{"title":"\"在有路径的六个顶点的轮子连接处的交叉数上\"","authors":"\"ŠTEFAN ŠTEFAN\" Berežný, M. Staš","doi":"10.37193/cjm.2022.02.06","DOIUrl":null,"url":null,"abstract":"The crossing number $\\mathrm{cr}(G)$ of a graph $G$ is the minimum number of edge crossings over all drawings of $G$ in the plane. The main aim of the paper is to give the crossing number of join product $W_5+P_n$ for the wheel $W_5$ on six vertices, where $P_n$ is the path on $n$ vertices. Sta\\v s and Valiska conjectured that the crossing number of $W_m+P_n$ is equal to $Z(m+1)Z(n) + (Z(m)-1) \\big \\lfloor \\frac{n}{2} \\big \\rfloor + n +1$, for all $m\\geq 3$, $n\\geq 2$, where Zarankiewicz's number is defined as $Z(n)=\\big \\lfloor \\frac{n}{2} \\big \\rfloor \\big \\lfloor \\frac{n-1}{2} \\big \\rfloor $ for $n\\geq 1$. Recently, this conjecture was proved for $W_3+P_n$ by Kle\\v s\\v c and Schr\\\"otter, and for $W_4+P_n$ by Sta\\v s and Valiska. We establish the validity of this conjecture for $W_5+P_n$. The conjecture also holds due to some isomorphisms for $W_m+P_2$, $W_m+P_3$ by Kle\\v s\\v c, and for $W_m+P_4$ by Sta\\v s for all $m\\geq 3$.","PeriodicalId":50711,"journal":{"name":"Carpathian Journal of Mathematics","volume":null,"pages":null},"PeriodicalIF":1.4000,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"\\\"On the crossing number of the join of the wheel on six vertices with a path\\\"\",\"authors\":\"\\\"ŠTEFAN ŠTEFAN\\\" Berežný, M. Staš\",\"doi\":\"10.37193/cjm.2022.02.06\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The crossing number $\\\\mathrm{cr}(G)$ of a graph $G$ is the minimum number of edge crossings over all drawings of $G$ in the plane. The main aim of the paper is to give the crossing number of join product $W_5+P_n$ for the wheel $W_5$ on six vertices, where $P_n$ is the path on $n$ vertices. Sta\\\\v s and Valiska conjectured that the crossing number of $W_m+P_n$ is equal to $Z(m+1)Z(n) + (Z(m)-1) \\\\big \\\\lfloor \\\\frac{n}{2} \\\\big \\\\rfloor + n +1$, for all $m\\\\geq 3$, $n\\\\geq 2$, where Zarankiewicz's number is defined as $Z(n)=\\\\big \\\\lfloor \\\\frac{n}{2} \\\\big \\\\rfloor \\\\big \\\\lfloor \\\\frac{n-1}{2} \\\\big \\\\rfloor $ for $n\\\\geq 1$. Recently, this conjecture was proved for $W_3+P_n$ by Kle\\\\v s\\\\v c and Schr\\\\\\\"otter, and for $W_4+P_n$ by Sta\\\\v s and Valiska. We establish the validity of this conjecture for $W_5+P_n$. The conjecture also holds due to some isomorphisms for $W_m+P_2$, $W_m+P_3$ by Kle\\\\v s\\\\v c, and for $W_m+P_4$ by Sta\\\\v s for all $m\\\\geq 3$.\",\"PeriodicalId\":50711,\"journal\":{\"name\":\"Carpathian Journal of Mathematics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.4000,\"publicationDate\":\"2022-02-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Carpathian Journal of Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.37193/cjm.2022.02.06\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carpathian Journal of Mathematics","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.37193/cjm.2022.02.06","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
"On the crossing number of the join of the wheel on six vertices with a path"
The crossing number $\mathrm{cr}(G)$ of a graph $G$ is the minimum number of edge crossings over all drawings of $G$ in the plane. The main aim of the paper is to give the crossing number of join product $W_5+P_n$ for the wheel $W_5$ on six vertices, where $P_n$ is the path on $n$ vertices. Sta\v s and Valiska conjectured that the crossing number of $W_m+P_n$ is equal to $Z(m+1)Z(n) + (Z(m)-1) \big \lfloor \frac{n}{2} \big \rfloor + n +1$, for all $m\geq 3$, $n\geq 2$, where Zarankiewicz's number is defined as $Z(n)=\big \lfloor \frac{n}{2} \big \rfloor \big \lfloor \frac{n-1}{2} \big \rfloor $ for $n\geq 1$. Recently, this conjecture was proved for $W_3+P_n$ by Kle\v s\v c and Schr\"otter, and for $W_4+P_n$ by Sta\v s and Valiska. We establish the validity of this conjecture for $W_5+P_n$. The conjecture also holds due to some isomorphisms for $W_m+P_2$, $W_m+P_3$ by Kle\v s\v c, and for $W_m+P_4$ by Sta\v s for all $m\geq 3$.
期刊介绍:
Carpathian Journal of Mathematics publishes high quality original research papers and survey articles in all areas of pure and applied mathematics. It will also occasionally publish, as special issues, proceedings of international conferences, generally (co)-organized by the Department of Mathematics and Computer Science, North University Center at Baia Mare. There is no fee for the published papers but the journal offers an Open Access Option to interested contributors.