{"title":"Adversarially Robust Streaming via Dense-Sparse Trade-offs","authors":"Omri Ben-Eliezer, T. Eden, Krzysztof Onak","doi":"10.1137/1.9781611977066.15","DOIUrl":"https://doi.org/10.1137/1.9781611977066.15","url":null,"abstract":"A streaming algorithm is adversarially robust if it is guaranteed to perform correctly even in the presence of an adaptive adversary. Recently, several sophisticated frameworks for robustification of classical streaming algorithms have been developed. One of the main open questions in this area is whether efficient adversarially robust algorithms exist for moment estimation problems under the turnstile streaming model, where both insertions and deletions are allowed. So far, the best known space complexity for streams of length $m$, achieved using differential privacy (DP) based techniques, is of order $tilde{O}(m^{1/2})$ for computing a constant-factor approximation with high constant probability. In this work, we propose a new simple approach to tracking moments by alternating between two different regimes: a sparse regime, in which we can explicitly maintain the current frequency vector and use standard sparse recovery techniques, and a dense regime, in which we make use of existing DP-based robustification frameworks. The results obtained using our technique break the previous $m^{1/2}$ barrier for any fixed $p$. More specifically, our space complexity for $F_2$-estimation is $tilde{O}(m^{2/5})$ and for $F_0$-estimation, i.e., counting the number of distinct elements, it is $tilde O(m^{1/3})$. All existing robustness frameworks have their space complexity depend multiplicatively on a parameter $lambda$ called the emph{flip number} of the streaming problem, where $lambda = m$ in turnstile moment estimation. The best known dependence in these frameworks (for constant factor approximation) is of order $tilde{O}(lambda^{1/2})$, and it is known to be tight for certain problems. Again, our approach breaks this barrier, achieving a dependence of order $tilde{O}(lambda^{1/2 - c(p)})$ for $F_p$-estimation, where $c(p)>0$ depends only on $p$.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"121 1","pages":"214-227"},"PeriodicalIF":0.0,"publicationDate":"2021-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85226193","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":"An explicit vector algorithm for high-girth MaxCut","authors":"Jessica Thompson, Ojas D. Parekh, Kunal Marwaha","doi":"10.1137/1.9781611977066.17","DOIUrl":"https://doi.org/10.1137/1.9781611977066.17","url":null,"abstract":"We give an approximation algorithm for MaxCut and provide guarantees on the average fraction of edges cut on $d$-regular graphs of girth $geq 2k$. For every $d geq 3$ and $k geq 4$, our approximation guarantees are better than those of all other classical and quantum algorithms known to the authors. Our algorithm constructs an explicit vector solution to the standard semidefinite relaxation of MaxCut and applies hyperplane rounding. It may be viewed as a simplification of the previously best known technique, which approximates Gaussian wave processes on the infinite $d$-regular tree.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"17 1","pages":"238-246"},"PeriodicalIF":0.0,"publicationDate":"2021-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76830098","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":"Faster Exponential Algorithm for Permutation Pattern Matching","authors":"Paweł Gawrychowski, Mateusz Rzepecki","doi":"10.1137/1.9781611977066.21","DOIUrl":"https://doi.org/10.1137/1.9781611977066.21","url":null,"abstract":"The Permutation Pattern Matching problem asks, given two permutations $sigma$ on $n$ elements and $pi$, whether $sigma$ admits a subsequence with the same relative order as $pi$ (or, in the counting version, how many such subsequences are there). This natural problem was shown by Bose, Buss and Lubiw [IPL 1998] to be NP-complete, and hence we should seek exact exponential time solutions. The asymptotically fastest such solution up to date, by Berendsohn, Kozma and Marx [IPEC 2019], works in $mathcal{O}(1.6181^n)$ time. We design a simple and faster $mathcal{O}(1.415^{n})$ time algorithm for both the detection and the counting version. We also prove that this is optimal among a certain natural class of algorithms.