(VAR fun x xs y )
(RULES 
        app(f,0) -> true
        app(f,1) -> false
        app(f,app(s,x)) -> app(f,x)
        app(app(app(if,true),app(s,x)),app(s,y)) -> app(s,x)
        app(app(app(if,false),app(s,x)),app(s,y)) -> app(s,y)
        app(app(g,x),app(c,y)) -> app(c,app(app(g,x),y))
        app(app(g,x),app(c,y)) -> app(app(g,x),app(app(app(if,app(f,x)),app(c,app(app(g,app(s,x)),y))),app(c,y)))
        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)
        
)