Difference between revisions of "Countable set"
From Encyclopedia of Mathematics
(Comment: In some texts, this definition is called a "countably infinite" set) |
(→Comments: or "denumerable") |
||
| Line 2: | Line 2: | ||
====Comments==== | ====Comments==== | ||
| − | In some texts, this definition is that a "countably infinite" set, and a "countable" set refers to one which is finite or countably infinite: that is, a set of the same cardinality as some subset of the natural numbers. | + | In some texts, this definition is that of a "countably infinite" or "denumerable" set, and a "countable" set refers to one which is finite or countably infinite: that is, a set of the same cardinality as some subset of the natural numbers. |
Revision as of 20:35, 12 October 2014
A set of the same cardinality as the set of natural numbers. For example, the set of rational numbers or the set of algebraic numbers.
Comments
In some texts, this definition is that of a "countably infinite" or "denumerable" set, and a "countable" set refers to one which is finite or countably infinite: that is, a set of the same cardinality as some subset of the natural numbers.
How to Cite This Entry:
Countable set. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Countable_set&oldid=33594
Countable set. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Countable_set&oldid=33594
This article was adapted from an original article by M.I. Voitsekhovskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article