English

Classification of small $(0,1)$ matrices

Combinatorics 2007-05-23 v1

Abstract

Denote by AnA_n the set of square (0,1)(0,1) matrices of order nn. The set AnA_n, n8n\le8, is partitioned into row/column permutation equivalence classes enabling derivation of various facts by simple counting. For example, the number of regular (0,1)(0,1) matrices of order 8 is 10160459763342013440. Let DnD_n, SnS_n denote the set of absolute determinant values and Smith normal forms of matrices from AnA_n. Denote by ana_n the smallest integer not in DnD_n. The sets D9\mathcal{D}_9 and S9\mathcal{S}_9 are obtained; especially, a9=103a_9=103. The lower bounds for ana_n, 10n1910\le n\le 19, (exceeding the known lower bound an2fn1a_n\ge 2f_{n-1}, where fnf_n is nnth Fibonacci number) are obtained. Row/permutation equivalence classes of AnA_n correspond to bipartite graphs with nn black and nn white vertices, and so the other applications of the classification are possible.

Keywords

Cite

@article{arxiv.math/0511636,
  title  = {Classification of small $(0,1)$ matrices},
  author = {Miodrag Živković},
  journal= {arXiv preprint arXiv:math/0511636},
  year   = {2007}
}

Comments

45 pages. submitted to LAA