A sequence of monotone switching functions fn:{0,1}n →{0,1}n is constructed, such that the monotone complexity of fn grows faster than O(n2-ε) for any ε>O. Previously the best lower bounds of this nature were several O(n3/2) bounds due to Pratt, Paterson, Mehlhorn/Galil and Savage. Then we discuss the complexity gap between monotone circuits and circuits over the basis {Λ,V,-} computing the functions, which we have examined before. We show, that for several sequences of monotone functions this gap is at least as large as the largest previously proved gap for sequences of explicitely defined monotone functions (the gap,which was proved for the Boolean matrix product).
{"title":"Switching functions whose monotone complexity","authors":"I. Wegener","doi":"10.1145/800133.804342","DOIUrl":"https://doi.org/10.1145/800133.804342","url":null,"abstract":"A sequence of monotone switching functions fn:{0,1}n →{0,1}n is constructed, such that the monotone complexity of fn grows faster than O(n2-ε) for any ε>O. Previously the best lower bounds of this nature were several O(n3/2) bounds due to Pratt, Paterson, Mehlhorn/Galil and Savage. Then we discuss the complexity gap between monotone circuits and circuits over the basis {Λ,V,-} computing the functions, which we have examined before. We show, that for several sequences of monotone functions this gap is at least as large as the largest previously proved gap for sequences of explicitely defined monotone functions (the gap,which was proved for the Boolean matrix product).","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115365352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A theory of subrecursive indexings is developed, with emphasis on relationships between reducibilities, uniform simulation, and diagonalization.
发展了一种子递归索引理论，重点讨论了可约性、均匀模拟和对角化之间的关系。
{"title":"Indexing of subrecursive classes","authors":"D. Kozen","doi":"10.1145/800133.804358","DOIUrl":"https://doi.org/10.1145/800133.804358","url":null,"abstract":"A theory of subrecursive indexings is developed, with emphasis on relationships between reducibilities, uniform simulation, and diagonalization.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127349477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the problem of finding a homeomorphic image of a “pattern” graph H in a larger input graph G. We view this problem as finding specified sets of edge disjoint or node disjoint paths in G. Our main result is a linear time algorithm to determine if there exists a simple cycle containing three given nodes in G; here H is a triangle. No polynomial time algorithm for this problem was previously known. We also discuss a variety of reductions between related versions of this problem and a number of open problems.
{"title":"The subgraph homeomorphism problem","authors":"A. LaPaugh, R. Rivest","doi":"10.1145/800133.804330","DOIUrl":"https://doi.org/10.1145/800133.804330","url":null,"abstract":"We investigate the problem of finding a homeomorphic image of a “pattern” graph H in a larger input graph G. We view this problem as finding specified sets of edge disjoint or node disjoint paths in G. Our main result is a linear time algorithm to determine if there exists a simple cycle containing three given nodes in G; here H is a triangle. No polynomial time algorithm for this problem was previously known. We also discuss a variety of reductions between related versions of this problem and a number of open problems.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122619931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper extends our earlier work on abstract data types by providing an algebraic treatment of parametrized data types (e.g., sets-of-(), stacks-of-(), etc.), as well as answering a number of questions on the power and limitations of algebraic specification techniques. In brief: we investigate the “hidden function” problem (the need to include operations in specifications which we want to be hidden from the user); we prove that conditional specifications are inherently more powerful than equational specifications; we show that parameterized specifications must contain “side conditions” (e.g., that finite-sets-of-d requires an equality predicate on d), and we compare the power of the algebraic approach taken here with the more categorical approach of Lehman and Smyth.
