I noticed in another answer on this forum Note that the languages , {} and * are regular.How do you prove Sigma Star is regular.
How do you prove Sigma Star is regular
formal languages;regular languages
It's easy to design a DFA that accepts $\Sigma^*$. Or, if your definition of regular languages is in terms of regular expressions, then the regular expression $(a_1\mid\dots\mid a_k)^*$ matches $\Sigma^*$, where $\Sigma = \{a_1, \dots, a_k\}$.