MAYBE
0.17/0.20	MAYBE
0.17/0.20	
0.17/0.20	Problem:
0.17/0.20	 active(and(tt(),X)) -> mark(X)
0.17/0.20	 active(plus(N,0())) -> mark(N)
0.17/0.20	 active(plus(N,s(M))) -> mark(s(plus(N,M)))
0.17/0.20	 active(x(N,0())) -> mark(0())
0.17/0.20	 active(x(N,s(M))) -> mark(plus(x(N,M),N))
0.17/0.20	 active(and(X1,X2)) -> and(active(X1),X2)
0.17/0.20	 active(plus(X1,X2)) -> plus(active(X1),X2)
0.17/0.20	 active(plus(X1,X2)) -> plus(X1,active(X2))
0.17/0.20	 active(s(X)) -> s(active(X))
0.17/0.20	 active(x(X1,X2)) -> x(active(X1),X2)
0.17/0.20	 active(x(X1,X2)) -> x(X1,active(X2))
0.17/0.20	 and(mark(X1),X2) -> mark(and(X1,X2))
0.17/0.20	 plus(mark(X1),X2) -> mark(plus(X1,X2))
0.17/0.20	 plus(X1,mark(X2)) -> mark(plus(X1,X2))
0.17/0.20	 s(mark(X)) -> mark(s(X))
0.17/0.20	 x(mark(X1),X2) -> mark(x(X1,X2))
0.17/0.20	 x(X1,mark(X2)) -> mark(x(X1,X2))
0.17/0.20	 proper(and(X1,X2)) -> and(proper(X1),proper(X2))
0.17/0.20	 proper(tt()) -> ok(tt())
0.17/0.20	 proper(plus(X1,X2)) -> plus(proper(X1),proper(X2))
0.17/0.20	 proper(0()) -> ok(0())
0.17/0.20	 proper(s(X)) -> s(proper(X))
0.17/0.20	 proper(x(X1,X2)) -> x(proper(X1),proper(X2))
0.17/0.20	 and(ok(X1),ok(X2)) -> ok(and(X1,X2))
0.17/0.20	 plus(ok(X1),ok(X2)) -> ok(plus(X1,X2))
0.17/0.20	 s(ok(X)) -> ok(s(X))
0.17/0.20	 x(ok(X1),ok(X2)) -> ok(x(X1,X2))
0.17/0.20	 top(mark(X)) -> top(proper(X))
0.17/0.20	 top(ok(X)) -> top(active(X))
0.17/0.20	
0.17/0.20	Proof:
0.17/0.20	 Open
0.17/0.20	EOF