OAI/AlgebraicGeometry/StableCoordinate/AllFibers.lean
3 declarations, 0 contain sorry, 0 declared as axioms
Every complex fiber of the exact polynomial
The two explicit quotient-algebra calculations cover every parameter, including zero. Together with the noncoordinate theorem, these equivalences show that every fiber is affine three-space and its embedding is nonrectifiable.
- theorem
OAI.StableCoordinate.all_fibers_isAffineThreeSpaceline 19Source documentation
Every complex fiber of the specified polynomial has the coordinate algebra of affine three-space, with no exceptional parameters.
theorem all_fibers_isAffineThreeSpace : ∀ t : ℂ, IsAffineThreeSpaceFiber t := by … - def
OAI.StableCoordinate.exactFiberEquivline 28Source documentation
An actual complex algebra equivalence for each fiber.
noncomputable def exactFiberEquiv (t : ℂ) : FiberRing t ≃ₐ[ℂ] R 3 := …
Mentions: OAI.StableCoordinate.FiberRing, OAI.StableCoordinate.R
- theorem
OAI.StableCoordinate.fiberPackage_of_noncoordinateline 33Source documentation
With the unrestricted four-variable coordinate obstruction, the already proved all-fiber calculation supplies the entire geometric principal group.
theorem fiberPackage_of_noncoordinate (h : ¬ IsCoordinate (by decide : 0 < 4) f) : FiberPackage := …Mentions: OAI.StableCoordinate.IsCoordinate, OAI.StableCoordinate.f, OAI.StableCoordinate.FiberPackage