proposition: Fact pair_scaleDr : right_distributive scale_pair +%R.
proof: Proof. by move=> a u v; congr (_, _); apply: scalerDr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)