(VAR f x xs y )
(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)
        
)