Theorems · Theorem · combinatorics

Multiset.count_filter

∀ {α : Type u_1} [inst : DecidableEq α] {p : α → Prop} [inst_1 : DecidablePred p] {a : α} {s : Multiset α},
  Multiset.count a (Multiset.filter p s) = if p a then Multiset.count a s else 0

Defined in

Mathlib.Data.Multiset.Filter

Cited by

3 results in Mathlib

Foundations

Depth 22 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

DecidableEqDecidablePred