Definition:Open Subset in Strong Operator Topology

Definition
Let $\struct {X, \norm {\, \cdot \,}_X}$ and $\struct {Y, \norm {\, \cdot \,}_Y}$ be normed vector spaces.

Let $\map {CL} {X, Y}$ be a continuous linear transformation space.

Let $\tau$ be the strong operator topology on $\map {CL} {X, Y}$.

Suppose $U \subseteq \map {CL} {X, Y}$ is an open subset such that:


 * $\forall T \in U : \exists \epsilon \in \R_{>0} : \exists n \in \N : \forall k \in \N : k \le n : \exists x_k \in X : \set {S \in \map {CL} {X, Y} : \forall i \in \N : i \le n : \norm {S x_i - T x_i}_Y < \epsilon } \subseteq U$

Then $U$ is called an open subset in $\tau$.