proposition: Lemma fgaddE g1 g2 k : (fgadd g1 g2)@_k = g1@_k + g2@_k.
proof: Proof. rewrite mcoeffE in_fsetE. by case: (msuppP g1); case: (msuppP g2); rewrite ?addr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap