fact: Record def (nz : nullity) (cond : reality) := Def { r :> T; #[canonical=no] P : (nz ==> (r != x0)) && reality_cond cond r }.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(mathcomp_extra)