(VAR x y xs f) (RULES app(app(\, x), x) -> e app(app(\, e), x) -> x app(app(\, x), app(app(., x), y)) -> y app(app(\, app(app(/, x), y)), x) -> y app(app(/, x), x) -> e app(app(/, x), e) -> x app(app(/, app(app(., y), x)), x) -> y app(app(/, x), app(app(\, y), x)) -> y app(app(., e), x) -> x app(app(., x), e) -> x app(app(., x), app(app(\, x), y)) -> y app(app(., app(app(/, y), x)), x) -> y app(app(map,f),nil) -> nil app(app(map,f),app(app(cons,x),xs)) -> app(app(cons,app(f,x)),app(app(map,f),xs)) app(app(filter,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(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) )