{"title":"The complexity of equivalence problems for commutative grammars","authors":"Dung T. Huynh","doi":"10.1016/S0019-9958(85)80015-2","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper we investigate the computational complexity of the inequivalence problems for commutative grammars. We show that the inequivalence problems for type 0 and context-sensitive commutative grammars are undecidable whereas decidability in nondeterministic exponential-time holds for the classes of regular and context-free commutative grammars. For the latter the inequivalence problems are <em>Σ</em><sup><em>p</em></sup><sub>2</sub>-hard.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"66 1","pages":"Pages 103-121"},"PeriodicalIF":0.0000,"publicationDate":"1985-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(85)80015-2","citationCount":"29","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"信息与控制","FirstCategoryId":"1093","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0019995885800152","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Mathematics","Score":null,"Total":0}
引用次数: 29
Abstract
In this paper we investigate the computational complexity of the inequivalence problems for commutative grammars. We show that the inequivalence problems for type 0 and context-sensitive commutative grammars are undecidable whereas decidability in nondeterministic exponential-time holds for the classes of regular and context-free commutative grammars. For the latter the inequivalence problems are Σp2-hard.