信息与控制Pub Date : 1986-10-01DOI: 10.1016/S0019-9958(86)80018-3
Stanislav ák
{"title":"An exponential lower bound for real-time branching programs","authors":"Stanislav ák","doi":"10.1016/S0019-9958(86)80018-3","DOIUrl":"10.1016/S0019-9958(86)80018-3","url":null,"abstract":"<div><p>Branching programs are a general model of sequential computation. One of their computational features is their possibility to question (repeatedly) the information from each input bit. Real-time branching programs make at most <em>n</em> questions when computing on an input of length <em>n</em>. The restriction “real-time” allows to find a simple language which requires the lower bound 2<sup>√2<em>n</em>/8</sup> on memory (= the state space).</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"71 1","pages":"Pages 87-94"},"PeriodicalIF":0.0,"publicationDate":"1986-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80018-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90083827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80004-3
Péter Gács
{"title":"Every sequence is reducible to a random one","authors":"Péter Gács","doi":"10.1016/S0019-9958(86)80004-3","DOIUrl":"10.1016/S0019-9958(86)80004-3","url":null,"abstract":"<div><p>Every infinite sequence is Turing-reducible to an infinite sequence which is random in the sense of Martin-Löf.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 186-192"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80004-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74333698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80001-8
Sergiu Hart, Micha Sharir
{"title":"Probabilistic propositional temporal logics","authors":"Sergiu Hart, Micha Sharir","doi":"10.1016/S0019-9958(86)80001-8","DOIUrl":"10.1016/S0019-9958(86)80001-8","url":null,"abstract":"<div><p>We present two (closely-related) propositional probabilistic temporal logics based on temporal logics of branching time as introduced by Ben-Ari, Pnueli, and Manna (<em>Acta Inform.</em> <strong>20</strong> (1983), 207–226), Emerson and Halpern (“Proceedings, 14th ACM Sympos. Theory of Comput.,” 1982, pp. 169–179, and Emerson and Clarke (<em>Sci. Comput. Program.</em> <strong>2</strong> (1982), 241–266). The first logic, <em>PTL<sub>f</sub></em>, is interpreted over finite models, while the second logic, <em>PTL<sub>b</sub></em>, which is an extension of the first one, is interpreted over infinite models with transition probabilities bounded away from 0. The logic <em>PTL<sub>f</sub></em> allows us to reason about finite-state sequential probabilistic programs, and the logic <em>PTL<sub>b</sub></em> allows us to reason about (finite-state) concurrent probabilistic programs, without any explicit reference to the actual values of their state-transition probabilities. A generalization of the tableau method yields deterministic single-exponential time decision procedures for our logics, and complete axiomatizations of them are given. Several meta-results, including the absence of a finite-model property for <em>PTL<sub>b</sub></em>, and the connection between satisfiable formulae of <em>PTL<sub>b</sub></em> and finite state concurrent probabilistic programs, are also discussed.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 97-155"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80001-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76375540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80003-1
Etsuro Moriya, Shigeki Iwata, Takumi Kasai
{"title":"A note on some simultaneous relations among time, space, and reversal for single work tape nondeterministic turing machines","authors":"Etsuro Moriya, Shigeki Iwata, Takumi Kasai","doi":"10.1016/S0019-9958(86)80003-1","DOIUrl":"10.1016/S0019-9958(86)80003-1","url":null,"abstract":"<div><p>Simultaneous resource bounded complexity classes for nondeterministic single worktape off-line Turing machines are considered such as time-space bounded classes, denoted by NTISP<sub>1</sub>(<em>T, S</em>), reversal-space bounded classes, denoted by NRESP<sub>1</sub>(<em>R, S</em>), and time-reversal bounded classes, denoted by NTIRE<sub>1</sub>(<em>T, R</em>). It is shown that NRESP<sub>1</sub>(<em>R</em>(<em>n</em>), <em>S</em>(<em>n</em>)) contains NTISP<sub>1</sub>(<em>S</em>(<em>n</em>), <em>R</em>(<em>n</em>)) and is contained in NTISP<sub>1</sub>(<em>R</em>(<em>n</em>) <em>S</em>(<em>n</em>)<em>n</em><sup>2</sup> log <em>n</em>, <em>R</em>(<em>n</em>) log <em>n</em>). The following corollaries follow: (1) the affirmative solution to the nondeterministic single worktape version of the <em>NC</em> = ? <em>SC</em> problem, NTIRE<sub>1</sub>(poly, polylog) = NTISP<sub>1</sub>(poly, polylog), and (2) a reversal-space trade-off, NRESP<sub>1</sub>(polylog, poly) = NRESP<sub>1</sub>(poly, polylog).</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 179-185"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80003-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80116605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80005-5
Georg Lausen, Eljas Soisalon-Soininen , Peter Widmayer
