fact: Fixpoint wbase2 (l: seq 'I_3) := if l is a :: l' then a + (wbase2 l').*2 else 0.
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)