fact: Definition h2lower {A: UU} {n: nat} {v: vec A n} {P: A → UU} {h1v: hvec (vec_map P v)} {Q: A → UU} (h2v: hvec (h1map_vec (λ a _, Q a) h1v)) : hvec (vec_map Q v).
imports: UniMath.Foundations.All UniMath.Combinatorics.StandardFiniteSets UniMath.Combinatorics.Vectors