{"title":"On characterizing the extreme points of the generalized transitive tournament polytope","authors":"Konstantinos Papalamprou","doi":"10.1016/j.endm.2018.06.047","DOIUrl":null,"url":null,"abstract":"<div><p>A non-negative <span><math><mi>n</mi><mo>×</mo><mi>n</mi></math></span> matrix [<span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi><mi>j</mi></mrow></msub></math></span>] is called generalized tournament, denoted GTT(n), if: <span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi><mi>i</mi></mrow></msub><mo>=</mo><mn>0</mn></math></span> (for all i), <span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>+</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>j</mi><mi>i</mi></mrow></msub><mo>=</mo><mn>1</mn></math></span> (for all(i,j) with <span><math><mi>i</mi><mo>≠</mo><mi>j</mi></math></span>) and <span><math><mn>1</mn><mo>≤</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo>+</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>j</mi><mi>k</mi></mrow></msub><mo>+</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>k</mi><mi>i</mi></mrow></msub><mo>≤</mo><mn>2</mn></math></span> (for all (i,j,k) with <span><math><mi>i</mi><mo>,</mo><mi>j</mi><mo>,</mo><mi>k</mi></math></span> pairwise distinct). In [9], using hypergraphs associated with GTT matrices, it has been shown that for <span><math><mi>n</mi><mo>≤</mo><mn>6</mn></math></span> all the vertices of the GTT(n) polytope are half-integral. In this work, we show that these matrices belong to the class of 2-regular matrices and highlight the related optimization implications. Finally, based on our approach and known partial results, conjectures on characterizing the extreme points of the GTT(n) polytope for <span><math><mi>n</mi><mo>≥</mo><mn>7</mn></math></span> are provided.</p></div>","PeriodicalId":35408,"journal":{"name":"Electronic Notes in Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.endm.2018.06.047","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electronic Notes in Discrete Mathematics","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1571065318301380","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Mathematics","Score":null,"Total":0}
引用次数: 0
Abstract
A non-negative matrix [] is called generalized tournament, denoted GTT(n), if: (for all i), (for all(i,j) with ) and (for all (i,j,k) with pairwise distinct). In [9], using hypergraphs associated with GTT matrices, it has been shown that for all the vertices of the GTT(n) polytope are half-integral. In this work, we show that these matrices belong to the class of 2-regular matrices and highlight the related optimization implications. Finally, based on our approach and known partial results, conjectures on characterizing the extreme points of the GTT(n) polytope for are provided.
期刊介绍:
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