DEFINITION OF CHERN-SIMONS TERMS IN THERMAL QED(3) REVISITED

We present two compact derivations of the correct definition of the Ch ern-Simons term in the topologically non trivial context of thermal QE D(3). One is based on a transgression descent from a D = 4 background connection, the other on embedding the abelian model in SU(2). The res ults agree with earlier cohomology conclusions and can be also used to justify a recent simple heuristic approach. The correction to the nai ve Chern-Simons term, and its behavior under large gauge transformatio ns are displayed.