MAYBE

Problem:
 active(f(f(a()))) -> mark(c(f(g(f(a())))))
 mark(f(X)) -> active(f(mark(X)))
 mark(a()) -> active(a())
 mark(c(X)) -> active(c(X))
 mark(g(X)) -> active(g(mark(X)))
 f(mark(X)) -> f(X)
 f(active(X)) -> f(X)
 c(mark(X)) -> c(X)
 c(active(X)) -> c(X)
 g(mark(X)) -> g(X)
 g(active(X)) -> g(X)

Proof:
 DP Processor:
  DPs:
   active#(f(f(a()))) -> g#(f(a()))
   active#(f(f(a()))) -> f#(g(f(a())))
   active#(f(f(a()))) -> c#(f(g(f(a()))))
   active#(f(f(a()))) -> mark#(c(f(g(f(a())))))
   mark#(f(X)) -> mark#(X)
   mark#(f(X)) -> f#(mark(X))
   mark#(f(X)) -> active#(f(mark(X)))
   mark#(a()) -> active#(a())
   mark#(c(X)) -> active#(c(X))
   mark#(g(X)) -> mark#(X)
   mark#(g(X)) -> g#(mark(X))
   mark#(g(X)) -> active#(g(mark(X)))
   f#(mark(X)) -> f#(X)
   f#(active(X)) -> f#(X)
   c#(mark(X)) -> c#(X)
   c#(active(X)) -> c#(X)
   g#(mark(X)) -> g#(X)
   g#(active(X)) -> g#(X)
  TRS:
   active(f(f(a()))) -> mark(c(f(g(f(a())))))
   mark(f(X)) -> active(f(mark(X)))
   mark(a()) -> active(a())
   mark(c(X)) -> active(c(X))
   mark(g(X)) -> active(g(mark(X)))
   f(mark(X)) -> f(X)
   f(active(X)) -> f(X)
   c(mark(X)) -> c(X)
   c(active(X)) -> c(X)
   g(mark(X)) -> g(X)
   g(active(X)) -> g(X)
  ADG Processor:
   DPs:
    active#(f(f(a()))) -> g#(f(a()))
    active#(f(f(a()))) -> f#(g(f(a())))
    active#(f(f(a()))) -> c#(f(g(f(a()))))
    active#(f(f(a()))) -> mark#(c(f(g(f(a())))))
    mark#(f(X)) -> mark#(X)
    mark#(f(X)) -> f#(mark(X))
    mark#(f(X)) -> active#(f(mark(X)))
    mark#(a()) -> active#(a())
    mark#(c(X)) -> active#(c(X))
    mark#(g(X)) -> mark#(X)
    mark#(g(X)) -> g#(mark(X))
    mark#(g(X)) -> active#(g(mark(X)))
    f#(mark(X)) -> f#(X)
    f#(active(X)) -> f#(X)
    c#(mark(X)) -> c#(X)
    c#(active(X)) -> c#(X)
    g#(mark(X)) -> g#(X)
    g#(active(X)) -> g#(X)
   TRS:
    active(f(f(a()))) -> mark(c(f(g(f(a())))))
    mark(f(X)) -> active(f(mark(X)))
    mark(a()) -> active(a())
    mark(c(X)) -> active(c(X))
    mark(g(X)) -> active(g(mark(X)))
    f(mark(X)) -> f(X)
    f(active(X)) -> f(X)
    c(mark(X)) -> c(X)
    c(active(X)) -> c(X)
    g(mark(X)) -> g(X)
    g(active(X)) -> g(X)
   graph:
    mark#(g(X)) -> mark#(X) -> mark#(f(X)) -> mark#(X)
    mark#(g(X)) -> mark#(X) -> mark#(f(X)) -> f#(mark(X))
    mark#(g(X)) -> mark#(X) -> mark#(f(X)) -> active#(f(mark(X)))
    mark#(g(X)) -> mark#(X) -> mark#(a()) -> active#(a())
    mark#(g(X)) -> mark#(X) -> mark#(c(X)) -> active#(c(X))
    mark#(g(X)) -> mark#(X) -> mark#(g(X)) -> mark#(X)
    mark#(g(X)) -> mark#(X) -> mark#(g(X)) -> g#(mark(X))
    mark#(g(X)) -> mark#(X) -> mark#(g(X)) -> active#(g(mark(X)))
    mark#(g(X)) -> g#(mark(X)) -> g#(mark(X)) -> g#(X)
    mark#(g(X)) -> g#(mark(X)) -> g#(active(X)) -> g#(X)
    mark#(f(X)) -> mark#(X) -> mark#(f(X)) -> mark#(X)
    mark#(f(X)) -> mark#(X) -> mark#(f(X)) -> f#(mark(X))
    mark#(f(X)) -> mark#(X) -> mark#(f(X)) -> active#(f(mark(X)))
    mark#(f(X)) -> mark#(X) -> mark#(a()) -> active#(a())
    mark#(f(X)) -> mark#(X) -> mark#(c(X)) -> active#(c(X))
    mark#(f(X)) -> mark#(X) -> mark#(g(X)) -> mark#(X)
    mark#(f(X)) -> mark#(X) -> mark#(g(X)) -> g#(mark(X))
    mark#(f(X)) -> mark#(X) -> mark#(g(X)) -> active#(g(mark(X)))
    mark#(f(X)) -> f#(mark(X)) -> f#(mark(X)) -> f#(X)
    mark#(f(X)) -> f#(mark(X)) -> f#(active(X)) -> f#(X)
    mark#(f(X)) -> active#(f(mark(X))) ->
    active#(f(f(a()))) -> g#(f(a()))
    mark#(f(X)) -> active#(f(mark(X))) ->
    active#(f(f(a()))) -> f#(g(f(a())))
    mark#(f(X)) -> active#(f(mark(X))) ->
    active#(f(f(a()))) -> c#(f(g(f(a()))))
    mark#(f(X)) -> active#(f(mark(X))) ->
    active#(f(f(a()))) -> mark#(c(f(g(f(a())))))
    c#(mark(X)) -> c#(X) -> c#(mark(X)) -> c#(X)
    c#(mark(X)) -> c#(X) -> c#(active(X)) -> c#(X)
    c#(active(X)) -> c#(X) -> c#(mark(X)) -> c#(X)
    c#(active(X)) -> c#(X) -> c#(active(X)) -> c#(X)
    f#(mark(X)) -> f#(X) -> f#(mark(X)) -> f#(X)
    f#(mark(X)) -> f#(X) -> f#(active(X)) -> f#(X)
    f#(active(X)) -> f#(X) -> f#(mark(X)) -> f#(X)
    f#(active(X)) -> f#(X) -> f#(active(X)) -> f#(X)
    g#(mark(X)) -> g#(X) -> g#(mark(X)) -> g#(X)
    g#(mark(X)) -> g#(X) -> g#(active(X)) -> g#(X)
    g#(active(X)) -> g#(X) -> g#(mark(X)) -> g#(X)
    g#(active(X)) -> g#(X) -> g#(active(X)) -> g#(X)
    active#(f(f(a()))) -> mark#(c(f(g(f(a()))))) -> mark#(c(X)) -> active#(c(X))
   Restore Modifier:
    DPs:
     active#(f(f(a()))) -> g#(f(a()))
     active#(f(f(a()))) -> f#(g(f(a())))
     active#(f(f(a()))) -> c#(f(g(f(a()))))
     active#(f(f(a()))) -> mark#(c(f(g(f(a())))))
     mark#(f(X)) -> mark#(X)
     mark#(f(X)) -> f#(mark(X))
     mark#(f(X)) -> active#(f(mark(X)))
     mark#(a()) -> active#(a())
     mark#(c(X)) -> active#(c(X))
     mark#(g(X)) -> mark#(X)
     mark#(g(X)) -> g#(mark(X))
     mark#(g(X)) -> active#(g(mark(X)))
     f#(mark(X)) -> f#(X)
     f#(active(X)) -> f#(X)
     c#(mark(X)) -> c#(X)
     c#(active(X)) -> c#(X)
     g#(mark(X)) -> g#(X)
     g#(active(X)) -> g#(X)
    TRS:
     active(f(f(a()))) -> mark(c(f(g(f(a())))))
     mark(f(X)) -> active(f(mark(X)))
     mark(a()) -> active(a())
     mark(c(X)) -> active(c(X))
     mark(g(X)) -> active(g(mark(X)))
     f(mark(X)) -> f(X)
     f(active(X)) -> f(X)
     c(mark(X)) -> c(X)
     c(active(X)) -> c(X)
     g(mark(X)) -> g(X)
     g(active(X)) -> g(X)
    SCC Processor:
     #sccs: 4
     #rules: 8
     #arcs: 37/324
     DPs:
      c#(mark(X)) -> c#(X)
      c#(active(X)) -> c#(X)
     TRS:
      active(f(f(a()))) -> mark(c(f(g(f(a())))))
      mark(f(X)) -> active(f(mark(X)))
      mark(a()) -> active(a())
      mark(c(X)) -> active(c(X))
      mark(g(X)) -> active(g(mark(X)))
      f(mark(X)) -> f(X)
      f(active(X)) -> f(X)
      c(mark(X)) -> c(X)
      c(active(X)) -> c(X)
      g(mark(X)) -> g(X)
      g(active(X)) -> g(X)
     Open
     
