Proceedings of the forty-sixth annual ACM symposium on Theory of computing最新文献_第7页

Cops, robbers, and threatening skeletons: padded decomposition for minor-free graphs 警察、强盗和威胁骨架:无次元图的填充分解

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-13 DOI: 10.1145/2591796.2591849

Ittai Abraham, C. Gavoille, Anupam Gupta, Ofer Neiman, Kunal Talwar

引用次数: 53

An efficient parallel solver for SDD linear systems SDD线性系统的高效并行求解器

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-13 DOI: 10.1145/2591796.2591832

Richard Peng, D. Spielman

引用次数: 182

Fingerprinting codes and the price of approximate differential privacy 指纹编码与近似差分隐私的代价

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-13 DOI: 10.1145/2591796.2591877

Mark Bun, Jonathan Ullman, S. Vadhan

{"title":"Fingerprinting codes and the price of approximate differential privacy","authors":"Mark Bun, Jonathan Ullman, S. Vadhan","doi":"10.1145/2591796.2591877","DOIUrl":"https://doi.org/10.1145/2591796.2591877","url":null,"abstract":"We show new lower bounds on the sample complexity of (ε, δ)-differentially private algorithms that accurately answer large sets of counting queries. A counting query on a database D ∈ ({0, 1}d)n has the form \"What fraction of the individual records in the database satisfy the property q?\" We show that in order to answer an arbitrary set Q of » nd counting queries on D to within error ±α it is necessary that [EQUATION] This bound is optimal up to poly-logarithmic factors, as demonstrated by the Private Multiplicative Weights algorithm (Hardt and Rothblum, FOCS'10). It is also the first to show that the sample complexity required for (ε, δ)-differential privacy is asymptotically larger than what is required merely for accuracy, which is O(log |Q|/α2). In addition, we show that our lower bound holds for the specific case of k-way marginal queries (where |Q| = 2k(d/k)) when α is a constant. Our results rely on the existence of short fingerprinting codes (Boneh and Shaw, CRYPTO'95; Tardos, STOC'03), which we show are closely connected to the sample complexity of differentially private data release. We also give a new method for combining certain types of sample complexity lower bounds into stronger lower bounds.","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121146577","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: 188

Are lock-free concurrent algorithms practically wait-free? 无锁并发算法实际上是无等待的吗?

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-13 DOI: 10.1145/2591796.2591836

Dan Alistarh, K. Censor-Hillel, N. Shavit

{"title":"Are lock-free concurrent algorithms practically wait-free?","authors":"Dan Alistarh, K. Censor-Hillel, N. Shavit","doi":"10.1145/2591796.2591836","DOIUrl":"https://doi.org/10.1145/2591796.2591836","url":null,"abstract":"Lock-free concurrent algorithms guarantee that some concurrent operation will always make progress in a finite number of steps. Yet programmers prefer to treat concurrent code as if it were wait-free, guaranteeing that all operations always make progress. Unfortunately, designing wait-free algorithms is generally a very complex task, and the resulting algorithms are not always efficient. While obtaining efficient wait-free algorithms has been a long-time goal for the theory community, most non-blocking commercial code is only lock-free. This paper suggests a simple solution to this problem. We show that, for a large class of lock-free algorithms, under scheduling conditions which approximate those found in commercial hardware architectures, lock-free algorithms behave as if they are wait-free. In other words, programmers can keep on designing simple lock-free algorithms instead of complex wait-free ones, and in practice, they will get wait-free progress. Our main contribution is a new way of analyzing a general class of lock-free algorithms under a stochastic scheduler. Our analysis relates the individual performance of processes with the global performance of the system using Markov chain lifting between a complex per-process chain and a simpler system progress chain. We show that lock-free algorithms are not only wait-free with probability 1, but that in fact a general subset of lock-free algorithms can be closely bounded in terms of the average number of steps required until an operation completes. To the best of our knowledge, this is the first attempt to analyze progress conditions, typically stated in relation to a worst case adversary, in a stochastic model capturing their expected asymptotic behavior.","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130633916","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: 33

