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{"title":"关于完全对称等分有向图和一致长环的有向Oberwolfach问题","authors":"Nevena Francetić, Mateja Šajna","doi":"10.1002/jcd.21913","DOIUrl":null,"url":null,"abstract":"<p>We examine the necessary and sufficient conditions for a complete symmetric equipartite digraph <math>\n <semantics>\n <mrow>\n <msubsup>\n <mi>K</mi>\n \n <mrow>\n <mi>n</mi>\n \n <mrow>\n <mo>[</mo>\n \n <mi>m</mi>\n \n <mo>]</mo>\n </mrow>\n </mrow>\n \n <mo>*</mo>\n </msubsup>\n </mrow>\n <annotation> ${K}_{n[m]}^{* }$</annotation>\n </semantics></math> with <math>\n <semantics>\n <mrow>\n <mi>n</mi>\n </mrow>\n <annotation> $n$</annotation>\n </semantics></math> parts of size <math>\n <semantics>\n <mrow>\n <mi>m</mi>\n </mrow>\n <annotation> $m$</annotation>\n </semantics></math> to admit a resolvable decomposition into directed cycles of length <math>\n <semantics>\n <mrow>\n <mi>t</mi>\n </mrow>\n <annotation> $t$</annotation>\n </semantics></math>. We show that the obvious necessary conditions are sufficient for <math>\n <semantics>\n <mrow>\n <mi>m</mi>\n \n <mo>,</mo>\n \n <mi>n</mi>\n \n <mo>,</mo>\n \n <mi>t</mi>\n \n <mo>≥</mo>\n \n <mn>2</mn>\n </mrow>\n <annotation> $m,n,t\\ge 2$</annotation>\n </semantics></math> in each of the following four cases: (i) <math>\n <semantics>\n <mrow>\n <mi>m</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>n</mi>\n \n <mo>−</mo>\n \n <mn>1</mn>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation> $m(n-1)$</annotation>\n </semantics></math> is even; (ii) <math>\n <semantics>\n <mrow>\n <mtext>gcd</mtext>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>m</mi>\n \n <mo>,</mo>\n \n <mi>n</mi>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n \n <mo>∉</mo>\n \n <mrow>\n <mo>{</mo>\n \n <mrow>\n <mn>1</mn>\n \n <mo>,</mo>\n \n <mn>3</mn>\n </mrow>\n \n <mo>}</mo>\n </mrow>\n </mrow>\n <annotation> $\\text{gcd}(m,n)\\notin \\{1,3\\}$</annotation>\n </semantics></math>; (iii) <math>\n <semantics>\n <mrow>\n <mtext>gcd</mtext>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>m</mi>\n \n <mo>,</mo>\n \n <mi>n</mi>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n \n <mo>=</mo>\n \n <mn>1</mn>\n </mrow>\n <annotation> $\\text{gcd}(m,n)=1$</annotation>\n </semantics></math> and <math>\n <semantics>\n <mrow>\n <mn>4</mn>\n \n <mo>∣</mo>\n \n <mi>n</mi>\n </mrow>\n <annotation> $4| n$</annotation>\n </semantics></math> or <math>\n <semantics>\n <mrow>\n <mn>6</mn>\n \n <mo>∣</mo>\n \n <mi>n</mi>\n </mrow>\n <annotation> $6| n$</annotation>\n </semantics></math>; and (iv) <math>\n <semantics>\n <mrow>\n <mtext>gcd</mtext>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>m</mi>\n \n <mo>,</mo>\n \n <mi>n</mi>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n \n <mo>=</mo>\n \n <mn>3</mn>\n </mrow>\n <annotation> $\\text{gcd}(m,n)=3$</annotation>\n </semantics></math>, and if <math>\n <semantics>\n <mrow>\n <mi>n</mi>\n \n <mo>=</mo>\n \n <mn>6</mn>\n </mrow>\n <annotation> $n=6$</annotation>\n </semantics></math>, then <math>\n <semantics>\n <mrow>\n <mi>p</mi>\n \n <mo>∣</mo>\n \n <mi>m</mi>\n </mrow>\n <annotation> $p| m$</annotation>\n </semantics></math> for a prime <math>\n <semantics>\n <mrow>\n <mi>p</mi>\n \n <mo>≤</mo>\n \n <mn>37</mn>\n </mrow>\n <annotation> $p\\le 37$</annotation>\n </semantics></math>.</p>","PeriodicalId":15389,"journal":{"name":"Journal of Combinatorial Designs","volume":"31 11","pages":"604-641"},"PeriodicalIF":0.5000,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcd.21913","citationCount":"0","resultStr":"{\"title\":\"On the directed Oberwolfach problem for complete symmetric equipartite digraphs and uniform-length cycles\",\"authors\":\"Nevena Francetić, Mateja Šajna\",\"doi\":\"10.1002/jcd.21913\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We examine the necessary and sufficient conditions for a complete symmetric equipartite digraph <math>\\n <semantics>\\n <mrow>\\n <msubsup>\\n <mi>K</mi>\\n \\n <mrow>\\n <mi>n</mi>\\n \\n <mrow>\\n <mo>[</mo>\\n \\n <mi>m</mi>\\n \\n <mo>]</mo>\\n </mrow>\\n </mrow>\\n \\n <mo>*</mo>\\n </msubsup>\\n </mrow>\\n <annotation> ${K}_{n[m]}^{* }$</annotation>\\n </semantics></math> with <math>\\n <semantics>\\n <mrow>\\n <mi>n</mi>\\n </mrow>\\n <annotation> $n$</annotation>\\n </semantics></math> parts of size <math>\\n <semantics>\\n <mrow>\\n <mi>m</mi>\\n </mrow>\\n <annotation> $m$</annotation>\\n </semantics></math> to admit a resolvable decomposition into directed cycles of length <math>\\n <semantics>\\n <mrow>\\n <mi>t</mi>\\n </mrow>\\n <annotation> $t$</annotation>\\n </semantics></math>. We show that the obvious necessary conditions are sufficient for <math>\\n <semantics>\\n <mrow>\\n <mi>m</mi>\\n \\n <mo>,</mo>\\n \\n <mi>n</mi>\\n \\n <mo>,</mo>\\n \\n <mi>t</mi>\\n \\n <mo>≥</mo>\\n \\n <mn>2</mn>\\n </mrow>\\n <annotation> $m,n,t\\\\ge 2$</annotation>\\n </semantics></math> in each of the following four cases: (i) <math>\\n <semantics>\\n <mrow>\\n <mi>m</mi>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mrow>\\n <mi>n</mi>\\n \\n <mo>−</mo>\\n \\n <mn>1</mn>\\n </mrow>\\n \\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation> $m(n-1)$</annotation>\\n </semantics></math> is even; (ii) <math>\\n <semantics>\\n <mrow>\\n <mtext>gcd</mtext>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mrow>\\n <mi>m</mi>\\n \\n <mo>,</mo>\\n \\n <mi>n</mi>\\n </mrow>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>∉</mo>\\n \\n <mrow>\\n <mo>{</mo>\\n \\n <mrow>\\n <mn>1</mn>\\n \\n <mo>,</mo>\\n \\n <mn>3</mn>\\n </mrow>\\n \\n <mo>}</mo>\\n </mrow>\\n </mrow>\\n <annotation> $\\\\text{gcd}(m,n)\\\\notin \\\\{1,3\\\\}$</annotation>\\n </semantics></math>; (iii) <math>\\n <semantics>\\n <mrow>\\n <mtext>gcd</mtext>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mrow>\\n <mi>m</mi>\\n \\n <mo>,</mo>\\n \\n <mi>n</mi>\\n </mrow>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>=</mo>\\n \\n <mn>1</mn>\\n </mrow>\\n <annotation> $\\\\text{gcd}(m,n)=1$</annotation>\\n </semantics></math> and <math>\\n <semantics>\\n <mrow>\\n <mn>4</mn>\\n \\n <mo>∣</mo>\\n \\n <mi>n</mi>\\n </mrow>\\n <annotation> $4| n$</annotation>\\n </semantics></math> or <math>\\n <semantics>\\n <mrow>\\n <mn>6</mn>\\n \\n <mo>∣</mo>\\n \\n <mi>n</mi>\\n </mrow>\\n <annotation> $6| n$</annotation>\\n </semantics></math>; and (iv) <math>\\n <semantics>\\n <mrow>\\n <mtext>gcd</mtext>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mrow>\\n <mi>m</mi>\\n \\n <mo>,</mo>\\n \\n <mi>n</mi>\\n </mrow>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>=</mo>\\n \\n <mn>3</mn>\\n </mrow>\\n <annotation> $\\\\text{gcd}(m,n)=3$</annotation>\\n </semantics></math>, and if <math>\\n <semantics>\\n <mrow>\\n <mi>n</mi>\\n \\n <mo>=</mo>\\n \\n <mn>6</mn>\\n </mrow>\\n <annotation> $n=6$</annotation>\\n </semantics></math>, then <math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n \\n <mo>∣</mo>\\n \\n <mi>m</mi>\\n </mrow>\\n <annotation> $p| m$</annotation>\\n </semantics></math> for a prime <math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n \\n <mo>≤</mo>\\n \\n <mn>37</mn>\\n </mrow>\\n <annotation> $p\\\\le 37$</annotation>\\n </semantics></math>.</p>\",\"PeriodicalId\":15389,\"journal\":{\"name\":\"Journal of Combinatorial Designs\",\"volume\":\"31 11\",\"pages\":\"604-641\"},\"PeriodicalIF\":0.5000,\"publicationDate\":\"2023-08-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcd.21913\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Combinatorial Designs\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/jcd.21913\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Combinatorial Designs","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jcd.21913","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
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