Theorems · Theorem · combinatorics

Finset.pi_insert

∀ {α : Type u_1} {β : α → Type u} [inst : DecidableEq α] [inst_1 : (a : α) → DecidableEq (β a)] {s : Finset α}
  {t : (a : α) → Finset (β a)} {a : α},
  a ∉ s → (insert a s).pi t = (t a).biUnion fun b => Finset.image (Finset.Pi.cons s a b) (s.pi t)

Defined in

Mathlib.Data.Finset.Pi

Cited by

1 results in Mathlib

Foundations

Depth 74 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

DecidableEqDecidableEq