fact: Fixpoint nn_to_n_merge1 l1:= if l1 is a::l then a:: false:: (nn_to_n_merge1 l) else nil.
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)