MAYBE
0.18/0.23	MAYBE
0.18/0.23	
0.18/0.23	Problem:
0.18/0.23	 active(U11(tt(),N)) -> mark(N)
0.18/0.23	 active(U21(tt(),M,N)) -> mark(s(plus(N,M)))
0.18/0.23	 active(U31(tt())) -> mark(0())
0.18/0.23	 active(U41(tt(),M,N)) -> mark(plus(x(N,M),N))
0.18/0.23	 active(and(tt(),X)) -> mark(X)
0.18/0.23	 active(isNat(0())) -> mark(tt())
0.18/0.23	 active(isNat(plus(V1,V2))) -> mark(and(isNat(V1),isNat(V2)))
0.18/0.23	 active(isNat(s(V1))) -> mark(isNat(V1))
0.18/0.23	 active(isNat(x(V1,V2))) -> mark(and(isNat(V1),isNat(V2)))
0.18/0.23	 active(plus(N,0())) -> mark(U11(isNat(N),N))
0.18/0.23	 active(plus(N,s(M))) -> mark(U21(and(isNat(M),isNat(N)),M,N))
0.18/0.23	 active(x(N,0())) -> mark(U31(isNat(N)))
0.18/0.23	 active(x(N,s(M))) -> mark(U41(and(isNat(M),isNat(N)),M,N))
0.18/0.23	 active(U11(X1,X2)) -> U11(active(X1),X2)
0.18/0.23	 active(U21(X1,X2,X3)) -> U21(active(X1),X2,X3)
0.18/0.23	 active(s(X)) -> s(active(X))
0.18/0.23	 active(plus(X1,X2)) -> plus(active(X1),X2)
0.18/0.23	 active(plus(X1,X2)) -> plus(X1,active(X2))
0.18/0.23	 active(U31(X)) -> U31(active(X))
0.18/0.23	 active(U41(X1,X2,X3)) -> U41(active(X1),X2,X3)
0.18/0.23	 active(x(X1,X2)) -> x(active(X1),X2)
0.18/0.23	 active(x(X1,X2)) -> x(X1,active(X2))
0.18/0.23	 active(and(X1,X2)) -> and(active(X1),X2)
0.18/0.23	 U11(mark(X1),X2) -> mark(U11(X1,X2))
0.18/0.23	 U21(mark(X1),X2,X3) -> mark(U21(X1,X2,X3))
0.18/0.23	 s(mark(X)) -> mark(s(X))
0.18/0.23	 plus(mark(X1),X2) -> mark(plus(X1,X2))
0.18/0.23	 plus(X1,mark(X2)) -> mark(plus(X1,X2))
0.18/0.23	 U31(mark(X)) -> mark(U31(X))
0.18/0.23	 U41(mark(X1),X2,X3) -> mark(U41(X1,X2,X3))
0.18/0.23	 x(mark(X1),X2) -> mark(x(X1,X2))
0.18/0.23	 x(X1,mark(X2)) -> mark(x(X1,X2))
0.18/0.23	 and(mark(X1),X2) -> mark(and(X1,X2))
0.18/0.23	 proper(U11(X1,X2)) -> U11(proper(X1),proper(X2))
0.18/0.23	 proper(tt()) -> ok(tt())
0.18/0.23	 proper(U21(X1,X2,X3)) -> U21(proper(X1),proper(X2),proper(X3))
0.18/0.23	 proper(s(X)) -> s(proper(X))
0.18/0.23	 proper(plus(X1,X2)) -> plus(proper(X1),proper(X2))
0.18/0.23	 proper(U31(X)) -> U31(proper(X))
0.18/0.23	 proper(0()) -> ok(0())
0.18/0.23	 proper(U41(X1,X2,X3)) -> U41(proper(X1),proper(X2),proper(X3))
0.18/0.23	 proper(x(X1,X2)) -> x(proper(X1),proper(X2))
0.18/0.23	 proper(and(X1,X2)) -> and(proper(X1),proper(X2))
0.18/0.23	 proper(isNat(X)) -> isNat(proper(X))
0.18/0.23	 U11(ok(X1),ok(X2)) -> ok(U11(X1,X2))
0.18/0.23	 U21(ok(X1),ok(X2),ok(X3)) -> ok(U21(X1,X2,X3))
0.18/0.23	 s(ok(X)) -> ok(s(X))
0.18/0.23	 plus(ok(X1),ok(X2)) -> ok(plus(X1,X2))
0.18/0.23	 U31(ok(X)) -> ok(U31(X))
0.18/0.23	 U41(ok(X1),ok(X2),ok(X3)) -> ok(U41(X1,X2,X3))
0.18/0.23	 x(ok(X1),ok(X2)) -> ok(x(X1,X2))
0.18/0.23	 and(ok(X1),ok(X2)) -> ok(and(X1,X2))
0.18/0.23	 isNat(ok(X)) -> ok(isNat(X))
0.18/0.23	 top(mark(X)) -> top(proper(X))
0.18/0.23	 top(ok(X)) -> top(active(X))
0.18/0.23	
0.18/0.23	Proof:
0.18/0.23	 Open
0.18/0.24	EOF