The Koras-Russell cylinder as an affine modification of A^4 — a commuting square through a motivic 4-sphere, a one-point Borel-Moore defect, and a machine-certified verification layer anyone can re-run in one command
computer-algebra motivic-homotopy-theory certified-computation affine-algebraic-geometry koras-russell affine-modification locally-nilpotent-derivation zariski-cancellation borel-moore-homology
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Updated
Aug 1, 2026 - Python