fact: Definition dfa_op := {| dfa_s := (dfa_s A1, dfa_s A2); dfa_fin := [set q | op (q.1 \in dfa_fin A1) (q.2 \in dfa_fin A2)]; dfa_trans x a := (dfa_trans x.1 a, dfa_trans x.2 a) |}.
imports: mathcomp(all_ssreflect) RegLang(misc languages)