fact: Definition flattenStep' {X n} (m : stn (S n) → nat) (x : ∏ i : stn (S n), stn (m i) → X) (m' := m ∘ dni lastelement) (x' := x ∘ dni lastelement) : flatten' x = concatenate' (flatten' x') (x lastelement).
imports: UniMath.Combinatorics.FiniteSets UniMath.Combinatorics.Lists UniMath.Combinatorics.Vectors UniMath.MoreFoundations.PartA UniMath.MoreFoundations.Tactics