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arXiv 2012.06160math.CO
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强步正则图、三和集及其编码

On strongly walk regular graphs, triple sum sets and their codes

Michael Kiermaier, Sascha Kurz, Patrick Solé, Michael Stoll, Alfred Wassermann

AI总结:

本文研究强步正则图($s$-SWRGs)及其关联的射影三重权编码,分类了中等码长二元/三元编码的可行参数,证明$s=5,7$时对应平面代数曲线仅平凡解,推测该结论对所有奇数$s≥9$成立。

摘要:

强步正则图(SWRGs 或 $s$-SWRGs)是强正则图(SRGs)的自然推广,其中长度为2的路径被替换为长度为$s$的路径。它们可以构造为权重满足某一特定方程的射影三重权编码对偶的陪集图。我们对中等码长下二元和三元情形中这类编码的可行参数进行了分类。对于二元情形,我们研究了这类编码权重的可除性,并证明了若干一般性结果。已知$s$-SWRG 至多有4个不同的特征值$k > θ_1 > θ_2 > θ_3$,且三元组$(θ_1, θ_2, θ_3)$满足某一特定的$s-2$次齐次多项式方程(Van Dam, Omidi, 2013)。该方程定义了一条平面代数曲线;我们运用算法算术几何的方法证明,当$s=5$和$s=7$时,仅存在平凡解,并推测对于所有(奇)$s \ge 9$,该结论依然成立。

英文摘要:

Strongly walk regular graphs (SWRGs or $s$-SWRGs) form a natural generalization of strongly regular graphs (SRGs) where paths of length~2 are replaced by paths of length~$s$. They can be constructed as coset graphs of the duals of projective three-weight codes whose weights satisfy a certain equation. We provide classifications of the feasible parameters of these codes in the binary and ternary case for medium size code lengths. For the binary case, the divisibility of the weights of these codes is investigated and several general results are shown. It is known that an $s$-SWRG has at most 4 distinct eigenvalues $k > θ_1 > θ_2 > θ_3$, and that the triple $(θ_1, θ_2, θ_3)$ satisfies a certain homogeneous polynomial equation of degree $s - 2$ (Van Dam, Omidi, 2013). This equation defines a plane algebraic curve; we use methods from algorithmic arithmetic geometry to show that for $s = 5$ and $s = 7$, there are only the obvious solutions, and we conjecture this to remain true for all (odd) $s \ge 9$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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