Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing最新文献_第7页

Routing permutations on graphs via matchings 通过匹配路由图上的排列

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167239

N. Alon, F. Graham, R. Graham

引用次数: 98

Cryptographic hardness of distribution-specific learning 特定分布学习的密码硬度

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167197

M. Kharitonov

{"title":"Cryptographic hardness of distribution-specific learning","authors":"M. Kharitonov","doi":"10.1145/167088.167197","DOIUrl":"https://doi.org/10.1145/167088.167197","url":null,"abstract":"We investigate cryptographic lower bounds on the learnability of Boolean formulas and constant depth circuits on the {niform distribution and other specifi; distributions. We first show that weakly learning Boolean formulas and constant depth threshold circuits with membership queries on the uniform distribution in polynomial time is as hard as factoring Blum integers (or inverting RSA, or deciding 1? quadratic residuosity . We formalize the notion of a trivially learnable distri ution and extend these hardness results to all non-trivial distributions. Moreover, we show that under appropriate assumptions on the hardness of factoring, the learnability of Boolean formulas and constant depth threshold circuits on any distribution is characterized by the distribution’s Renyi entropy. Furthermore, we show that a sub-exponential lower bound for factoring implies a Q(2’Og@ ‘‘) lower bound (for some constant ~) for learning Boolean circuits of depth d on the uniform distribution (with membership queries), which matches the upper bound of Linial, M ansour, and Nisan [19]. From this we conclude that, assuming such a lower bou-nd for factoring, there is no O(npOLy 10gn ) algorithm to learn all of ACO on the uniform distribution. We observe that, under cryptographic assumptions, all our bounds can be used to establish trade~trs between the running time and the number of samples necessary to learn.","PeriodicalId":280602,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115053486","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}

引用次数: 130

Competitive distributed file allocation 竞争性分布式文件分配

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167142

B. Awerbuch, Y. Bartal, A. Fiat

{"title":"Competitive distributed file allocation","authors":"B. Awerbuch, Y. Bartal, A. Fiat","doi":"10.1145/167088.167142","DOIUrl":"https://doi.org/10.1145/167088.167142","url":null,"abstract":"This paper deals with the file allocation problem [6] concerning the dynamic optimization of communication costs to access data in a distributed environment. We develop a dynamic file re-allocation strategy that adapts on-line to a sequence of read and write requests whose location and relative frequencies are completely unpredictable. This is achieved by replicating the file in response to read requests and migrating the file in response to write requests while paying the associated communications costs, so as to be closer to processors that access it frequently. We develop first explicit deterministic on-line strategy assuming existence of global information about the state of the network; previous (deterministic) solutions were complicated and more expensive. Our solution has (optimal) logarithmic competitive ratio. The paper also contains the first explicit deterministic data migration [7] algorithm achieving the best known competitive ratio for this problem. Using somewhat different technique, we also develop the first deterministic distributed file allocation algorithm (using only local information) with poly-logarithmic competitive ratio against a globally optimized optimal prescient strategy.","PeriodicalId":280602,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132498816","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}

引用次数: 109

Constant time factors do matter 恒定的时间因素确实很重要

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167244

N. Jones

{"title":"Constant time factors do matter","authors":"N. Jones","doi":"10.1145/167088.167244","DOIUrl":"https://doi.org/10.1145/167088.167244","url":null,"abstract":"The constant speedup theorem, so well known from Turing machine based complexity theory, is shown false for a natural imperative programming language I that manipulates tree-structured data. This relieves a tension between general programming practice, where linear factors are essential, and complexity theory, where linear time changes are traditionally regarded as trivial. Specifically, there is a constant b such that for any a > 0 there is a set X recognizable in time a · b · n but not in time a · n. Thus LIN, the collection of all sets recognizable in linear time by deterministic I-programs, contains an infinite hierarchy ordered by constant coefficients. Constant hierarchies also exist for larger time bounds T (n), provided they are time-constructable. Second, a problem is exhibited which is complete for the nondeterministic linear time sets NLIN with respect to a natural notion of deterministic linear-time reduction. Third, Kleene’s Second Recursion Theorem in essence shows that for any program p defined with self-reference, there is an equivalent nonreflexive program q. This is proven for an extension I↑ of I. Further, q can be simulated by an I program at most constantly slower than p. Language I↑ allows calls to the language’s own interpretation function, and even to its running time function (without the usual high costs for nested levels of interpretation). The results all hold as well for a stronger language I allowing selective updating of tree-structured data. The results are robust in that classes LIN and NLIN are identical for I , Isu↑, Schonhage’s Storage Modification Machines, Knuth/Tarjan’s pointer machines, and successor RAMs [13,14,11]. where n is the size of the input. DIKU, Department of Computer Science, University of Copenhagen, Universitetsparken 1, DK-2100 Copenhagen East, Denmark, E-mail: neil@diku.dk. If the “more realistic and precise measure” of SMM computation time is used [13], and similarly for the other models.","PeriodicalId":280602,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129934794","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}

