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