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Theorems · Theorem · category theory

CategoryTheory.PreGaloisCategory.card_aut_le_card_fiber_of_connected

∀ {C : Type u₁} [inst : CategoryTheory.Category.{u₂, u₁} C] (F : CategoryTheory.Functor C FintypeCat)
  [inst_1 : CategoryTheory.PreGaloisCategory C] [CategoryTheory.PreGaloisCategory.FiberFunctor F] (A : C)
  [CategoryTheory.PreGaloisCategory.IsConnected A], Nat.card (CategoryTheory.Aut A) ≤ Nat.card (F.obj A).obj

If A is connected, the cardinality of Aut A is smaller than the cardinality of the fiber of A.

Defined in
Mathlib.CategoryTheory.Galois.Basic
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Foundations
Depth 95 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
CategoryTheory.CategoryCategoryTheory.PreGaloisCategoryCategoryTheory.PreGaloisCategory.FiberFunctorCategoryTheory.PreGaloisCategory.IsConnected

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