proposition: Lemma add2O (F : filter_on T) (f g : T -> V) (e : T -> W) : f =O_F e -> g =O_F e -> f + g =O_F e.
proof: Proof. by move=> -> ->; rewrite addO. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum) mathcomp(mathcomp_extra boolp classical_sets functions) ereal reals signed topology normedtype prodnormedzmodule