We show that if a Lebesgue-integrable function f : R --> R satisfies t
he functional equation f [x1, x2,...,x(n)] = h(x1 + x2 + ...+ x(n)), t
hen f is a polynomial of degree at most n. This answers a question rai
sed by Bailey [1]. Furthermore, we give two other (but related) charac
terizations of polynomials.