Yes.

It is sometimes awkward to draw an automaton.
A drawing takes up space and is not easily used as program input.
A regular language can be described in a
math-like manner using a
* regular expression*.
For example,
the following regular expression describes the same language
as the automaton at right.

```
````(xy)*xz|(ab*c)`

Don't worry (for now) about how the regular expression works. Regular expressions are discussed in another chapter.

A regular language can be described by either a finite automaton or by a regular expression. A laguage that can be described by one can also be be described by the other. To write a program that accepts a regular language it is easier to think in terms of a finite automaton.

Warning: in practice, the idea of regular expressions
has been extended to include features that
do not correspond to a finite automaton.
The languages these extended regular expressions
recognize are not always regular languages.
Such an extended regular expressions is sometimes
called a **regex**.

However, for the first sections of these notes a "regular expression" will correspond to a regular language, and both will correspond to a finite automaton.

Do finite automata deal only with strings of characters?