In functional analysis and related areas of mathematics, the strong dual space of a topological vector space (TVS) X {\displaystyle X} is the continuous dual space X ′ {\displaystyle X^{\prime }} of X {\displaystyle X} equipped with the strong (dual) topology or the topology of uniform convergence on bounded subsets of X , {\displaystyle X,} where this topology is denoted by b ( X ′ , X ) {\displaystyle b\left(X^{\prime },X\right)} or β ( X ′ , X ) . {\displaystyle \beta \left(X^{\prime },X\right).} The coarsest polar topology is called weak topology. The strong dual space plays such an important role in modern functional analysis, that the continuous dual space is usually assumed to have the strong dual topology unless indicated otherwise. To emphasize that the continuous dual space, X ′ , {\displaystyle X^{\prime },} has the strong dual topology, X b ′ {\displaystyle X_{b}^{\prime }} or X β ′ {\displaystyle X_{\beta }^{\prime }} may be written.