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Theorems · Theorem · algebraic geometry

AlgebraicGeometry.Etale.of_comp

∀ {X Y : AlgebraicGeometry.Scheme} (f : X ⟶ Y) {Z : AlgebraicGeometry.Scheme} (g : Y ⟶ Z)
  [AlgebraicGeometry.Etale (CategoryTheory.CategoryStruct.comp f g)] [AlgebraicGeometry.LocallyOfFiniteType g]
  [AlgebraicGeometry.FormallyUnramified g], AlgebraicGeometry.Etale f

If f ≫ g is étale and g unramified, then f is étale.

Defined in
Mathlib.AlgebraicGeometry.Morphisms.Etale
Cited by
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Foundations
Depth 196 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
AlgebraicGeometry.EtaleAlgebraicGeometry.LocallyOfFiniteTypeAlgebraicGeometry.FormallyUnramified

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