Abstract. In this paper a new type of $*$-algebras is introduced and investigated in detail to obtain a new characterization of von Neumann algebras. The main theorem (Theorem 5) supplies a characterization of the $*$-algebras $*$-isomorphic to von Neumann algebras, not assuming any previously given analytic property. This work fits to the bundle of research performed by outstanding mathematicians devoted to similar characterization problems (see [5], [6], [8], [16]).

AMS Subject Classification (1991): 46L05, 46L10

Keyword(s): $C^*$-norm, von Neumann algebra, $GW^*$-algebra, $*$-representation

Received May 15, 2008, and in final form July 26, 2010. (Registered under 75/2010.)