# Definition:Letter T

The letter $\mathsf T$ is the topological subspace of the real number plane $\R^2$ under the Euclidean topology defined as:
$\mathsf T := \paren {\closedint {-1} 1 \times \set 0} \cup \paren {\set 0 \times \closedint 0 1}$
• Results about letter $\mathsf T$ can be found here.