Journal of Integer Sequences, Vol. 21 (2018), Article 18.1.7

Generation of Union-Closed Sets and Moore Families


Gunnar Brinkmann and Robin Deklerck
Applied Mathematics, Computer Science and Statistics
Ghent University
Krijgslaan 281 S9
B9000 Ghent
Belgium

Abstract:

We describe an algorithm to constructively enumerate non-isomorphic union-closed sets and Moore sets. We confirm the number of isomorphism classes of union-closed sets and Moore sets on n ≤ 6 elements presented by other authors, and give the number of isomorphism classes of union-closed sets and Moore sets on 7 elements. Due to the enormous growth of the number of isomorphism classes, it seems unlikely that constructive enumeration for 8 or more elements will be possible in the foreseeable future.


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(Concerned with sequences A102894 A102896 A108798 A193674 A299116.)


Received November 20 2017; revised version received February 5 2018. Published in Journal of Integer Sequences, February 8 2018.


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