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