Unordered pair
From Encyclopedia of Mathematics - Reading time: 1 min
2020 Mathematics Subject Classification: Primary: 03E [MSN][ZBL]
doubleton
A set containing two elements, denoted $\{x,y\}$. One has $z \in \{x,y\} \Leftrightarrow z = x \vee z = y$, and so $\{x,y\} = \{y,x\}$. Compare with an ordered pair.
References[edit]
| [1] | P. R. Halmos, Naive Set Theory, Springer (1960) ISBN 0-387-90092-6 |
How to Cite This Entry: Unordered pair (Encyclopedia of Mathematics) | Licensed under CC BY-SA 3.0. Source: https://encyclopediaofmath.org/wiki/Unordered_pair7 views | ↧ Download this article as ZWI file
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