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