Private matchings and allocations 私有匹配和分配

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-12 DOI: 10.1145/2591796.2591826

Justin Hsu, Zhiyi Huang, Aaron Roth, T. Roughgarden, Zhiwei Steven Wu

{"title":"Private matchings and allocations","authors":"Justin Hsu, Zhiyi Huang, Aaron Roth, T. Roughgarden, Zhiwei Steven Wu","doi":"10.1145/2591796.2591826","DOIUrl":"https://doi.org/10.1145/2591796.2591826","url":null,"abstract":"We consider a private variant of the classical allocation problem: given k goods and n agents with individual, private valuation functions over bundles of goods, how can we partition the goods amongst the agents to maximize social welfare? An important special case is when each agent desires at most one good, and specifies her (private) value for each good: in this case, the problem is exactly the maximum-weight matching problem in a bipartite graph. Private matching and allocation problems have not been considered in the differential privacy literature, and for good reason: they are plainly impossible to solve under differential privacy. Informally, the allocation must match agents to their preferred goods in order to maximize social welfare, but this preference is exactly what agents wish to hide! Therefore, we consider the problem under the relaxed constraint of joint differential privacy: for any agent i, no coalition of agents excluding i should be able to learn about the valuation function of agent i. In this setting, the full allocation is no longer published---instead, each agent is told what good to get. We first show that with a small number of identical copies of each good, it is possible to efficiently and accurately solve the maximum weight matching problem while guaranteeing joint differential privacy. We then consider the more general allocation problem, when bidder valuations satisfy the gross substitutes condition. Finally, we prove that the allocation problem cannot be solved to non-trivial accuracy under joint differential privacy without requiring multiple copies of each type of good.","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125146417","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: 84

Primal beats dual on online packing LPs in the random-order model 随机顺序模型下在线包装lp的原始节拍对偶

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-11 DOI: 10.1145/2591796.2591810

Thomas Kesselheim, K. Radke, Andreas Tönnis, Berthold Vöcking

{"title":"Primal beats dual on online packing LPs in the random-order model","authors":"Thomas Kesselheim, K. Radke, Andreas Tönnis, Berthold Vöcking","doi":"10.1145/2591796.2591810","DOIUrl":"https://doi.org/10.1145/2591796.2591810","url":null,"abstract":"We study packing LPs in an online model where the columns are presented to the algorithm in random order. This natural problem was investigated in various recent studies motivated, e.g., by online ad allocations and yield management where rows correspond to resources and columns to requests specifying demands for resources. Our main contribution is a 1 -- O(√(log d/B))-competitive online algorithm. Here d denotes the column sparsity, i.e., the maximum number of resources that occur in a single column, and B denotes the capacity ratio B, i.e., the ratio between the capacity of a resource and the maximum demand for this resource. In other words, we achieve a (1--ε)-approximation if the capacity ratio satisfies B=Ω(logd/ε2), which is known to be best-possible for any (randomized) online algorithms. Our result improves exponentially on previous work with respect to the capacity ratio. In contrast to existing results on packing LP problems, our algorithm does not use dual prices to guide the allocation of resources over time. Instead, the algorithm simply solves, for each request, a scaled version of the partially known primal program and randomly rounds the obtained fractional solution to obtain an integral allocation for this request. We show that this simple algorithmic technique is not restricted to packing LPs with large capacity ratio of order Ω(logd), but it also yields close-to-optimal competitive ratios if the capacity ratio is bounded by a constant. In particular, we prove an upper bound on the competitive ratio of Ω(d--1/(B--1)), for any B ≥ 2. In addition, we show that our approach can be combined with VCG payments and obtain an incentive compatible (1 -- ε)-competitive mechanism for packing LPs with B = Ω(logm/ε;2), where m is the number of constraints. Finally, we apply our technique to the generalized assignment problem for which we obtain the first online algorithm with competitive ratio O(1).","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125430164","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: 131

