apply(sign,x) == x

[Jacques Gélinas <jacquesg00@hotmail.com>]

apply(f, A): If A  is  a  polynomial or power series,  apply f on all coefficients. 

Of course, I would expect sign not to return a polynomial, but -1, 0, or 1 as in

apply(sign,Vec(x)) == [1,0]

Jacques Gélinas