Regular Language

A regular language is a set of strings over some alphabet $\sum$ that can be recognized by a Finite Automaton.

Formally, a language $L\subseteq \sum \ast$ is regular if there exists a deterministic or nondeterministic finite automaton that accepts exactly the strings in $L$.

Equivalent characterizations:

• $L$ can be described by a Regular Expression.

The set of all regular languages over $\sum$ is denoted by $\mathcal{R}\mathcal{EG}$.