MAYBE
MAYBE
TRS:
 {
  app(app(app(fold(), f), app(app(cons(), h), t)), x) ->
  app(app(app(fold(), f), t), app(app(f, x), h)),
                   app(app(app(fold(), f), nil()), x) -> x,
                 app(app(app(fold(), mul()), l), 1()) -> app(prod(), l),
                                        app(sum(), l) ->
  app(app(app(fold(), add()), l), 0())
 }
 DUP: We consider a duplicating system.
  Trs:
   {
    app(app(app(fold(), f), app(app(cons(), h), t)), x) ->
    app(app(app(fold(), f), t), app(app(f, x), h)),
                     app(app(app(fold(), f), nil()), x) -> x,
                   app(app(app(fold(), mul()), l), 1()) -> app(prod(), l),
                                          app(sum(), l) ->
    app(app(app(fold(), add()), l), 0())
   }
  Fail