Holomorphic functions of exponential type on connected complex Lie groups

Abstract

Holomorphic functions of exponential type on a complex Lie group $G$ (introduced by Akbarov) form a locally convex algebra, which is denoted by $\cO_{exp}(G)$. Our aim is to describe the structure of $\cO_{exp}(G)$ in the case when $G$ is connected. The following topics are auxiliary for the claimed purpose but of independent interest: (1) a characterization of linear complex Lie group (a~result similar to that of Luminet and Valette for real Lie groups); (2) properties of the exponential radical when $G$ is linear; (3) an asymptotic decomposition of a word length function into a sum of three summands (again for linear groups). The main result presents $\cO_{exp}(G)$ as a complete projective tensor of three factors, corresponding to the length function decomposition. As an application, it is shown that if $G$ is linear then the Arens-Michael envelope of $\cO_{exp}(G)$ is just the algebra of all holomorphic functions.