Theorems · Theorem · combinatorics
Sym2.natCard
∀ (α : Type u_1), Nat.card (Sym2 α) = (Nat.card α + 1).choose 2
Type stars and bars for the case n = 2.
- Defined in
- Mathlib.Data.Sym.NatCard
- Cited by
- 0 results in Mathlib
- Foundations
- Depth 94 from the axioms · uses propext, Classical.choice, Quot.sound
Around this declaration
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Cites14
Mathlib declarations this one mentions in its statement or cites explicitly in its proof. Plumbing is filtered out.
- Fintypeproof · cited by 7,736
- Finiteproof · cited by 3,029
- zero_addproof · cited by 2,366
- Nat.cardstatement · cited by 844
- Sym2statement · cited by 737
- Nat.choosestatement and proof · cited by 494
- Infiniteproof · cited by 352
- nonempty_fintypeproof · cited by 261
- Nat.card_eq_fintype_cardproof · cited by 200
- Classical.decEqproof · cited by 134
- finite_or_infiniteproof · cited by 50
- Nat.card_eq_zero_of_infiniteproof · cited by 46
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