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"51 1","pages":"279-284"},"PeriodicalIF":0.0,"publicationDate":"2021-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79324376","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":"Uniformity Testing in the Shuffle Model: Simpler, Better, Faster","authors":"C. Canonne, Hongyi Lyu","doi":"10.1137/1.9781611977066.13","DOIUrl":"https://doi.org/10.1137/1.9781611977066.13","url":null,"abstract":"Uniformity testing, or testing whether independent observations are uniformly distributed, is the prototypical question in distribution testing. Over the past years, a line of work has been focusing on uniformity testing under privacy constraints on the data, and obtained private and data-efficient algorithms under various privacy models such as central differential privacy (DP), local privacy (LDP), pan-privacy, and, very recently, the shuffle model of differential privacy. In this work, we considerably simplify the analysis of the known uniformity testing algorithm in the shuffle model, and, using a recent result on “privacy amplification via shuffling,” provide an alternative algorithm attaining the same guarantees with an elementary and streamlined argument.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"71 1","pages":"182-202"},"PeriodicalIF":0.0,"publicationDate":"2021-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78640616","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}
F. Grandoni, Chris Schwiegelshohn, Shay Solomon, Amitai Uzrad
{"title":"Maintaining an EDCS in General Graphs: Simpler, Density-Sensitive and with Worst-Case Time Bounds","authors":"F. Grandoni, Chris Schwiegelshohn, Shay Solomon, Amitai Uzrad","doi":"10.1137/1.9781611977066.2","DOIUrl":"https://doi.org/10.1137/1.9781611977066.2","url":null,"abstract":"In their breakthrough ICALP'15 paper, Bernstein and Stein presented an algorithm for maintaining a $(3/2+epsilon)$-approximate maximum matching in fully dynamic {em bipartite} graphs with a {em worst-case} update time of $O_epsilon(m^{1/4})$; we use the $O_epsilon$ notation to suppress the $epsilon$-dependence. Their main technical contribution was in presenting a new type of bounded-degree subgraph, which they named an {em edge degree constrained subgraph (EDCS)}, which contains a large matching -- of size that is smaller than the maximum matching size of the entire graph by at most a factor of $3/2+epsilon$. They demonstrate that the EDCS can be maintained with a worst-case update time of $O_epsilon(m^{1/4})$, and their main result follows as a direct corollary. In their followup SODA'16 paper, Bernstein and Stein generalized their result for general graphs, achieving the same update time of $O_epsilon(m^{1/4})$, albeit with an amortized rather than worst-case bound. To date, the best {em deterministic} worst-case update time bound for {em any} better-than-2 approximate matching is $O(sqrt{m})$ [Neiman and Solomon, STOC'13], [Gupta and Peng, FOCS'13]; allowing randomization (against an oblivious adversary) one can achieve a much better (still polynomial) update time for approximation slightly below 2 [Behnezhad, Lacki and Mirrokni, SODA'20]. In this work wefootnote{em quasi nanos, gigantium humeris insidentes} simplify the approach of Bernstein and Stein for bipartite graphs, which allows us to generalize it for general graphs while maintaining the same bound of $O_epsilon(m^{1/4})$ on the {em worst-case} update time. Moreover, our approach is {em density-sensitive}: If the {em arboricity} of the dynamic graph is bounded by $alpha$ at all times, then the worst-case update time of the algorithm is $O_epsilon(sqrt{alpha})$.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"os-32 1","pages":"12-23"},"PeriodicalIF":0.0,"publicationDate":"2021-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87413973","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":"A Tighter Relation Between Hereditary Discrepancy and Determinant Lower Bound","authors":"Haotian Jiang, Victor Reis","doi":"10.1137/1.9781611977066.24","DOIUrl":"https://doi.org/10.1137/1.9781611977066.24","url":null,"abstract":"In seminal work, Lovász, Spencer, and Vesztergombi [European J. Combin., 1986] proved a lower bound for the hereditary discrepancy of a matrix A ∈ Rm×n in terms of the maximum |det(B)|1/k over all k × k submatrices B of A. We show algorithmically that this determinant lower bound can be off by at most a factor of O( √ log(m) · log(n)), improving over the previous bound of O(log(mn)· √ log(n)) given by Matoušek [Proc. of the AMS, 2013]. Our result immediately implies herdisc(F1 ∪ F2) ≤ O( √ log(m) · log(n)) · max(herdisc(F1), herdisc(F2)), for any two set systems F1,F2 over [n] satisfying |F1 ∪ F2| = m. Our bounds are tight up to constants when m = O(poly(n)) due to a construction of Pálvölgyi [Discrete Comput. Geom., 2010] or the counterexample to Beck’s three permutation conjecture by Newman, Neiman and Nikolov [FOCS, 2012]. University of Washington, Seattle, USA. jhtdavid@cs.washington.edu. University of Washington, Seattle, USA. voreis@cs.washington.edu.