The matching polytope has exponential extension complexity 匹配多面体具有指数扩展复杂度

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-11 DOI: 10.1145/2591796.2591834

T. Rothvoss

引用次数: 225

Minimum bisection is fixed parameter tractable 最小平分是固定参数可处理的

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-11 DOI: 10.1145/2591796.2591852

Marek Cygan, D. Lokshtanov, Marcin Pilipczuk, Michal Pilipczuk, Saket Saurabh

引用次数: 56

Communication lower bounds via critical block sensitivity 通过临界块灵敏度的通信下限

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-11 DOI: 10.1145/2591796.2591838

Mika Göös, T. Pitassi

{"title":"Communication lower bounds via critical block sensitivity","authors":"Mika Göös, T. Pitassi","doi":"10.1145/2591796.2591838","DOIUrl":"https://doi.org/10.1145/2591796.2591838","url":null,"abstract":"We use critical block sensitivity, a new complexity measure introduced by Huynh and Nordström (STOC 2012), to study the communication complexity of search problems. To begin, we give a simple new proof of the following central result of Huynh and Nordström: if S is a search problem with critical block sensitivity b, then every randomised two-party protocol solving a certain two-party lift of S requires Ω(b) bits of communication. Besides simplicity, our proof has the advantage of generalising to the multi-party setting. We combine these results with new critical block sensitivity lower bounds for Tseitin and Pebbling search problems to obtain the following applications. • Monotone circuit depth: We exhibit a monotone function on n variables whose monotone circuits require depth Ω(n/log n); previously, a bound of Ω(√n was known (Raz and Wigderson, JACM 1992). Moreover, we prove a tight Θ(√n) monotone depth bound for a function in monotone P. This implies an average-case hierarchy theorem within monotone P similar to a result of Filmus et al. (FOCS 2013). • Proof complexity: We prove new rank lower bounds as well as obtain the first length--space lower bounds for semi-algebraic proof systems, including Lovász--Schrijver and Lasserre (SOS) systems. In particular, these results extend and simplify the works of Beame et al. (SICOMP 2007) and Huynh and Nordström.","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127705650","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: 88

From average case complexity to improper learning complexity 从一般的案例复杂度到不适当的学习复杂度

Proceedings of the forty-sixth annual ACM symposium on Theory of computing Pub Date : 2013-11-10 DOI: 10.1145/2591796.2591820

Amit Daniely, N. Linial, S. Shalev-Shwartz

{"title":"From average case complexity to improper learning complexity","authors":"Amit Daniely, N. Linial, S. Shalev-Shwartz","doi":"10.1145/2591796.2591820","DOIUrl":"https://doi.org/10.1145/2591796.2591820","url":null,"abstract":"The basic problem in the PAC model of computational learning theory is to determine which hypothesis classes are effficiently learnable. There is presently a dearth of results showing hardness of learning problems. Moreover, the existing lower bounds fall short of the best known algorithms. The biggest challenge in proving complexity results is to establish hardness of improper learning (a.k.a. representation independent learning). The difficulty in proving lower bounds for improper learning is that the standard reductions from NP-hard problems do not seem to apply in this context. There is essentially only one known approach to proving lower bounds on improper learning. It was initiated in [21] and relies on cryptographic assumptions. We introduce a new technique for proving hardness of improper learning, based on reductions from problems that are hard on average. We put forward a (fairly strong) generalization of Feige's assumption [13] about the complexity of refuting random constraint satisfaction problems. Combining this assumption with our new technique yields far reaching implications. In particular, • Learning DNF's is hard. • Agnostically learning halfspaces with a constant approximation ratio is hard. • Learning an intersection of ω(1) halfspaces is hard.","PeriodicalId":123501,"journal":{"name":"Proceedings of the forty-sixth annual ACM symposium on Theory of computing","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124051905","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: 111