proposition: Lemma Convn_perm (n : nat) (d : {fdist 'I_n}) (g : 'I_n -> T) (s : 'S_n) : <|>_d g = <|>_(fdistI_perm d s) (g \o s).
proof: Proof. apply S1_inj; rewrite !S1_Convn (ssum_perm _ s). by apply eq_bigr => i _; rewrite fdistI_permE. 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