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Theorems · Definition · algebraic geometry

Algebra.IsUnramifiedAt

(R : Type u_1) →
  {A : Type u_2} → [inst : CommRing R] → [inst_1 : CommRing A] → [Algebra R A] → (q : Ideal A) → [q.IsPrime] → Prop

We say that an R-algebra A is unramified at a prime q of A if A_q is formally unramified over R. If A is of finite type over R and q is lying over p, then this is equivalent to κ(q)/κ(p) being separable and pA_q = qA_q. See Algebra.isUnramifiedAt_iff_map_eq in RingTheory.Unramified.LocalRing

Defined in
Mathlib.RingTheory.Unramified.Locus
Cited by
35 results in Mathlib
Foundations
Depth 45 from the axioms · uses propext, Quot.sound
Assumes
CommRingCommRingAlgebraIdeal.IsPrime

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