{"title":"关于广义可传递竞赛多面体极值点的刻画","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":"{\"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}","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}
On characterizing the extreme points of the generalized transitive tournament polytope
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:
Electronic Notes in Discrete Mathematics is a venue for the rapid electronic publication of the proceedings of conferences, of lecture notes, monographs and other similar material for which quick publication is appropriate. Organizers of conferences whose proceedings appear in Electronic Notes in Discrete Mathematics, and authors of other material appearing as a volume in the series are allowed to make hard copies of the relevant volume for limited distribution. For example, conference proceedings may be distributed to participants at the meeting, and lecture notes can be distributed to those taking a course based on the material in the volume.