Testing Math in Markdown

$ \mathcal{A} = \langle \Theta, S, \mathcal{E}, \delta \rangle $

$$ \mathcal{A} = \langle \Theta, S, \mathcal{E}, \delta \rangle $$

\[ \mathcal{A} = \langle \Theta, S, \mathcal{E}, \delta \rangle \]

\( \mathcal{A} = \langle \Theta, S, \mathcal{E}, \delta \rangle \)