Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing最新文献

{"title":"A Framework for Distributed Quantum Queries in the CONGEST Model","authors":"Joran van Apeldoorn, Tijn de Vos","doi":"10.1145/3519270.3538413","DOIUrl":"https://doi.org/10.1145/3519270.3538413","url":null,"abstract":"The Quantum CONGEST model is a variant of the CONGEST model, where messages consist of O(log(n)) qubits. In this paper, we give a general framework for implementing quantum query algorithms efficiently in a Quantum CONGEST network, using the concept of parallel-query quantum algorithms. We apply our framework for distributed quantum queries in two settings: problems where data is distributed over the network, and graph theoretical problems where the network defines the input. The first setting is slightly unusual in CONGEST but here our results follow almost directly from the quantum query setting. The second setting is more traditional for the CONGEST model but here our framework requires also some classical CONGEST steps to apply. In the setting with distributed data, we show how a network can pick one of k dates for a meeting such that a maximum number of nodes is available, using Õ(√(kD)+D) rounds, with D the network diameter. The classical complexity is linear in k. We also give an efficient algorithm for element distinctness: if all nodes together holds a list of k numbers, we show that the nodes can determine whether there are any duplicates in Õ(k2/3D1/3+D) rounds. Classically this problem requires ~Ω(k+D) rounds. We also generalize the protocol for the distributed Deutsch-Jozsa problem from the two-party setting considered by Buhrman, Cleve, and Wigderson [4] to general networks. This gives a novel separation between exact classical and exact quantum protocols in the CONGEST model. In the setting where the input is the network structure itself, our framework almost directly allows us to recover the Õ(√nD) round diameter computation algorithm of Le Gall and Magniez [21]. We extend this approach to also compute the radius in the same number of rounds, and to give an ε-additive approximation of the average eccentricity in Õ(D3/2/ε) rounds. Finally, we give the first quantum speedups over classical CONGEST for the problems of cycle detection and girth computation. We detect whether a graph has a cycle of length at most k in O(k+(kn)1/2-1/Θ(k)) rounds. For girth computation, we give an Õ(g+(gn)1/2-1/Θ(g)) round algorithm for graphs with girth g, beating the classical Ω(√n) round lower bound by Frischknecht, Holzer, and Wattenhofer [12].","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122990880","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}

{"title":"What Can Be Certified Compactly? Compact local certification of MSO properties in tree-like graphs","authors":"N. Bousquet, Laurent Feuilloley, Théo Pierron","doi":"10.1145/3519270.3538416","DOIUrl":"https://doi.org/10.1145/3519270.3538416","url":null,"abstract":"Local certification consists in assigning labels (called certificates) to the nodes of a network to certify a property of the network or the correctness of a data structure distributed on the network. The verification of this certification must be local: a node typically sees only its neighbors in the network. The main measure of performance of a certification is the size of its certificates. In 2011, Göös and Suomela identified Θ(log n) as a special certificate size: below this threshold little is possible, and several key properties do have certifications of this type. A certification with such small certificates is now called a compact local certification, and it has become the gold standard of the area, similarly to polynomial time for centralized computing. A major question is then to understand which properties have O(log n) certificates, or in other words: what is the power of compact local certification? Recently, a series of papers have proved that several well-known network properties have compact local certifications: planarity, bounded-genus, etc. But one would like to have more general results, i.e. meta-theorems. In the analogous setting of polynomial-time centralized algorithms, a very fruitful approach has been to prove that restricted types of problems can be solved in polynomial time in graphs with restricted structures. These problems are typically those that can be expressed in some logic, and the graph structures are those with bounded width or depth parameters. We take a similar approach and prove several meta-theorems for local certification. More precisely, the logic we use is MSO, the most classic fragment for logics on graphs, where one can quantify over vertices and sets of vertices, and consider adjacency between vertices. We prove the relevance of this choice in the context of local certification by first considering properties of trees. On trees, we prove that MSO properties can be certified with labels of constant size, whereas the typical non-MSO property of isomorphism requires ~Ε(n) size certificates (where ~Ε hides polylogarithmic factors). We then move on to graphs of bounded treedepth, a well-known parameter that basically measures how far a graph is from a star. We first prove that an optimal certification for bounded treedepth uses certificates of size Θ(log n), and then prove that in bounded treedepth graphs, every MSO property has a compact certification. To establish our results, we use a variety of techniques, originating from model checking, tree automata theory, communication complexity, and combinatorics.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121965352","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}

