Title: Factorization of bivariate and multivariate trigonometric polynomials
<br><br>
Abstract: An important problem in mathematics  is how to write a positive
polynomial as a sum of squares of polynomials or rational functions. The simplest case is the Fejer-Riesz Lemma which shows how to write a trigonometric polynomial of a certain degree in one variable as the magnitude square of an algebraic polynomial of the same degree. I will review some applications of this result as well as discuss some recent extensions.