fact: Definition derivE := Eval lazy beta delta [morphism_2 morphism_1] in (derivZ, deriv_mulC, derivC, derivX, derivMXaddC, derivXsubC, derivM, derivB, derivD, derivN, derivXn, derivM, derivMn).
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)