Polynomials over ordered fields

In this paper we determine which polynomials over ordered fields have multiples with nonnegative coefficients and also which polynomials can be written as quotients of two polynomials with nonnegative coefficients. This problem is related to a result given by Pólya in [G.H. Hardy, J.E. Littlewood, G. Pólya, Inequalities, Cambridge University Press, Cambridge, England, 1952] (as a companion of Artin’s theorem) that asserts that if image is a form (i.e., a homogeneous polynomial) s.t. image with ∑xj>0, then F=G/H, where G,H are forms with all coefficients positive (i.e., every monomial of degree degG or degH appears in G or H, resp., with a coefficient that is strictly positive). In Pólya’s proof H is chosen to be H=(X1+cdots, three dots, centered+Xn)m for some m. At the end we give some applications, including a generalization of Pólya’s result to arbitrary ordered fields.