proposition: Lemma f1' (x : set A) (gX : g @` setT `<=` x `|` y) (ge : forall i : 'I_n, (x (g i)) /\ (~ y (g i)) -> e i = 0) : (\sum_(i < n) f i = 1).
proof: Proof. rewrite /f -(FDist.f1 e) /=; apply eq_bigr => i _; rewrite ffunE. case: ifPn => // /negP; rewrite in_setE => giy. rewrite ge //. have : (x `|` y) (g i) by apply/gX; by exists i. by case. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg fingroup perm matrix) mathcomp(mathcomp_extra boolp classical_sets Rstruct) mathcomp(ssrnum ereal) mathcomp(lra Rstruct reals) Reals ssrR Reals_ext Ranalysis_ext ssr_ext ssralg_ext logb realType_ext fdist