{"title":"Data type specification: Parameterization and the power of specification techniques","authors":"J. Thatcher, E. Wagner, J. Wright","doi":"10.1145/800133.804340","DOIUrl":"https://doi.org/10.1145/800133.804340","url":null,"abstract":"This paper extends our earlier work on abstract data types by providing an algebraic treatment of parametrized data types (e.g., sets-of-(), stacks-of-(), etc.), as well as answering a number of questions on the power and limitations of algebraic specification techniques. In brief: we investigate the “hidden function” problem (the need to include operations in specifications which we want to be hidden from the user); we prove that conditional specifications are inherently more powerful than equational specifications; we show that parameterized specifications must contain “side conditions” (e.g., that finite-sets-of-d requires an equality predicate on d), and we compare the power of the algebraic approach taken here with the more categorical approach of Lehman and Smyth.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114222965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We give a new characterization of the set of satisfiable formulae of propositional dynamic logic (PDL) based on the method of tableaux. From it we derive a heuristically efficient goal-directed proof procedure and a complete axiom system for PDL. The proof procedure illustrates a striking connection between natural deduction and symbolic execution. The completeness proof for the axiom system incorporates a method for the automatic synthesis of invariants. We also augment DL with new modalities throughout, during, and preserves, supply a new semantic foundation for DL programs, and show how to extend the satisfiability characterizations for PDL to throughout.
{"title":"A practical decision method for propositional dynamic logic (Preliminary Report)","authors":"V. Pratt","doi":"10.1145/800133.804362","DOIUrl":"https://doi.org/10.1145/800133.804362","url":null,"abstract":"We give a new characterization of the set of satisfiable formulae of propositional dynamic logic (PDL) based on the method of tableaux. From it we derive a heuristically efficient goal-directed proof procedure and a complete axiom system for PDL. The proof procedure illustrates a striking connection between natural deduction and symbolic execution. The completeness proof for the axiom system incorporates a method for the automatic synthesis of invariants. We also augment DL with new modalities throughout, during, and preserves, supply a new semantic foundation for DL programs, and show how to extend the satisfiability characterizations for PDL to throughout.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132001311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This extended abstract is a condensed version of the results presented in two technical reports ([16] and [13]). In [16] a systematic treatment of the relationships between parallel rewriting systems (top-down tree transducer, ETOL system) and two-way machines (2-way gsm, tree-walking automaton, checking stack automaton) is given. Particular attention is paid to the effect of restricting the copying power of these devices. In [13] the results of [16] are employed to show that the iteration of nondeterministic top-down tree transducers, of nondeterministic 2-way gsm's and of control on ETOL systems each gives rise to a proper hierarchy.
{"title":"Tree transducers, L systems and two-way machines (Extended Abstract)","authors":"J. Engelfriet, G. Rozenberg, G. Slutzki","doi":"10.1145/800133.804333","DOIUrl":"https://doi.org/10.1145/800133.804333","url":null,"abstract":"This extended abstract is a condensed version of the results presented in two technical reports ([16] and [13]). In [16] a systematic treatment of the relationships between parallel rewriting systems (top-down tree transducer, ETOL system) and two-way machines (2-way gsm, tree-walking automaton, checking stack automaton) is given. Particular attention is paid to the effect of restricting the copying power of these devices. In [13] the results of [16] are employed to show that the iteration of nondeterministic top-down tree transducers, of nondeterministic 2-way gsm's and of control on ETOL systems each gives rise to a proper hierarchy.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133340194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
we consider optimization problems on complete graphs with edge weights chosen from identical but independent normal distributions. We show some very general techniques for obtaining upper and lower bounds on the asymptotic behavior of these problems. Often, but not always, these bounds are equal, enabling us to state the asymptotic behavior of the maximum. Problems in which the bounds are tight include finding the optimum traveling salesman tour, finding a minimum cost spanning tree, and finding a heaviest clique on k vertices. We then discuss some greedy heuristic algorithms for these problems.
