Tag Info

Hot answers tagged

3

If you use the definitions in the Wikipedia article to which you linked, you have $$\begin{align*} \Sigma^+&=\bigcup_{k\ge 1}\Sigma_k\\ &=\bigcup_{k\ge 0}\Sigma_{k+1}\\ &=\bigcup_{k\ge 0}\left(\Sigma_k\Sigma\right)\\ &=\left(\bigcup_{k\ge 0}\Sigma_k\right)\Sigma\\ &=\Sigma^*\Sigma\;. \end{align*}$$



Only top voted, non community-wiki answers of a minimum length are eligible