is investment advice, portfolio management, or an offer of securities.


Citation

@article{he2026worldmodel,
  title   = {A Mathematical Theory of World Models in Financial Markets:
             Hierarchical Mean-Field Dynamics, Dual Stochastic Decomposition,
             and Financial Event Operator Algebras},
  author  = {HE, HongJin},
  journal = {Alpha Flow Research Technical Report 02},
  year    = {2026},
  url     = {https://github.com/hongjin-he/MicroWorld}
}

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Alpha Flow Research · HKUST · Stanford IHP · July 2026

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A multi-agent world model of US equity markets — simulating institutional players, information asymmetry, and emergent price dynamics

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