fact: Hypothesis Hfvmon2: forall a b, fv (a ⊗ b)%CM ≡ (fv a ⊗ fv b)%CM.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)