YES
Input TRS:
    1: a() -> b()
    2: a() -> c()
    3: b() -> c() | b() --> c()
Infeasibility test:
    b() --> c()
Co-Order(NegReal,≥,Sum) ... succeeded.
     a()	weight: 0
     b()	weight: (- (/ 1 2))
     c()	weight: 0
    #(x1)	weight: x1