(definition)
Definition: A binary relation R for which a R b implies b R a.
See also reflexive, transitive, antisymmetric.
Note: The relation "not equal to" is symmetric: if a ≠ b, then b ≠ a. However, "loves" is not symmetric since love might not be reciprocated. The relation "is married to" is symmetric, but not antisymmetric: if Paul is married to Marlena, then Marlena is married to Paul (symmetric), but that does not mean that Paul and Marlena are the same person.
Author: PEB
If you have suggestions, corrections, or comments, please get in touch with Paul E. Black.
Entry modified Fri Dec 17 12:08:07 2004.
HTML page formatted Wed Oct 26 09:48:15 2005.
Cite this as:
Paul E. Black, "symmetric", from
Dictionary of Algorithms and Data
Structures, Paul E. Black, ed.,
NIST.
http://www.nist.gov/dads/HTML/symmetric.html
