MAYBE
Input TRS:
    1: even(0()) -> true()
    2: even(s(x)) -> false() | odd(x) --> false()
    3: even(s(x)) -> true() | odd(x) --> true()
    4: odd(0()) -> false()
    5: odd(s(x)) -> false() | even(x) --> false()
    6: odd(s(x)) -> true() | even(x) --> true()
Infeasibility test:
    odd(x1) --> false()
    odd(x1) --> true()
Co-Order(NegReal,≥,Sum) ...Co-QLPOpS ...Co-QWPOpS(PosReal,>,Sum) ...Co-Order(PosReal,≥,Sum-Sum; PosReal,≥,Sum-Sum) ...failed.