fact: Definition tuple_padl n k (l: n.-tuple 'I_3) := (l ++ (nseq (k - n) ord0)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype order bigop ssralg) mathcomp(div ssrnum ssrint rat prime path binomial) mathcomp(tuple finset) gaia(fibm)