     DPs:
      mark#(g(X)) -> mark#(X)
      mark#(f(X)) -> mark#(X)
     TRS:
      active(f(f(a()))) -> mark(c(f(g(f(a())))))
      mark(f(X)) -> active(f(mark(X)))
      mark(a()) -> active(a())
      mark(c(X)) -> active(c(X))
      mark(g(X)) -> active(g(mark(X)))
      f(mark(X)) -> f(X)
      f(active(X)) -> f(X)
      c(mark(X)) -> c(X)
      c(active(X)) -> c(X)
      g(mark(X)) -> g(X)
      g(active(X)) -> g(X)
     Open
     
     DPs:
      f#(active(X)) -> f#(X)
      f#(mark(X)) -> f#(X)
     TRS:
      active(f(f(a()))) -> mark(c(f(g(f(a())))))
      mark(f(X)) -> active(f(mark(X)))
      mark(a()) -> active(a())
      mark(c(X)) -> active(c(X))
      mark(g(X)) -> active(g(mark(X)))
      f(mark(X)) -> f(X)
      f(active(X)) -> f(X)
      c(mark(X)) -> c(X)
      c(active(X)) -> c(X)
      g(mark(X)) -> g(X)
      g(active(X)) -> g(X)
     Open
     
     DPs:
      g#(active(X)) -> g#(X)
      g#(mark(X)) -> g#(X)
     TRS:
      active(f(f(a()))) -> mark(c(f(g(f(a())))))
      mark(f(X)) -> active(f(mark(X)))
      mark(a()) -> active(a())
      mark(c(X)) -> active(c(X))
      mark(g(X)) -> active(g(mark(X)))
      f(mark(X)) -> f(X)
      f(active(X)) -> f(X)
      c(mark(X)) -> c(X)
      c(active(X)) -> c(X)
      g(mark(X)) -> g(X)
      g(active(X)) -> g(X)
     Open