Definition:Σ*

From CS2800 wiki
Definition: Σ*
The set [math]\href{/cs2800/wiki/index.php?title=%CE%A3%5E*&action=edit&redlink=1}{Σ^*} [/math] of strings with characters in the alphabet [math]\href{/cs2800/wiki/index.php/%CE%A3}{Σ} [/math] is defined inductively by:


[math]\begin{align*} x &\href{/cs2800/wiki/index.php/%E2%88%88}{∈} \href{/cs2800/wiki/index.php?title=%CE%A3%5E*&action=edit&redlink=1}{Σ^*} \href{/cs2800/wiki/index.php/BNF}{::=} \href{/cs2800/wiki/index.php/%CE%95}{ε} \href{/cs2800/wiki/index.php/%5Cmid}{\mid} \href{/cs2800/wiki/index.php?title=Xa&action=edit&redlink=1}{xa} \\ a &\href{/cs2800/wiki/index.php/%E2%88%88}{∈} Σ \end{align*} [/math]