YES

Problem:
 a() -> g(c())
 g(a()) -> b()
 f(g(X),b()) -> f(a(),X)

Proof:
 DP Processor:
  DPs:
   a#() -> g#(c())
   f#(g(X),b()) -> a#()
   f#(g(X),b()) -> f#(a(),X)
  TRS:
   a() -> g(c())
   g(a()) -> b()
   f(g(X),b()) -> f(a(),X)
  Usable Rule Processor:
   DPs:
    a#() -> g#(c())
    f#(g(X),b()) -> a#()
    f#(g(X),b()) -> f#(a(),X)
   TRS:
    a() -> g(c())
   CDG Processor:
    DPs:
     a#() -> g#(c())
     f#(g(X),b()) -> a#()
     f#(g(X),b()) -> f#(a(),X)
    TRS:
     a() -> g(c())
    graph:
     f#(g(X),b()) -> a#() -> a#() -> g#(c())
    Restore Modifier:
     DPs:
      a#() -> g#(c())
      f#(g(X),b()) -> a#()
      f#(g(X),b()) -> f#(a(),X)
     TRS:
      a() -> g(c())
      g(a()) -> b()
      f(g(X),b()) -> f(a(),X)
     SCC Processor:
      #sccs: 0
      #rules: 0
      #arcs: 1/9