fact: Definition inv_morph_axiom (f : morphism V D) := forall (a : U) (b1 b2 : V), valid a -> D a Unit -> f a = b1 \+ b2 -> exists a1 a2, [/\ a = a1 \+ a2, valid (a1 \+ a2), D a1 a2, f a1 = b1 & f a2 = b2 ].
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(eqtype) pcm(options axioms prelude) pcm(pcm morphism)