{"title":"Maximization problems on graphs with edge weights chosen from a normal distribution (Extended Abstract)","authors":"G. S. Lueker","doi":"10.1145/800133.804327","DOIUrl":"https://doi.org/10.1145/800133.804327","url":null,"abstract":"we consider optimization problems on complete graphs with edge weights chosen from identical but independent normal distributions. We show some very general techniques for obtaining upper and lower bounds on the asymptotic behavior of these problems. Often, but not always, these bounds are equal, enabling us to state the asymptotic behavior of the maximum. Problems in which the bounds are tight include finding the optimum traveling salesman tour, finding a minimum cost spanning tree, and finding a heaviest clique on k vertices. We then discuss some greedy heuristic algorithms for these problems.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126961199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of deciding whether a given propositional formula in conjunctive normal form is satisfiable has been widely studied. I t is known that, when restricted to formulas having only two literals per clause, this problem has an efficient (polynomial-time) solution. But the same problem on formulas having three literals per clause is NP-complete, and hence probably does not have any efficient solution. In this paper, we consider an infinite class of satisfiability problems which contains these two particular problems as special cases, and show that every member of this class is either polynomial-time decidable or NP-complete. The infinite collection of new NP-complete problems so obtained may prove very useful in finding other new NP-complete problems. The classification of the polynomial-time decidable cases yields new problems that are complete in polynomial time and in nondeterministic log space. We also consider an analogous class of problems, involving quantified formulas, which has the property that every member is either polynomial time decidable or complete in polynomial space.
{"title":"The complexity of satisfiability problems","authors":"T. Schaefer","doi":"10.1145/800133.804350","DOIUrl":"https://doi.org/10.1145/800133.804350","url":null,"abstract":"The problem of deciding whether a given propositional formula in conjunctive normal form is satisfiable has been widely studied. I t is known that, when restricted to formulas having only two literals per clause, this problem has an efficient (polynomial-time) solution. But the same problem on formulas having three literals per clause is NP-complete, and hence probably does not have any efficient solution. In this paper, we consider an infinite class of satisfiability problems which contains these two particular problems as special cases, and show that every member of this class is either polynomial-time decidable or NP-complete. The infinite collection of new NP-complete problems so obtained may prove very useful in finding other new NP-complete problems. The classification of the polynomial-time decidable cases yields new problems that are complete in polynomial time and in nondeterministic log space. We also consider an analogous class of problems, involving quantified formulas, which has the property that every member is either polynomial time decidable or complete in polynomial space.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123014363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper represents a continuation of work in [LBI] and [LB2] directed toward the development of a unified, relative model for complexity theory. The earlier papers establish a simple, natural and fairly general model, and demonstrated its attractiveness by using it to state and prove a variety of technical results. The present paper uses the same model but deals more specifically with the problems involved in stating complexity bounds in a usable closed form for arbitrary operations on arbitrary data types. Work currently in progress is directed toward similar unified treatment of complexity of data structures.
{"title":"Straight-line program length as a parameter for complexity measures","authors":"N. Lynch","doi":"10.1145/800133.804343","DOIUrl":"https://doi.org/10.1145/800133.804343","url":null,"abstract":"This paper represents a continuation of work in [LBI] and [LB2] directed toward the development of a unified, relative model for complexity theory. The earlier papers establish a simple, natural and fairly general model, and demonstrated its attractiveness by using it to state and prove a variety of technical results. The present paper uses the same model but deals more specifically with the problems involved in stating complexity bounds in a usable closed form for arbitrary operations on arbitrary data types. Work currently in progress is directed toward similar unified treatment of complexity of data structures.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116267588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The algorithm of the title is presented. It runs in time bounded by a polynomial in the number of the edges of the graph.
给出了标题的算法。它的运行时间以图边数的多项式为界。
{"title":"An efficient algorithm for determining whether a cubic graph is toroidal","authors":"I. Filotti","doi":"10.1145/800133.804341","DOIUrl":"https://doi.org/10.1145/800133.804341","url":null,"abstract":"The algorithm of the title is presented. It runs in time bounded by a polynomial in the number of the edges of the graph.","PeriodicalId":313820,"journal":{"name":"Proceedings of the tenth annual ACM symposium on Theory of computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122518750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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