proposition: Fact pickR_some P n x : pickR P n = Some x -> P x.
proof: Proof. by rewrite /pickR; case: (boolP (P _)) => // Px [<-]. Qed.
imports: Rdefinitions Raxioms RIneq Rbasic_fun Zwf Epsilon FunctionalExtensionality Ranalysis1 Rsqrt_def Rtrigo1 Reals mathcomp(all_ssreflect ssralg poly mxpoly ssrnum) HB(structures)