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