Ultraweak topology

In functional analysis, a branch of mathematics, the ultraweak topology, also called the weak-* topology, or weak-* operator topology or σ-weak topology, is a topology on B(H), the space of bounded operators on a Hilbert space H. B(H) admits a predual B_*(H), the trace class operators on H. The ultraweak topology is the weak-* topology so induced; in other words, the ultraweak topology is the weakest topology such that predual elements remain continuous on B(H).