fact: Definition connectable_N r1 r2 := match unifiable_N r1 r2 with | None => false | Some (_, nil) => true | _ => hd_eq (rhs r1) (lhs r2) end.
imports: Coq(Lia Compare_dec) CoLoR(ADecomp AUnif ARenCap ATrs ListUtil RelUtil AGraph LogicUtil AShift ACalls BoolUtil ADuplicateSymb ListDec EqUtil AHDE)