An analysis of the alpha-beta pruning algorithm is presented which takes into account both shallow and deep cut-offs. A formula is first developed to measure the average number of terminal nodes examined by the algorithm in a uniform free of degree n and depth d when ties are allowed among the bottom positions: specifically, all bottom values are assumed to be independent identically distributed random variables drawn from a discrete probability distribution. A worst case analysis over all possible probability distributions is then presented by considering the limiting case when the discrete probability distribution tends to a continuous probability distribution. The branching factor of the alpha-beta pruning algorithm is shown to grow with n as &THgr;(n/In n), therefore confirming a claim by Knuth and Moore that deep cut-offs only have a second order effect on the behavior of the algorithm.
{"title":"An analysis of the full alpha-beta pruning algorithm","authors":"G. Baudet","doi":"10.1145/800133.804359","DOIUrl":"https://doi.org/10.1145/800133.804359","url":null,"abstract":"An analysis of the alpha-beta pruning algorithm is presented which takes into account both shallow and deep cut-offs. A formula is first developed to measure the average number of terminal nodes examined by the algorithm in a uniform free of degree n and depth d when ties are allowed among the bottom positions: specifically, all bottom values are assumed to be independent identically distributed random variables drawn from a discrete probability distribution. A worst case analysis over all possible probability distributions is then presented by considering the limiting case when the discrete probability distribution tends to a continuous probability distribution. The branching factor of the alpha-beta pruning algorithm is shown to grow with n as &THgr;(n/In n), therefore confirming a claim by Knuth and Moore that deep cut-offs only have a second order effect on the behavior of the algorithm.","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":"114139743","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}
M. Fischer, R. DeMillo, N. Lynch, W. Burkhard, A. Aho
{"title":"Proceedings of the tenth annual ACM symposium on Theory of computing","authors":"M. Fischer, R. DeMillo, N. Lynch, W. Burkhard, A. Aho","doi":"10.1145/800133","DOIUrl":"https://doi.org/10.1145/800133","url":null,"abstract":"","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":"130990638","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}
Equations f@@@@ = g@@@@ between polynomial time computable functions can be represented by sets of propositional formulas. If f@@@@ = g@@@@ is provable in certain arithmetic systems, then polynomial length proofs of the representing formulas exist in certain propositional systems. Two cases of this phenomenon and a general theory are given.
{"title":"Propositional representation of arithmetic proofs (Preliminary Version)","authors":"M. Dowd","doi":"10.1145/800133.804354","DOIUrl":"https://doi.org/10.1145/800133.804354","url":null,"abstract":"Equations f@@@@ = g@@@@ between polynomial time computable functions can be represented by sets of propositional formulas. If f@@@@ = g@@@@ is provable in certain arithmetic systems, then polynomial length proofs of the representing formulas exist in certain propositional systems. Two cases of this phenomenon and a general theory are given.","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":"117147043","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}
R. Rivest, A. Meyer, D. Kleitman, Karl Winklmann, J. Spencer
We consider the problem of identifying an unknown value x&egr;{1,2,...,n} using only comparisons of x to constants when as many as E of 'the comparisons may receive erroneous answers. For a continuous analogue of this problem we show that there is a unique strategy that is optimal in the worst case. This strategy for the continuous problem is then shown to yield a strategy for the original discrete problem that uses log2n+E.log2log2n+O(E.log2E) comparisons in the worst case. This number is shown to be optimal even if arbitrary “Yes-No” questions are allowed. We show that a modified version of this search problem with errors is equivalent to the problem of finding the minimal root of a set of increasing functions. The modified version is then also shown to be of complexity log2n+E.log2log2n+0(E.log2E).
{"title":"Coping with errors in binary search procedures (Preliminary Report)","authors":"R. Rivest, A. Meyer, D. Kleitman, Karl Winklmann, J. Spencer","doi":"10.1145/800133.804351","DOIUrl":"https://doi.org/10.1145/800133.804351","url":null,"abstract":"We consider the problem of identifying an unknown value x&egr;{1,2,...,n} using only comparisons of x to constants when as many as E of 'the comparisons may receive erroneous answers. For a continuous analogue of this problem we show that there is a unique strategy that is optimal in the worst case. This strategy for the continuous problem is then shown to yield a strategy for the original discrete problem that uses log2n+E.log2log2n+O(E.log2E) comparisons in the worst case. This number is shown to be optimal even if arbitrary “Yes-No” questions are allowed. We show that a modified version of this search problem with errors is equivalent to the problem of finding the minimal root of a set of increasing functions. The modified version is then also shown to be of complexity log2n+E.log2log2n+0(E.log2E).","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":"122824307","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 general model for data compression is presented which includes most data compression systems in the literature as special cases. All macro schemes are based on the principle of finding redundant strings or patterns and replacing them by pointers to a common copy. Different varieties of macro schemes may be defined by varying the interpretation of pointers, for instance, a pointer may indicate a substring of the compressed string, a substring of the original string, or a substring of some other string such as an external dictionary. Other varieties of macros schemes may be defined by restricting the type of overlapping or recursion that may be used. Trade-offs between different varieties of macro schemes, exact lower bounds on the amount of compression obtainable, and the complexity of encoding and decoding are discussed as well as how the work of other authors (such as Lempel-Ziv) relates to this model.
