Problem:
 h(h(a(),a()),a()) -> f(a())
 c() -> h(a(),a())
 c() -> c()
 f(c()) -> a()

Proof:
 Uncurry Processor:
  f4(f4(h(),f4(f4(h(),a()),a())),a()) -> f4(f(),a())
  c() -> f4(f4(h(),a()),a())
  c() -> c()
  f4(f(),c()) -> a()
  Ground Confluence Processor:
   not UN by decision procedure.