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A linear extension of a partially ordered set is a permutation
of the elements , , ... of such that implies . For example,
the linear extensions of the partially
ordered set are 1234, 1324, 1342, 3124,
3142, and 3412, all of which have 1 before 2 and 3 before 4.
Brightwell, G. and Winkler, P. "Counting Linear Extensions." Order 8,
225-242, 1991.
Brualdi, R. A. Introductory Combinatorics, 4th ed. New York: Elsevier,
1997.
Bubley, R. and Dyer, M. "Faster Random Generation of Linear Extensions." In Proc. Ninth Annual ACM-SIAM Symposium on Discrete Algorithms, San Francisco,
Calif., pp. 350-354, 1998.
Preusse, G. and Ruskey, F. "Generating Linear Extensions Fast." SIAM
J. Comput. 23, 373-386, 1994.
Varol, Y. and Rotem, D. "An Algorithm to Generate All Topological Sorting Arrangements."
Comput. J. 24, 83-84, 1981.
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