MAYBE
Input TRS:
    1: f(x,x) -> c()
    2: a() -> b()
    3: b() -> a()
Infeasibility test:
    f(a(),c()) --> f(x,x)
Co-Order(NegReal,≥,Sum) ...Co-QLPOpS ...Co-QWPOpS(PosReal,>,Sum) ...Co-Order(PosReal,≥,Sum-Sum; PosReal,≥,Sum-Sum) ...failed.