Automorphic forms on O_{s+2,2}(R)^+ and generalized Kac-Moody algebras. 
Proceedings of the International Congress of Mathematicians, Vol. 1, 2 
(Z\"urich, 1994), 744-752, Birkh\"auser, Basel, 1995. 

Richard E. Borcherds 

Department of Mathematics, University of California at Berkeley, 
CA 94720-3840, USA. 

We discuss how modular forms and automorphic forms can be written as 
infinite products, and how some of these infinite products appear in 
the theory of generalized Kac-Moody algebras. This paper is based on 
my talk at the ICM, and is an exposition of [B5].