Skip to main content

recursively enumerable set

recursively enumerable set A subset A of a set B is said to be recursively enumerable, relative to B, if there is an effective procedure that, given an element b in B, will output “yes” if and only if b is an element of A. If b is not in A then, in general, the procedure will never terminate. This is a weaker notion than that of a recursive set. A set can be recursively enumerable without being recursive. The set A is also said to be semidecidable or semicomputable.

The set of Ada programs that terminates (for a given input) is recursively enumerable (with respect to the class of all Ada programs) but it is not recursive.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"recursively enumerable set." A Dictionary of Computing. . 25 Jun. 2019 <>.

"recursively enumerable set." A Dictionary of Computing. . (June 25, 2019).

"recursively enumerable set." A Dictionary of Computing. . Retrieved June 25, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.