fact: Definition fin_transpose_last_two (n : nat) : Fin n.+2 <~> Fin n.+2 := ((equiv_sum_assoc _ _ _)^-1) oE (1 +E (equiv_sum_symm _ _)) oE (equiv_sum_assoc _ _ _).
imports: Basics Types HSet Spaces.Nat.Core Equiv.PathSplit