Geometry and topology · Oct 6, 2026

Zariski cancellation and affine fibrations over the complex numbers

Constructs an integral complex affine fourfold X≇A4X\not\cong\mathbb A^4 with X×A1≅A5X\times\mathbb A^1\cong\mathbb A^5, disproving affine-space cancellation over ℂ in dimension four. It also disproves the Dolgachev–Weisfeiler affine-fibration conjecture: smooth surjections X→A1X\to\mathbb A^1 and A5→A2\mathbb A^5\to\mathbb A^2 have every residue-field fiber isomorphic to affine three-space but are not Zariski-locally trivial.

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