Definition: A set S2 is a proper subset of another set S1 if every element in S2 is in S1 and S1 has some elements which are not in S2.
See also subset, superset.
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Entry modified 17 December 2004.
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Cite this as:
Paul E. Black, "proper subset", in Dictionary of Algorithms and Data Structures [online], Vreda Pieterse and Paul E. Black, eds. 17 December 2004. (accessed TODAY) Available from: http://www.nist.gov/dads/HTML/propersubset.html