Joshua Erde, Mihyun Kang, Florian Lehner, Bojan Mohar, Dominik Schmid
{"title":"在随机 k-uniform 超图上抓捕劫匪","authors":"Joshua Erde, Mihyun Kang, Florian Lehner, Bojan Mohar, Dominik Schmid","doi":"10.4153/s0008414x24000270","DOIUrl":null,"url":null,"abstract":"<p>The game of <span>Cops and Robber</span> is usually played on a graph, where a group of cops attempt to catch a robber moving along the edges of the graph. The <span>cop number</span> of a graph is the minimum number of cops required to win the game. An important conjecture in this area, due to Meyniel, states that the cop number of an <span>n</span>-vertex connected graph is <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline1.png\"><span data-mathjax-type=\"texmath\"><span>$O(\\sqrt {n})$</span></span></img></span></span>. In 2016, Prałat and Wormald showed that this conjecture holds with high probability for random graphs above the connectedness threshold. Moreover, Łuczak and Prałat showed that on a <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline2.png\"><span data-mathjax-type=\"texmath\"><span>$\\log $</span></span></img></span></span>-scale the cop number demonstrates a surprising <span>zigzag</span> behavior in dense regimes of the binomial random graph <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline3.png\"><span data-mathjax-type=\"texmath\"><span>$G(n,p)$</span></span></img></span></span>. In this paper, we consider the game of Cops and Robber on a hypergraph, where the players move along hyperedges instead of edges. We show that with high probability the cop number of the <span>k</span>-uniform binomial random hypergraph <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline4.png\"><span data-mathjax-type=\"texmath\"><span>$G^k(n,p)$</span></span></img></span></span> is <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline5.png\"><span data-mathjax-type=\"texmath\"><span>$O\\left (\\sqrt {\\frac {n}{k}}\\, \\log n \\right )$</span></span></img></span></span> for a broad range of parameters <span>p</span> and <span>k</span> and that on a <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline6.png\"><span data-mathjax-type=\"texmath\"><span>$\\log $</span></span></img></span></span>-scale our upper bound on the cop number arises as the minimum of <span>two</span> complementary zigzag curves, as opposed to the case of <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline7.png\"><span data-mathjax-type=\"texmath\"><span>$G(n,p)$</span></span></img></span></span>. Furthermore, we conjecture that the cop number of a connected <span>k</span>-uniform hypergraph on <span>n</span> vertices is <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline8.png\"><span data-mathjax-type=\"texmath\"><span>$O\\left (\\sqrt {\\frac {n}{k}}\\,\\right )$</span></span></img></span></span>.</p>","PeriodicalId":501820,"journal":{"name":"Canadian Journal of Mathematics","volume":"52 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Catching a robber on a random k-uniform hypergraph\",\"authors\":\"Joshua Erde, Mihyun Kang, Florian Lehner, Bojan Mohar, Dominik Schmid\",\"doi\":\"10.4153/s0008414x24000270\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The game of <span>Cops and Robber</span> is usually played on a graph, where a group of cops attempt to catch a robber moving along the edges of the graph. The <span>cop number</span> of a graph is the minimum number of cops required to win the game. An important conjecture in this area, due to Meyniel, states that the cop number of an <span>n</span>-vertex connected graph is <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline1.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$O(\\\\sqrt {n})$</span></span></img></span></span>. In 2016, Prałat and Wormald showed that this conjecture holds with high probability for random graphs above the connectedness threshold. Moreover, Łuczak and Prałat showed that on a <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline2.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$\\\\log $</span></span></img></span></span>-scale the cop number demonstrates a surprising <span>zigzag</span> behavior in dense regimes of the binomial random graph <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline3.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$G(n,p)$</span></span></img></span></span>. In this paper, we consider the game of Cops and Robber on a hypergraph, where the players move along hyperedges instead of edges. We show that with high probability the cop number of the <span>k</span>-uniform binomial random hypergraph <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline4.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$G^k(n,p)$</span></span></img></span></span> is <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline5.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$O\\\\left (\\\\sqrt {\\\\frac {n}{k}}\\\\, \\\\log n \\\\right )$</span></span></img></span></span> for a broad range of parameters <span>p</span> and <span>k</span> and that on a <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline6.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$\\\\log $</span></span></img></span></span>-scale our upper bound on the cop number arises as the minimum of <span>two</span> complementary zigzag curves, as opposed to the case of <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline7.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$G(n,p)$</span></span></img></span></span>. Furthermore, we conjecture that the cop number of a connected <span>k</span>-uniform hypergraph on <span>n</span> vertices is <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240425084516565-0876:S0008414X24000270:S0008414X24000270_inline8.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$O\\\\left (\\\\sqrt {\\\\frac {n}{k}}\\\\,\\\\right )$</span></span></img></span></span>.</p>\",\"PeriodicalId\":501820,\"journal\":{\"name\":\"Canadian Journal of Mathematics\",\"volume\":\"52 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-04-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Canadian Journal of Mathematics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.4153/s0008414x24000270\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Canadian Journal of Mathematics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.4153/s0008414x24000270","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
警察抓强盗 "游戏通常在一个图形上进行,一群警察试图抓住沿图形边缘移动的强盗。图的警察数是赢得游戏所需的最少警察数。该领域的一个重要猜想由 Meyniel 提出,即 n 个顶点相连图的警察数为 $O(\sqrt {n})$。2016 年,Prałat 和 Wormald 证明,对于连通性阈值以上的随机图,这一猜想大概率成立。此外,Łuczak 和 Prałat 还表明,在二项式随机图 $G(n,p)$ 的密集状态下,在 $log $ 的尺度上,cop 数表现出令人惊讶的之字形行为。在本文中,我们考虑的是超图上的 "警察与强盗 "游戏,游戏者沿着超边而不是边移动。我们证明,在广泛的参数 p 和 k 范围内,k-均匀二叉随机超图 $G^k(n,p)$ 的警察数很有可能是 $O\left (\sqrt {\frac {n}{k}}\, \log n \right )$,并且在 $\log $ 尺度上,我们的警察数上限是两条互补之字形曲线的最小值,而不是 $G(n,p)$的情况。此外,我们猜想在 n 个顶点上连接 k 个均匀超图的 cop 数是 $O\left (\sqrt {frac {n}{k}}\,\right )$。
Catching a robber on a random k-uniform hypergraph
The game of Cops and Robber is usually played on a graph, where a group of cops attempt to catch a robber moving along the edges of the graph. The cop number of a graph is the minimum number of cops required to win the game. An important conjecture in this area, due to Meyniel, states that the cop number of an n-vertex connected graph is $O(\sqrt {n})$. In 2016, Prałat and Wormald showed that this conjecture holds with high probability for random graphs above the connectedness threshold. Moreover, Łuczak and Prałat showed that on a $\log $-scale the cop number demonstrates a surprising zigzag behavior in dense regimes of the binomial random graph $G(n,p)$. In this paper, we consider the game of Cops and Robber on a hypergraph, where the players move along hyperedges instead of edges. We show that with high probability the cop number of the k-uniform binomial random hypergraph $G^k(n,p)$ is $O\left (\sqrt {\frac {n}{k}}\, \log n \right )$ for a broad range of parameters p and k and that on a $\log $-scale our upper bound on the cop number arises as the minimum of two complementary zigzag curves, as opposed to the case of $G(n,p)$. Furthermore, we conjecture that the cop number of a connected k-uniform hypergraph on n vertices is $O\left (\sqrt {\frac {n}{k}}\,\right )$.