引用次数: 46

The biased coin problem 偏置硬币问题

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167164

R. Boppana, Babu O. Narayanan

引用次数: 22

Randomness-optimal unique element isolation, with applications to perfect matching and related problems 随机-最优唯一元素隔离，应用于完美匹配和相关问题

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167213

Suresh Chari, P. Rohatgi, A. Srinivasan

{"title":"Randomness-optimal unique element isolation, with applications to perfect matching and related problems","authors":"Suresh Chari, P. Rohatgi, A. Srinivasan","doi":"10.1145/167088.167213","DOIUrl":"https://doi.org/10.1145/167088.167213","url":null,"abstract":"In this paper, we precisely characterize the randomness complexity of the unique element isolation problem, a crucial step in the RNC algorithm for perfect matching due to Mulmuley, Vazirani & Vazirani[21] and in several other applications. Given a set $S$ and an unknown family $cal F subseteq$ $2^{S}$ with $|cal F| leq$ $Z$, we present a scheme to assign polynomially bounded weights to the elements of $S$, using only $O(log Z + log |S|)$ ransom bits, such that the minimum weight set in $cal F$ is unique with high probability. This generalizes and improves the results of Mulmuley, Vazirani & Vazirani who give a scheme which uses $O(S log S)$ random bits independent of $Z$. We also prove a matching lower bound for the randomness complexity of this problem. This new weight assignment scheme yields a randomness-efficient $RNC^{2}$ algorithm for perfect matching which uses $O(log Z + log n)$ random bits where $Z$ is any given upper bound on the number of perfect matchings in the input graph. This generalizes the result of Grigoriev & Karpinski[11] who present an $NC^{3}$ algorithm when $Z$ is polynomially bounded and also gives an improvement on the running time in this case. The worst-case randomness complexity of our algorithm is $O(n log (m/n))$ random bits, as opposed to the previous bound of $O(m log n)$ bits. Our technique also gives randomness-efficient solutions for several problems in which the unique element isolation tool is used, such as $RNC$ algorithms for variants of matching and basic problems on linear matroids such as matroid intersection and matroid matching. We also obtain a randomness-efficient alternative to the random reduction from $SAT$ to $USAT$, the language of uniquely satisfiable formulas, due to Valiant and Vazirani[32]. This reduction can be derandomized in the case of languages in $F ew P$ to yield new proofs of the results $F ew P subseteq oplus P$ and $F ew P subseteq C_{=} P$.","PeriodicalId":280602,"journal":{"name":"Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing","volume":"131 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130778428","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}

引用次数: 68

Decision trees: old and new results 决策树:新旧结果

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167216

R. Fleischer

引用次数: 10

Time-space trade-offs for undirected st-connectivity on a JAG JAG上无向st-连通性的时空权衡

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167272

J. Edmonds

引用次数: 23

Simulating threshold circuits by majority circuits 用多数电路模拟阈值电路

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167234

M. Goldmann, Marek Karpinski

引用次数: 87

Polynomial space polynomial delay algorithms for listing families of graphs 图族列表的多项式空间多项式延迟算法

Proceedings of the twenty-fifth annual ACM symposium on Theory of Computing Pub Date : 1993-06-01 DOI: 10.1145/167088.167160

L. A. Goldberg

引用次数: 17