proposition: Lemma biglub_setU (I J : neset L) : |_| (I `|` J)%:ne = |_| [set |_| I; |_| J]%:ne.
proof: Proof. rewrite nesetU_bigcup biglub_bignesetU; congr (|_| _%:ne); apply/neset_ext => /=. by rewrite image_id /= image_setU !image_set1. Qed.
imports: HB(structures) Reals mathcomp(all_ssreflect ssralg ssrnum) mathcomp(mathcomp_extra boolp classical_sets Rstruct reals) mathcomp(finmap) Reals_ext realType_ext classical_sets_ext ssrR fdist fsdist convex