DIVISION ALGEBRAS THAT RAMIFY ONLY ON THE ZEROS OF AN ELEMENTARY SYMMETRIC POLYNOMIAL

DIVISION ALGEBRAS THAT RAMIFY ONLY ON THE ZEROS OF AN ELEMENTARY SYMMETRIC POLYNOMIAL

Let k be an algebraically closed field of characteristic zero. The elementary symmetric polynomial of degree n − 1 in n variables is a homogeneous polynomial, hence defines both an affine variety in An k which we denote by Cn−1 and a projective variety in Pn−1k denoted Vn−1. We describe, up to Brauer equivalence, the central division algebras over the rational function field of An which ramify only on Cn−1 as well as the central division algebras over the rational function field of Pn−1 that ramify only on Vn−1. The Brauer group of the cubic surface V3 in P3 is computed and is shown to consist solely of Azumaya algebras that are locally trivial in the Zariski topology.