(VAR fun x xs y z )
(RULES 
        app(f,app(app(cons,nil),y)) -> y
        app(f,app(app(cons,app(f,app(app(cons,nil),y))),z)) -> app(app(app(copy,n),y),z)
        app(app(app(copy,0),y),z) -> app(f,z)
        app(app(app(copy,app(s,x)),y),z) -> app(app(app(copy,x),y),app(app(cons,app(f,y)),z))
        app(app(map,fun),nil) -> nil
        app(app(map,fun),app(app(cons,x),xs)) -> app(app(cons,app(fun,x)),app(app(map,fun),xs))
        app(app(filter,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(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)
        
)