# Alphabet

From Encyclopedia of Mathematics

A list (finite set) of letters (cf. Letter). An alphabet usually contains the letters which are required to develop a certain system of symbols or, as is sometimes said, a language. For two alphabets and , their union , their intersection , their difference , as well as the inclusion relation are defined in the obvious manner. For convenience, the concept of an empty alphabet, i.e. an alphabet without any letters, may also be considered.

**How to Cite This Entry:**

Alphabet.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Alphabet&oldid=14016

This article was adapted from an original article by N.M. Nagornyi (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article