English

On solving isomorphism problems about 2-designs using block intersection numbers

Combinatorics 2019-11-21 v2

Abstract

In this paper, we give a partial solution to a new isomorphism problem about 22-(v,k,k1)(v,k,k-1) designs from disjoint difference families in finite fields and Galois rings. Our results are obtained by carefully calculating and bounding some block intersection numbers, and we give insight on the limitations of this technique. Moreover, we present results on cyclotomic numbers and on the structure of Galois rings of characteristic p2p^2.

Keywords

Cite

@article{arxiv.1907.05848,
  title  = {On solving isomorphism problems about 2-designs using block intersection numbers},
  author = {Christian Kaspers and Alexander Pott},
  journal= {arXiv preprint arXiv:1907.05848},
  year   = {2019}
}

Comments

20 pages. v2: Added additional results. Fixed a mistake in the main theorem. arXiv admin note: text overlap with arXiv:1807.02055

R2 v1 2026-06-23T10:19:48.444Z