{"title":"遏制UC2RPQ:困难和简单的情况","authors":"Diego Figueira","doi":"10.4230/LIPIcs.ICDT.2020.9","DOIUrl":null,"url":null,"abstract":"We study the containment problem for UC2RPQ, that is, two-way Regular Path Queries, closed under conjunction, projection and union. We show a dichotomy property between PSpace-c and ExpSpace-c based on a property on the underlying graph of queries. We show that for any class C of graphs, the containment problem for queries whose underlying graph is in C is in PSpace if and only if C has bounded bridgewidth. Bridgewidth is a graph measure we introduce to this end, defined as the maximum size of a minimal edge separator of a graph. 2012 ACM Subject Classification Information systems → Graph-based database models; Information systems → Resource Description Framework (RDF); Mathematics of computing → Graph theory; Theory of computation → Formal languages and automata theory","PeriodicalId":90482,"journal":{"name":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","volume":"55 1","pages":"9:1-9:18"},"PeriodicalIF":0.0000,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"9","resultStr":"{\"title\":\"Containment of UC2RPQ: The Hard and Easy Cases\",\"authors\":\"Diego Figueira\",\"doi\":\"10.4230/LIPIcs.ICDT.2020.9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We study the containment problem for UC2RPQ, that is, two-way Regular Path Queries, closed under conjunction, projection and union. We show a dichotomy property between PSpace-c and ExpSpace-c based on a property on the underlying graph of queries. We show that for any class C of graphs, the containment problem for queries whose underlying graph is in C is in PSpace if and only if C has bounded bridgewidth. Bridgewidth is a graph measure we introduce to this end, defined as the maximum size of a minimal edge separator of a graph. 2012 ACM Subject Classification Information systems → Graph-based database models; Information systems → Resource Description Framework (RDF); Mathematics of computing → Graph theory; Theory of computation → Formal languages and automata theory\",\"PeriodicalId\":90482,\"journal\":{\"name\":\"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory\",\"volume\":\"55 1\",\"pages\":\"9:1-9:18\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2020-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"9\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.4230/LIPIcs.ICDT.2020.9\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Database theory-- ICDT : International Conference ... proceedings. International Conference on Database Theory","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.4230/LIPIcs.ICDT.2020.9","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
We study the containment problem for UC2RPQ, that is, two-way Regular Path Queries, closed under conjunction, projection and union. We show a dichotomy property between PSpace-c and ExpSpace-c based on a property on the underlying graph of queries. We show that for any class C of graphs, the containment problem for queries whose underlying graph is in C is in PSpace if and only if C has bounded bridgewidth. Bridgewidth is a graph measure we introduce to this end, defined as the maximum size of a minimal edge separator of a graph. 2012 ACM Subject Classification Information systems → Graph-based database models; Information systems → Resource Description Framework (RDF); Mathematics of computing → Graph theory; Theory of computation → Formal languages and automata theory