{"title":"Pre-analysis locking","authors":"Georg Lausen, Eljas Soisalon-Soininen , Peter Widmayer","doi":"10.1016/S0019-9958(86)80005-5","DOIUrl":"10.1016/S0019-9958(86)80005-5","url":null,"abstract":"<div><p>A safe and deadlock free locking policy is introduced, called pre-analysis locking. A transaction system with no lock and unlock operations in the transactions is first being analyzed by the pre-analysis locking algorithm. Then, the result of this analysis is used to insert lock and unlock operations into the transactions with the goal of achieving a degree of concurrency as high as possible. However, pre-analysis locking is merely a heuristic operating in polynomial time; therefore, it is not guaranteed to perform optimally in all cases. In comparison with 2-phase locking, neither pre-analysis locking nor 2-phase locking dominates the other; there exist transaction systems in which pre-analysis locking allows for more concurrency than any 2-phase locking policy, but there are also cases in which a 2-phase locking policy allows for more concurrency than pre-analysis locking. However, preanalysis locking is free from deadlocks, in general.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 193-215"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80005-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72438243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80006-7
Larry Denenberg , Yuri Gurevich , Saharon Shelah
{"title":"Definability by constant-depth polynomial-size circuits","authors":"Larry Denenberg , Yuri Gurevich , Saharon Shelah","doi":"10.1016/S0019-9958(86)80006-7","DOIUrl":"10.1016/S0019-9958(86)80006-7","url":null,"abstract":"<div><p>A function of boolean arguments is <em>symmetric</em> if its value depends solely on the number of 1's among its arguments. In the first part of this paper we partially characterize those symmetric functions that can be computed by constant-depth polynomial-size sequences of boolean circuits, and discuss the complete characterization. (We treat both uniform and non-uniform sequences of circuits.) Our results imply that these circuits can compute functions that are not definable in first-order logic. In the second part of the paper we generalize from circuits computing symmetric functions to circuits recognizing first-order structures. By imposing fairly natural restrictions we develop a circuit model with precisely the power of first-order logic: a class of structures is first-order definable if and only if it can be recognized by a constant-depth polynomial-time sequence of such circuits.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 216-240"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80006-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77294006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80002-X
James S. Royer
{"title":"Inductive inference of approximations","authors":"James S. Royer","doi":"10.1016/S0019-9958(86)80002-X","DOIUrl":"10.1016/S0019-9958(86)80002-X","url":null,"abstract":"<div><p>In this paper we investigate inductive inference identification criteria which permit infinitely many errors in explanations, but which require that the “density” of these errors be no more than a certain, prespectified amount. We introduce three hierarchies of such criteria, each of which has the same order type as the real unit interval. These three hierarchies are progressively more strict in the way they measure density of errors of explanations. The strictest of the three turns out to have all of its members, save one, incomparable to the identification criterion which permits finitely many errors in explanations.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Pages 156-178"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80002-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83418796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-08-01DOI: 10.1016/S0019-9958(86)80007-9
{"title":"Author index for volume 70","authors":"","doi":"10.1016/S0019-9958(86)80007-9","DOIUrl":"https://doi.org/10.1016/S0019-9958(86)80007-9","url":null,"abstract":"","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 2","pages":"Page 241"},"PeriodicalIF":0.0,"publicationDate":"1986-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80007-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137213591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
信息与控制Pub Date : 1986-07-01DOI: 10.1016/S0019-9958(86)80024-9
Pekka Orponen, Uwe Schöning
{"title":"The density and complexity of polynomial cores for intractable sets","authors":"Pekka Orponen, Uwe Schöning","doi":"10.1016/S0019-9958(86)80024-9","DOIUrl":"10.1016/S0019-9958(86)80024-9","url":null,"abstract":"<div><p>Let <em>A</em> be a recursive problem not in <em>P</em>. Lynch has shown that <em>A</em> then has an infinite recursive <em>polynomial complexity core</em>. This is a collection <em>C</em> of instances of <em>A</em> such that every algorithm deciding <em>A</em> needs more than polynomial time almost everywhere on <em>C</em>. We investigate the complexity of recognizing the instances in such a core, and show that every recursive problem <em>A</em> not in <em>P</em> has an infinite core recognizable in subexponential time. We further study how dense the core sets for <em>A</em> can be, under various assumptions about the structure of <em>A</em>. Our main results in this direction are that if <em>P</em> ≠ <em>NP</em>, then <em>NP</em>-complete problems have polynomially nonsparse cores recognizable in subexponential time, and that EXPTIME-complete problems have cores of exponential density recognizable in exponential time.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"70 1","pages":"Pages 54-68"},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(86)80024-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77593501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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