proposition: Fact Re_is_additive : additive Re.
proof: Proof. by move=> x y; rewrite !ReE rmorphB addrACA -opprD mulrBl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)