English

Isomorphy up to complementation

Combinatorics 2015-01-22 v1

Abstract

Considering uniform hypergraphs, we prove that for every non-negative integer hh there exist two non-negative integers kk and tt with ktk\leq t such that two hh-uniform hypergraphs H{\mathcal H} and H{\mathcal H}' on the same set VV of vertices, with Vt| V| \geq t, are equal up to complementation whenever H{\mathcal H} and H{\mathcal H}' are kk-{hypomorphic up to complementation}. Let s(h)s(h) be the least integer kk such that the conclusion above holds and let v(h)v(h) be the least tt corresponding to k=s(h)k=s(h). We prove that s(h)=h+2log2hs(h)= h+2^{\lfloor \log_2 h\rfloor} . In the special case h=2h=2^{\ell} or h=2+1h=2^{\ell}+1, we prove that v(h)s(h)+hv(h)\leq s(h)+h. The values s(2)=4s(2)=4 and v(2)=6v(2)=6 were obtained in a previous work.

Keywords

Cite

@article{arxiv.1501.05181,
  title  = {Isomorphy up to complementation},
  author = {Maurice Pouzet and Hamza Si Kaddour},
  journal= {arXiv preprint arXiv:1501.05181},
  year   = {2015}
}

Comments

15 pages

R2 v1 2026-06-22T08:08:30.897Z