{"title":"论图的路径数计算","authors":"F. Botler, R. Cano, M. Sambinelli","doi":"10.1016/j.entcs.2019.08.017","DOIUrl":null,"url":null,"abstract":"<div><p>Gallai (1966) conjectured that the edge set of every graph <em>G</em> on <em>n</em> vertices can be covered by at most ⌈<em>n</em>/2⌉ edge-disjoint paths. Such a covering by edge-disjoint paths is called a <em>path decomposition</em>, and the size of a path decomposition with a minimum number of elements is called the <em>path number</em> of <em>G</em>. Peroche (1984) proved that the problem of computing the path number is NP-Complete; and Constantinou and Ellinas (2018) proved that it is polynomial for a family of complete bipartite graphs. In this paper we present an Integer Linear Programming model for computing the path number of a graph. This allowed us to verify Gallai's Conjecture for a large collection of graphs. As a result, following a work of Heinrich, Natale and Streicher on cycle decompositions (2017), we verify Gallai's Conjecture for graphs with at most 11 vertices; for bipartite graphs with at most 16 vertices; and for regular graphs with at most 14 vertices.</p></div>","PeriodicalId":38770,"journal":{"name":"Electronic Notes in Theoretical Computer Science","volume":"346 ","pages":"Pages 185-197"},"PeriodicalIF":0.0000,"publicationDate":"2019-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.entcs.2019.08.017","citationCount":"1","resultStr":"{\"title\":\"On Computing the Path Number of a Graph\",\"authors\":\"F. Botler, R. Cano, M. Sambinelli\",\"doi\":\"10.1016/j.entcs.2019.08.017\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Gallai (1966) conjectured that the edge set of every graph <em>G</em> on <em>n</em> vertices can be covered by at most ⌈<em>n</em>/2⌉ edge-disjoint paths. Such a covering by edge-disjoint paths is called a <em>path decomposition</em>, and the size of a path decomposition with a minimum number of elements is called the <em>path number</em> of <em>G</em>. Peroche (1984) proved that the problem of computing the path number is NP-Complete; and Constantinou and Ellinas (2018) proved that it is polynomial for a family of complete bipartite graphs. In this paper we present an Integer Linear Programming model for computing the path number of a graph. This allowed us to verify Gallai's Conjecture for a large collection of graphs. As a result, following a work of Heinrich, Natale and Streicher on cycle decompositions (2017), we verify Gallai's Conjecture for graphs with at most 11 vertices; for bipartite graphs with at most 16 vertices; and for regular graphs with at most 14 vertices.</p></div>\",\"PeriodicalId\":38770,\"journal\":{\"name\":\"Electronic Notes in Theoretical Computer Science\",\"volume\":\"346 \",\"pages\":\"Pages 185-197\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2019-08-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/j.entcs.2019.08.017\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Electronic Notes in Theoretical Computer Science\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1571066119300672\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"Computer Science\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electronic Notes in Theoretical Computer Science","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1571066119300672","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Computer Science","Score":null,"Total":0}
Gallai (1966) conjectured that the edge set of every graph G on n vertices can be covered by at most ⌈n/2⌉ edge-disjoint paths. Such a covering by edge-disjoint paths is called a path decomposition, and the size of a path decomposition with a minimum number of elements is called the path number of G. Peroche (1984) proved that the problem of computing the path number is NP-Complete; and Constantinou and Ellinas (2018) proved that it is polynomial for a family of complete bipartite graphs. In this paper we present an Integer Linear Programming model for computing the path number of a graph. This allowed us to verify Gallai's Conjecture for a large collection of graphs. As a result, following a work of Heinrich, Natale and Streicher on cycle decompositions (2017), we verify Gallai's Conjecture for graphs with at most 11 vertices; for bipartite graphs with at most 16 vertices; and for regular graphs with at most 14 vertices.
期刊介绍:
ENTCS 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 and the availability on the electronic media is appropriate. Organizers of conferences whose proceedings appear in ENTCS, 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.