Kleene closure

Meanings

1. The set of all strings of finite length made up of elements of a given set. (Then the Kleene closure is said to be of that given set. For a given set S, its Kleene closure may be denoted as S^*. The Kleene closure includes a string of zero length. Strings are equivalent to ordered tuples but written without the parentheses and commas.)

Etymology

Named in honor of Stephen Cole Kleene (1909–1994), an American mathematician. The “closure” part comes from the fact that a Kleene closure is closed with respect to concatenation; cf. free monoid.