The flower intersection problem for Kirkman triple systems |
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Authors: | Yanxun Chang and Giovanni Lo Faro |
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Institution: | a Department of Mathematics, Northern Jiaotong University, Beijing 100044, People's Republic of China b Department of Mathematics, University of Messina, Contrada Papardo, 31-98166 Sant’ Agata, Messina, Italy |
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Abstract: | The flower at a point x in a Steiner triple system
is the set of all triples containing x. Denote by IR*r] the set of all integers k such that there exists a pair of KTS(2r+1) having k+r triples in common, r of them being the triples of a common flower. In this article we determine the set IR*r] for any positive integer r≡1 (mod 3) (only nine cases are left undecided for r=7,13,16,19), and establish that IR*r]=Jr] for r≡1 (mod 3) and r 22 where Jr]={0,1,…,2r(r?1)/3?6,2r(r?1)/3?4,2r(r?1)/3}. |
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Keywords: | Kirkman triple system Frame Flower intersection |
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