derangements.derangementsRecursionEquiv

{α : Type u_1} → [DecidableEq α] → ↑(derangements (Option α)) ≃ (a : α) × (↑(derangements ↑{a}ᶜ) ⊕ ↑(derangements α))

The set of derangements on Option α is equivalent to the union over all a : α of "derangements on α ⊕ derangements on {a}ᶜ".

Defined in: Mathlib.Combinatorics.Derangements.Basic
Cited by: 1 results in Mathlib
Foundations: Depth 37 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: DecidableEq

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