Properties of Steiner triple systems of order 21
Combinatorics
2024-01-25 v1
Abstract
Properties of the 62,336,617 Steiner triple systems of order 21 with a non-trivial automorphism group are examined. In particular, there are 28 which have no parallel class, six that are 4-chromatic, five that are 3-balanced, 20 that avoid the mitre, 21 that avoid the crown, one that avoids the hexagon and two that avoid the prism. All systems contain the grid. None have a block intersection graph that is 3-existentially closed.
Keywords
Cite
@article{arxiv.2401.13356,
title = {Properties of Steiner triple systems of order 21},
author = {Grahame Erskine and Terry S. Griggs},
journal= {arXiv preprint arXiv:2401.13356},
year = {2024}
}
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12 pages