proposition: Lemma tail_poly_add {R: ringType} (q1 q2: {poly R}): tail_poly (q1 + q2) = tail_poly q1 + tail_poly q2.
proof: Proof. apply coef_poly_eq => i. by rewrite coefD !coef_Poly !nth_behead coefD. Qed.
imports: Relational(OrderEnrichedCategory GenericRulesSimple) mathcomp(all_ssreflect all_algebra reals distr realsum ssrnat ssreflect ssrfun ssrbool ssrnum eqtype choice seq) Mon(SPropBase) Crypt(Axioms ChoiceAsOrd SubDistr Couplings UniformDistrLemmas FreeProbProg Theta_dens RulesStateProb pkg_core_definition choice_type pkg_composition pkg_rhl Package Prelude) extructures(ord fset fmap) Equations(Equations)