MAYBE
MAYBE
TRS:
 {
   app(app(app(app(filter2(), true()), fun), x), xs) ->
  app(app(cons(), x), app(app(filter(), fun), xs)),
  app(app(app(app(filter2(), false()), fun), x), xs) ->
  app(app(filter(), fun), xs),
               app(app(app(f(), x), y), app(s(), z)) ->
  app(s(), app(app(app(f(), 0()), 1()), z)),
                     app(app(app(f(), 0()), 1()), x) ->
  app(app(app(f(), app(s(), x)), x), x),
       app(app(map(), fun), app(app(cons(), x), xs)) ->
  app(app(cons(), app(fun, x)), app(app(map(), fun), xs)),
                         app(app(map(), fun), nil()) -> nil(),
    app(app(filter(), fun), app(app(cons(), x), xs)) ->
  app(app(app(app(filter2(), app(fun, x)), fun), x), xs),
                      app(app(filter(), fun), nil()) -> nil()
 }
 DUP: We consider a duplicating system.
  Trs:
   {
     app(app(app(app(filter2(), true()), fun), x), xs) ->
    app(app(cons(), x), app(app(filter(), fun), xs)),
    app(app(app(app(filter2(), false()), fun), x), xs) ->
    app(app(filter(), fun), xs),
                 app(app(app(f(), x), y), app(s(), z)) ->
    app(s(), app(app(app(f(), 0()), 1()), z)),
                       app(app(app(f(), 0()), 1()), x) ->
    app(app(app(f(), app(s(), x)), x), x),
         app(app(map(), fun), app(app(cons(), x), xs)) ->
    app(app(cons(), app(fun, x)), app(app(map(), fun), xs)),
                           app(app(map(), fun), nil()) -> nil(),
      app(app(filter(), fun), app(app(cons(), x), xs)) ->
    app(app(app(app(filter2(), app(fun, x)), fun), x), xs),
                        app(app(filter(), fun), nil()) -> nil()
   }
  Fail