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The design spectrum of the Shrikhande graph

Combinatorics 2025-08-05 v2

Abstract

The design spectrum of a simple graph GG is the set of positive integers nn such that there exists an edgewise decomposition of the complete graph KnK_n into n(n1)/(2E(G))n(n - 1)/(2 |E(G)|) copies of GG. The purpose of this short paper is to prove that the Shrikhande graph and the line graph of K4,4K_{4,4} have the design spectrum {96t+1:t=1,2,}\{96t + 1: t = 1, 2, \dots\}.

Keywords

Cite

@article{arxiv.2505.00859,
  title  = {The design spectrum of the Shrikhande graph},
  author = {Anthony D. Forbes and Carrie G. Rutherford},
  journal= {arXiv preprint arXiv:2505.00859},
  year   = {2025}
}

Comments

5 pages. Section 3 updated; Theorem 3.2 added. The paper is under review. arXiv admin note: text overlap with arXiv:2401.02846