fact: Fixpoint convergent_rec (f:nat -> rat) a b n := if n is n1.+1 then if n1 is n2.+1 then (f n2) * (convergent_rec f a b n1) + (convergent_rec f a b n2) else b else a.
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)