Enumerating Steiner triple systems

被引:2
|
作者
Heinlein, Daniel [1 ,2 ]
Ostergard, Patric R. J. [1 ]
机构
[1] Aalto Univ, Sch Elect Engn, Dept Informat & Commun Engn, Aalto, Finland
[2] Aalto Univ, Sch Elect Engn, Dept Informat & Commun Engn, POB 15400, Aalto 00076, Finland
基金
芬兰科学院;
关键词
classification; counting; regular graph; Steiner triple system; FAST GENERATION; LATIN SQUARES; ORDER; 21; GRAPHS;
D O I
10.1002/jcd.21906
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Steiner triple systems (STSs) have been classified up to order 19. Earlier estimations of the number of isomorphism classes of STSs of order 21, the smallest open case, are discouraging as for classification, so it is natural to focus on the easier problem of merely counting the isomorphism classes. Computational approaches for counting STSs are here considered and lead to an algorithm that is used to obtain the number of isomorphism classes for order 21: 14,796,207,517,873,771.
引用
收藏
页码:479 / 495
页数:17
相关论文
共 50 条
  • [41] FROM STEINER TRIPLE SYSTEMS TO 3-SUN SYSTEMS
    Fu, Chin-Mei
    Jhuang, Nan-Hua
    Lin, Yuan-Lung
    Sung, Hsiao-Ming
    TAIWANESE JOURNAL OF MATHEMATICS, 2012, 16 (02): : 531 - 543
  • [43] Steiner triple systems and spreading sets in projective spaces
    Nagy, Zoltan Lorant
    Szemeredi, Levente
    JOURNAL OF COMBINATORIAL DESIGNS, 2022, 30 (08) : 549 - 560
  • [44] On the upper embedding of Steiner triple systems and Latin squares
    Griggs, Terry S.
    McCourt, Thomas A.
    Siran, Jozef
    ARS MATHEMATICA CONTEMPORANEA, 2020, 18 (01) : 127 - 135
  • [45] On the number of small Steiner triple systems with Veblen points
    Filippone, Giuseppe
    Galici, Mario
    DISCRETE MATHEMATICS, 2025, 348 (01)
  • [46] On the maximum double independence number of Steiner triple systems
    Lusi, Dylan
    Colbourn, Charles J.
    JOURNAL OF COMBINATORIAL DESIGNS, 2020, 28 (10) : 713 - 723
  • [47] Uniquely 3-colourable Steiner triple systems
    Forbes, AD
    JOURNAL OF COMBINATORIAL THEORY SERIES A, 2003, 101 (01) : 49 - 68
  • [48] EMBEDDING PARTIAL STEINER TRIPLE SYSTEMS WITH FEW TRIPLES
    Horsley, Daniel
    SIAM JOURNAL ON DISCRETE MATHEMATICS, 2014, 28 (03) : 1199 - 1213
  • [49] The configuration polytope of a""-line configurations in Steiner triple systems
    Colbourn, Charles J.
    MATHEMATICA SLOVACA, 2009, 59 (01) : 77 - 108
  • [50] λ-fold indecomposable large sets of Steiner triple systems
    Ji LiJun
    Tian ZiHong
    Kang QingDe
    SCIENCE CHINA-MATHEMATICS, 2010, 53 (11) : 2877 - 2888