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Theorems · Definition · combinatorics

Finset.HasAntidiagonal.sigmaAntidiagonalEquivProd

{A : Type u_1} →
  [inst : AddMonoid A] →
    [inst_1 : Finset.HasAntidiagonal A] → (n : A) × ↥(Finset.HasAntidiagonal.antidiagonal n) ≃ A × A

The disjoint union of antidiagonals Σ (n : A), antidiagonal n is equivalent to the product A × A. This is such an equivalence, obtained by mapping (n, (k, l)) to (k, l).

Defined in
Mathlib.Algebra.Order.Antidiag.Prod
Cited by
5 results in Mathlib
Foundations
Depth 56 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
AddMonoidFinset.HasAntidiagonal

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