Enumerator (computer science)


An enumerator is a Turing machine that lists, possibly with repetitions, elements of some set S, which it is said to enumerate. A set enumerated by some enumerator is said to be recursively enumerable.

Formal definition

An enumerator is usually represented as a 2-tape Turing machine. One working tape, and one print tape. It can be defined by a 7-tuple, following the notation of a Turing machine:
where