{"title":"The macro model for data compression (Extended Abstract)","authors":"J. Storer, T. G. Szymanski","doi":"10.1145/800133.804329","DOIUrl":"https://doi.org/10.1145/800133.804329","url":null,"abstract":"A general model for data compression is presented which includes most data compression systems in the literature as special cases. All macro schemes are based on the principle of finding redundant strings or patterns and replacing them by pointers to a common copy. Different varieties of macro schemes may be defined by varying the interpretation of pointers, for instance, a pointer may indicate a substring of the compressed string, a substring of the original string, or a substring of some other string such as an external dictionary. Other varieties of macros schemes may be defined by restricting the type of overlapping or recursion that may be used. Trade-offs between different varieties of macro schemes, exact lower bounds on the amount of compression obtainable, and the complexity of encoding and decoding are discussed as well as how the work of other authors (such as Lempel-Ziv) relates to this model.","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":"122892379","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}
For a fixed graph property, the Maximum Subgraph Recognition Problem for the property is: Given a graph G and integer k, does G have a subgraph induced by k vertices which satisfies the property. This paper studies the complexity of this problem for various properties. The principal result is that if the property is any one of a wide class of monotone properties, the Maximum Subgraph Problem is NP-hard. This suggests a promising direction of inquiry into the P = ?NP question.
{"title":"On the complexity of the Maximum Subgraph Problem","authors":"John M. Lewis","doi":"10.1145/800133.804356","DOIUrl":"https://doi.org/10.1145/800133.804356","url":null,"abstract":"For a fixed graph property, the Maximum Subgraph Recognition Problem for the property is: Given a graph G and integer k, does G have a subgraph induced by k vertices which satisfies the property. This paper studies the complexity of this problem for various properties. The principal result is that if the property is any one of a wide class of monotone properties, the Maximum Subgraph Problem is NP-hard. This suggests a promising direction of inquiry into the P = ?NP question.","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":"132378852","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 model of computation based on random access machines operating in parallel and sharing a common memory is presented. The computational power of this model is related to that of traditional models. In particular, deterministic parallel RAM's can accept in polynomial time exactly the sets accepted by polynomial tape bounded Turing machines; nondeterministic RAM's can accept in polynomial time exactly the sets accepted by nondeterministic exponential time bounded Turing machines. Similar results hold for other classes. The effect of limiting the size of the common memory is also considered.
{"title":"Parallelism in random access machines","authors":"S. Fortune, J. Wyllie","doi":"10.1145/800133.804339","DOIUrl":"https://doi.org/10.1145/800133.804339","url":null,"abstract":"A model of computation based on random access machines operating in parallel and sharing a common memory is presented. The computational power of this model is related to that of traditional models. In particular, deterministic parallel RAM's can accept in polynomial time exactly the sets accepted by polynomial tape bounded Turing machines; nondeterministic RAM's can accept in polynomial time exactly the sets accepted by nondeterministic exponential time bounded Turing machines. Similar results hold for other classes. The effect of limiting the size of the common memory is also considered.","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":"132430864","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 new lower bound on the computational complexity of the theory of real addition and several related theories is established: any decision procedure for these theories requires either space 2&egr;n or nondeterministic time 2&egr;n2 for some constant &egr; > O and infinitely many n. The proof is based on the families of languages TISP(T(n),S(n)) which can be recognized simultaneously in time T(n) and space S(n) and the conditions under which they form a hierarchy.
{"title":"On time-space classes and their relation to the theory of real addition","authors":"Anna R. Bruss, A. Meyer","doi":"10.1145/800133.804352","DOIUrl":"https://doi.org/10.1145/800133.804352","url":null,"abstract":"A new lower bound on the computational complexity of the theory of real addition and several related theories is established: any decision procedure for these theories requires either space 2&egr;n or nondeterministic time 2&egr;n2 for some constant &egr; > O and infinitely many n. The proof is based on the families of languages TISP(T(n),S(n)) which can be recognized simultaneously in time T(n) and space S(n) and the conditions under which they form a 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":"129231562","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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