{"title":"The Landscape of Distributed Complexities on Trees and Beyond","authors":"C. Grunau, Václav Rozhon, S. Brandt","doi":"10.1145/3519270.3538452","DOIUrl":"https://doi.org/10.1145/3519270.3538452","url":null,"abstract":"We study the local complexity landscape of locally checkable labeling (LCL) problems on constant-degree graphs with a focus on complexities below log* n. Our contribution is threefold: (1) Our main contribution is that we complete the classification of the complexity landscape of LCL problems on trees in the LOCAL model, by proving that every LCL problem with local complexity o (log* n) has actually complexityO(1). This result improves upon the previous speedup result from o (log log* n) to O(1) by [Chang, Pettie, FOCS 2017].(2) In the related LCA and VOLUME models [Alon, Rubinfeld, Vardi, Xie, SODA 2012, Rubinfeld, Tamir, Vardi, Xie, 2011, Rosenbaum, Suomela, PODC 2020],we prove the same speedup from o (log* n) to O(1) for all constant-degree graphs.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128457820","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}

{"title":"State Complexity of Protocols with Leaders","authors":"Jérôme Leroux","doi":"10.1145/3519270.3538421","DOIUrl":"https://doi.org/10.1145/3519270.3538421","url":null,"abstract":"Population protocols are a model of computation in which an arbitrary number of anonymous finite-memory agents are interacting in order to decide by stable consensus a predicate. In this paper, we focus on the counting predicates that asks, given an initial configuration, whether the number of agents in some initial state i is at least n. In 2018, Blondin, Esparza, and Jaax shown that with a fix number of leaders, there exists infinitely many n for which the counting predicate is stably computable by a protocol with at most O(log log(n)) states. We provide in this paper a matching lower-bound (up to a square root) that improves the inverse-Ackermannian lower-bound presented at PODC in 2021.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115581459","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}

{"title":"Fast and Fair Randomized Wait-Free Locks","authors":"N. Ben-David, G. Blelloch","doi":"10.1145/3519270.3538448","DOIUrl":"https://doi.org/10.1145/3519270.3538448","url":null,"abstract":"We present a randomized approach for wait-free locks with strong bounds on time and fairness in a context in which any process can be arbitrarily delayed. Our approach supports a tryLock operation that is given a set of locks, and code to run when all the locks are acquired. A tryLock operation, or attempt, may fail if there is contention on the locks, in which case the code is not run. Given an upper bound k known to the algorithm on the point contention of any lock, and an upper bound L on the number of locks in a try- Lock's set, a tryLock will succeed in acquiring its locks and running the code with probability at least 1/(kL). It is thus fair. Furthermore, if the maximum step complexity for the code in any lock is T , the attempt will take O(k2L2T ) steps, regardless of whether it succeeds or fails. The attempts are independent, thus if the tryLock is repeatedly retried on failure, it will succeed in O(k3L3T ) expected steps, and with high probability in not much more.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132138242","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}

