fact: Definition s_of_pq' (p q : {i01 R}) : {i01 R} := (`1- (`1-(p%:inum) * `1-(q%:inum)))%:i01.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(interval) mathcomp(mathcomp_extra boolp) signed