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arXiv 1809.09595math.PRmath.CO
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DeMarco-Kahn上尾猜想的一个反例

A counterexample to the DeMarco-Kahn Upper Tail Conjecture

Matas Šileikis, Lutz Warnke

摘要:

给定一个固定的图H,在二项随机图G_{n,p}中,H的拷贝数X_H至少是其均值的两倍的概率(指数小)是多少?自20世纪90年代中期以来,这个所谓的臭名昭著的上尾问题一直是集中不平等的一个具有挑战性的测试平台。在2011年,DeMarco和Kahn提出了一个有趣的猜想:当ε>0时,\Pr(X_H \ge(1+ε)\E X_H)的指数衰减率。我们表明,这个上尾猜想是假的,通过展示一个无限的家庭的图违反了约束。

英文摘要:

Given a fixed graph H, what is the (exponentially small) probability that the number X_H of copies of H in the binomial random graph G_{n,p} is at least twice its mean? Studied intensively since the mid 1990s, this so-called infamous upper tail problem remains a challenging testbed for concentration inequalities. In 2011 DeMarco and Kahn formulated an intriguing conjecture about the exponential rate of decay of \Pr(X_H \ge (1+ε) \E X_H) for fixed ε>0. We show that this upper tail conjecture is false, by exhibiting an infinite family of graphs violating the conjectured bound.

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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