fact: Definition part X := All1 (Leq 0 X.+1 --> (\or_(q \in A) (Incl 0 (rank q).+1 :/\: \and_(q' \in [pred x | q != x]) Not (Incl 0 (rank q').+1)))).
imports: mathcomp(all_ssreflect) RegLang(misc languages dfa nfa regexp)