MAYBE MAYBE TRS: { mark(adx(X)) -> active(adx(mark(X))), mark(zeros()) -> active(zeros()), mark(nats()) -> active(nats()), mark(cons(X1, X2)) -> active(cons(X1, X2)), mark(0()) -> active(0()), mark(s(X)) -> active(s(X)), mark(incr(X)) -> active(incr(mark(X))), mark(hd(X)) -> active(hd(mark(X))), mark(tl(X)) -> active(tl(mark(X))), adx(mark(X)) -> adx(X), adx(active(X)) -> adx(X), active(adx(cons(X, Y))) -> mark(incr(cons(X, adx(Y)))), active(zeros()) -> mark(cons(0(), zeros())), active(nats()) -> mark(adx(zeros())), active(incr(cons(X, Y))) -> mark(cons(s(X), incr(Y))), active(hd(cons(X, Y))) -> mark(X), active(tl(cons(X, Y))) -> mark(Y), cons(X1, mark(X2)) -> cons(X1, X2), cons(X1, active(X2)) -> cons(X1, X2), cons(mark(X1), X2) -> cons(X1, X2), cons(active(X1), X2) -> cons(X1, X2), s(mark(X)) -> s(X), s(active(X)) -> s(X), incr(mark(X)) -> incr(X), incr(active(X)) -> incr(X), hd(mark(X)) -> hd(X), hd(active(X)) -> hd(X), tl(mark(X)) -> tl(X), tl(active(X)) -> tl(X) } DUP: We consider a non-duplicating system. Trs: { mark(adx(X)) -> active(adx(mark(X))), mark(zeros()) -> active(zeros()), mark(nats()) -> active(nats()), mark(cons(X1, X2)) -> active(cons(X1, X2)), mark(0()) -> active(0()), mark(s(X)) -> active(s(X)), mark(incr(X)) -> active(incr(mark(X))), mark(hd(X)) -> active(hd(mark(X))), mark(tl(X)) -> active(tl(mark(X))), adx(mark(X)) -> adx(X), adx(active(X)) -> adx(X), active(adx(cons(X, Y))) -> mark(incr(cons(X, adx(Y)))), active(zeros()) -> mark(cons(0(), zeros())), active(nats()) -> mark(adx(zeros())), active(incr(cons(X, Y))) -> mark(cons(s(X), incr(Y))), active(hd(cons(X, Y))) -> mark(X), active(tl(cons(X, Y))) -> mark(Y), cons(X1, mark(X2)) -> cons(X1, X2), cons(X1, active(X2)) -> cons(X1, X2), cons(mark(X1), X2) -> cons(X1, X2), cons(active(X1), X2) -> cons(X1, X2), s(mark(X)) -> s(X), s(active(X)) -> s(X), incr(mark(X)) -> incr(X), incr(active(X)) -> incr(X), hd(mark(X)) -> hd(X), hd(active(X)) -> hd(X), tl(mark(X)) -> tl(X), tl(active(X)) -> tl(X) } Fail