%%%%%%%%%%%%%%%%%%  append/3   %%%%%%%%%%%%%%%%%%%%%%%

term(list([]),[]).
term(list([X|Y]),[item(X),list(Y)]).

literal(append(X,Y,Z),[list(X),list(Y),list(Z)]).

bg([]).

query2(Clauses):-
	induce_spec([+append([],[b,c],[b,c]),
	             -append([],[a,b],[c,d]),
	             -append([a,b],[c,d],[c,d]),
	             -append([a],[b,c],[d,b,c]),
	             -append([a],[b,c],[a,d,e]),
	             +append([a],[b,c],[a,b,c])
	            ],Clauses).