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Theorems · Theorem · combinatorics

Sym2.card_toFinset_of_not_isDiag

∀ {α : Type u_1} [inst : DecidableEq α] (z : Sym2 α), ¬z.IsDiag → z.toFinset.card = 2

Mapping an unordered pair off the diagonal to a finite set produces a finset of size 2.

Defined in
Mathlib.Data.Sym.Sym2
Cited by
2 results in Mathlib
Foundations
Depth 78 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
DecidableEq

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