{"title":"Can't See the Forest for the Trees: Navigating Metric Spaces by Bounded Hop-Diameter Spanners","authors":"Omri Kahalon, Hung Le, Lazar Milenković, Shay Solomon","doi":"10.1145/3519270.3538414","DOIUrl":"https://doi.org/10.1145/3519270.3538414","url":null,"abstract":"Spanners for metric spaces have been extensively studied, perhaps most notably in low-dimensional Euclidean spaces - due to their numerous applications. Euclidean spanners can be viewed as means of compressing the (n2) pairwise distances of a d-dimensional Euclidean space into O(n) = O∈,d (n) spanner edges, so that the spanner distances preserve the original distances to within a factor of 1 + ε, for any ε > 0. Moreover, one can compute such spanners efficiently in the standard centralized and distributed settings. Once the spanner has been computed, it serves as a \"proxy\" overlay network, on which the computation can proceed, which gives rise to huge savings in space and other important quality measures. The original metric enables us to \"navigate\" optimally - a single","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114984561","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}

{"title":"Blunting an Adversary Against Randomized Concurrent Programs with Linearizable Implementations","authors":"H. Attiya, C. Enea, J. Welch","doi":"10.1145/3519270.3538446","DOIUrl":"https://doi.org/10.1145/3519270.3538446","url":null,"abstract":"Atomic shared objects, whose operations take place instantaneously, are a powerful abstraction for designing complex concurrent programs. Since they are not always available, they are typically substituted with software implementations. A prominent condition relating these implementations to their atomic specifications is linearizability, which preserves safety properties of the programs using them. However linearizability does not preserve hyper-properties, which include probabilistic guarantees of randomized programs: an adversary can greatly amplify the probability of a bad outcome, such as nontermination, by manipulating the order of events inside the implementations of the operations. This unwelcome behavior prevents modular reasoning, which is the key benefit provided by the use of linearizable object implementations. A more restrictive property, strong linearizability, does preserve hyper-properties but it is impossible to achieve in many situations. This paper suggests a novel approach to blunting the adversary's additional power that works even in cases where strong linearizability is not achievable. We show that a wide class of linearizable implementations, including well-known ones for registers and snapshots, can be modified to approach the probabilistic guarantees of randomized programs when using atomic objects. The technical approach is to transform the algorithm of each operation of an existing linearizable implementation by repeating a carefully chosen prefix of the operation several times and then randomly choosing which repetition to use subsequently. We prove that the probability of a bad outcome decreases with the number of repetitions, approaching the probability attained when using atomic objects. The class of implementations to which our transformation applies includes the ABD implementation of a shared register using message-passing, the Afek et al. implementation of an atomic snapshot using single-writer registers, the Vitanyi and Awerbuch implementation of a multi-writer register using single-writer registers, and the Israeli and Li implementation of a multi-reader register using single-reader registers, all of which are widely used in asynchronous crash-prone systems.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125176046","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}

{"title":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","authors":"Darek Kowalski, A. Panconesi","doi":"10.1145/2332432","DOIUrl":"https://doi.org/10.1145/2332432","url":null,"abstract":"It is our great pleasure to welcome you to the 2012 ACM Symposium on Principles of Distributed Computing -- PODC'12. This year's symposium continues its tradition of being the premier forum for presentation of research results in the area of theoretical distributed computing. During the years PODC has been the stage where many landmark results that have increased our understanding of this exciting and, in the Internet era, fundamental research endeavor have been presented. In the best tradition of theoretical discovery, the insights that have been provided have not only elucidated fundamental conceptual issues but also found their way in the real world of systems and applications. The mission of the symposium remains that of providing a high quality international forum for the timely dissemination and discussion of ideas at the frontier of current knowledge in the area of theoretical distributed computing. \u0000 \u0000The call for papers attracted 142 submissions from the Americas, Asia, and Europe. The program committee met in Rome and accepted 35 papers and 26 brief announcements that cover a wide variety of topics. In addition, this year the program includes an industrial panel where colleagues from leading technological companies will share with us their experience with the challenges presented by real, large-scale distributed systems. The keynote speech will be by David Peleg, whose outstanding research record sets a gold standard for the field. Finally, this year PODC hosts the ceremony for the 2012 Edsger W. Dijkstra Prize.","PeriodicalId":182444,"journal":{"name":"Proceedings of the 2022 ACM Symposium on Principles of Distributed Computing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133816723","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}