AlgebraicCurves.Foundations.CommutativeAlgebra.Proofs.HenselianLocalRing_of_moduleFinite_of_isLocalRing.HensFinAux.main
A finite local algebra over a henselian local ring lifts simple roots of monic polynomials.
Source context 7 commands
Surrounding namespaces, section variables, and local commands at this declaration.
section ProofImplementation
namespace AlgebraicCurves.Foundations.CommutativeAlgebra.Proofs
namespace HenselianLocalRing_of_moduleFinite_of_isLocalRing
universe u v
namespace HensFinAux
open IsLocalRing Polynomial
open _root_.HenselianLocalRing
(exists_completeOrthogonalIdempotents_forall_isLocalRing_quotient_of_moduleFinite)Lean source · statement
theorem main (R : Type u) [CommRing R] [HenselianLocalRing R]
{S : Type v} [CommRing S] [IsLocalRing S] [Algebra R S] [Module.Finite R S]
(f : S[X]) (hf : f.Monic) (a₀ : S) (h₁ : f.eval a₀ ∈ maximalIdeal S)
(h₂ : IsUnit (f.derivative.eval a₀)) : ∃ a : S, f.IsRoot a ∧ a - a₀ ∈ maximalIdeal S