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"61 1","pages":"308-313"},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74206086","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":"Derandomization of Cell Sampling","authors":"Alexander Golovnev, Tom Gur, Igor Shinkar","doi":"10.1137/1.9781611977585.ch26","DOIUrl":"https://doi.org/10.1137/1.9781611977585.ch26","url":null,"abstract":"Since 1989, the best known lower bound on static data structures was Siegel's classical cell sampling lower bound. Siegel showed an explicit problem with $n$ inputs and $m$ possible queries such that every data structure that answers queries by probing $t$ memory cells requires space $sgeqwidetilde{Omega}left(ncdot(frac{m}{n})^{1/t}right)$. In this work, we improve this bound for non-adaptive data structures to $sgeqwidetilde{Omega}left(ncdot(frac{m}{n})^{1/(t-1)}right)$ for all $t geq 2$. For $t=2$, we give a lower bound of $s>m-o(m)$, improving on the bound $s>m/2$ recently proved by Viola over $mathbb{F}_2$ and Siegel's bound $sgeqwidetilde{Omega}(sqrt{mn})$ over other finite fields.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"60 1","pages":"278-284"},"PeriodicalIF":0.0,"publicationDate":"2021-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85873424","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}
Daniel Bertschinger, Nicolas El Maalouly, Tillmann Miltzow, P. Schnider, Simon Weber
{"title":"Topological Art in Simple Galleries","authors":"Daniel Bertschinger, Nicolas El Maalouly, Tillmann Miltzow, P. Schnider, Simon Weber","doi":"10.1137/1.9781611977066.8","DOIUrl":"https://doi.org/10.1137/1.9781611977066.8","url":null,"abstract":"Let P be a simple polygon, then the art gallery problem is looking for a minimum set of points (guards) that can see every point in P. We say two points $$a,bin P$$\u0000 \u0000 a\u0000 ,\u0000 b\u0000 ∈\u0000 P\u0000 \u0000 can see each other if the line segment $${text {seg}} (a,b)$$\u0000 \u0000 seg\u0000 (\u0000 a\u0000 ,\u0000 b\u0000 )\u0000 \u0000 is contained in P. We denote by V(P) the family of all minimum guard placements. The Hausdorff distance makes V(P) a metric space and thus a topological space. We show homotopy-universality, that is, for every semi-algebraic set S there is a polygon P such that V(P) is homotopy equivalent to S. Furthermore, for various concrete topological spaces T, we describe instances I of the art gallery problem such that V(I) is homeomorphic to T.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"31 1","pages":"87-116"},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78017232","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. Balliu, Janne H. Korhonen, F. Kuhn, Henrik Lievonen, D. Olivetti, Shreyas Pai, A. Paz, J. Rybicki, Stefan Schmid, Jan Studen'y, J. Suomela, Jara Uitto
{"title":"Sinkless Orientation Made Simple","authors":"A. Balliu, Janne H. Korhonen, F. Kuhn, Henrik Lievonen, D. Olivetti, Shreyas Pai, A. Paz, J. Rybicki, Stefan Schmid, Jan Studen'y, J. Suomela, Jara Uitto","doi":"10.1137/1.9781611977585.ch17","DOIUrl":"https://doi.org/10.1137/1.9781611977585.ch17","url":null,"abstract":"The sinkless orientation problem plays a key role in understanding the foundations of distributed computing. The problem can be used to separate two fundamental models of distributed graph algorithms, LOCAL and SLOCAL: the locality of sinkless orientation is $Omega(log n)$ in the deterministic LOCAL model and $O(log log n)$ in the deterministic SLOCAL model. Both of these results are known by prior work, but here we give new simple, self-contained proofs for them.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"36 1","pages":"175-191"},"PeriodicalIF":0.0,"publicationDate":"2021-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75379413","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 Quantum Union Bound made easy","authors":"R. O'Donnell, R. Venkateswaran","doi":"10.1137/1.9781611977066.25","DOIUrl":"https://doi.org/10.1137/1.9781611977066.25","url":null,"abstract":"We give a short proof of Gao’s Quantum Union Bound and Gentle Sequential Measurement theorems.","PeriodicalId":93491,"journal":{"name":"Proceedings of the SIAM Symposium on Simplicity in Algorithms (SOSA)","volume":"102 1","pages":"314-320"},"PeriodicalIF":0.0,"publicationDate":"2021-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79428762","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}