proposition: Lemma Convn_proj n (g : 'I_n -> T) (d : {fdist 'I_n}) i : d i = R1 -> <|>_d g = g i.
proof: Proof. move=> Hd; apply: S1_inj. rewrite S1_Convn (bigD1 i)//=. rewrite big1; first by rewrite addpt0 Hd scale1pt. move=> j Hj. by move/eqP/fdist1P: Hd => -> //; rewrite scale0pt. 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