fact: Variables (ret : idfun ~~> F) (join : F \o F ~~> F).
imports: ssrmatching Reals JMeq mathcomp(all_ssreflect ssralg ssrnum) mathcomp(mathcomp_extra Rstruct reals) infotheo(Reals_ext) infotheo(realType_ext) monae_lib HB(structures)