{"title":"Conjunctive degrees and cylinders","authors":"Irakli Chitaia, Roland Omanadze, Andrea Sorbi","doi":"10.1093/logcom/exad064","DOIUrl":null,"url":null,"abstract":"Abstract In this article, we define and study the notion of a $(c,c_{1})$-cylinder, which turns out to be very useful instrument for investigating the relationships between conjunctive reducibility ($c$-reducibility) and its injective version $c_{1}$-reducibility. Using this notion, we prove the following results: (i) Neither hypersimple sets nor hemimaximal sets can be $(c,c_{1})$-cylinders; (ii) The $c$-degree of a noncomputable c.e. set contains either only one or infinitely many noncomputable $c_{1}$-degrees; (iii) the $c$-degree of either a hemimaximal set or a hypersimple set contains infinitely many noncomputable $c_{1}$-degrees.","PeriodicalId":50162,"journal":{"name":"Journal of Logic and Computation","volume":"72 2","pages":"0"},"PeriodicalIF":0.7000,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Logic and Computation","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1093/logcom/exad064","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"COMPUTER SCIENCE, THEORY & METHODS","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract In this article, we define and study the notion of a $(c,c_{1})$-cylinder, which turns out to be very useful instrument for investigating the relationships between conjunctive reducibility ($c$-reducibility) and its injective version $c_{1}$-reducibility. Using this notion, we prove the following results: (i) Neither hypersimple sets nor hemimaximal sets can be $(c,c_{1})$-cylinders; (ii) The $c$-degree of a noncomputable c.e. set contains either only one or infinitely many noncomputable $c_{1}$-degrees; (iii) the $c$-degree of either a hemimaximal set or a hypersimple set contains infinitely many noncomputable $c_{1}$-degrees.
期刊介绍:
Logic has found application in virtually all aspects of Information Technology, from software engineering and hardware to programming and artificial intelligence. Indeed, logic, artificial intelligence and theoretical computing are influencing each other to the extent that a new interdisciplinary area of Logic and Computation is emerging.
The Journal of Logic and Computation aims to promote the growth of logic and computing, including, among others, the following areas of interest: Logical Systems, such as classical and non-classical logic, constructive logic, categorical logic, modal logic, type theory, feasible maths.... Logical issues in logic programming, knowledge-based systems and automated reasoning; logical issues in knowledge representation, such as non-monotonic reasoning and systems of knowledge and belief; logics and semantics of programming; specification and verification of programs and systems; applications of logic in hardware and VLSI, natural language, concurrent computation, planning, and databases. The bulk of the content is technical scientific papers, although letters, reviews, and discussions, as well as relevant conference reviews, are included.