{"title":"Exploiting the Polyhedral Geometry of Stochastic Linear Bilevel Programming","authors":"G. Muñoz, David Salas, Anton Svensson","doi":"10.1007/978-3-031-32726-1_26","DOIUrl":"https://doi.org/10.1007/978-3-031-32726-1_26","url":null,"abstract":"","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126146341","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 Update-and-Stabilize Framework for the Minimum-Norm-Point Problem","authors":"S. Fujishige, Tomonari Kitahara, L. V'egh","doi":"10.1007/978-3-031-32726-1_11","DOIUrl":"https://doi.org/10.1007/978-3-031-32726-1_11","url":null,"abstract":"","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125237364","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":"Compressing Branch-and-Bound Trees","authors":"Gonzalo Muñoz, Joseph Paat, Á. S. Xavier","doi":"10.1007/978-3-031-32726-1_25","DOIUrl":"https://doi.org/10.1007/978-3-031-32726-1_25","url":null,"abstract":"","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131878703","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 Polyhedral Geometry of Truthful Auctions","authors":"M. Joswig, Max Klimm, Sylvain Spitz","doi":"10.48550/arXiv.2211.01907","DOIUrl":"https://doi.org/10.48550/arXiv.2211.01907","url":null,"abstract":"The difference set of an outcome in an auction is the set of types that the auction mechanism maps to the outcome. We give a complete characterization of the geometry of the difference sets that can appear for a dominant strategy incentive compatible multi-unit auction showing that they correspond to regular subdivisions of the unit cube. This observation is then used to construct mechanisms that are robust in the sense that the set of items allocated to a player does change only slightly when the player's reported type is changed slightly.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131045533","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":"Set Selection under Explorable Stochastic Uncertainty via Covering Techniques","authors":"Nicole Megow, Jens Schloter","doi":"10.48550/arXiv.2211.01097","DOIUrl":"https://doi.org/10.48550/arXiv.2211.01097","url":null,"abstract":"Given subsets of uncertain values, we study the problem of identifying the subset of minimum total value (sum of the uncertain values) by querying as few values as possible. This set selection problem falls into the field of explorable uncertainty and is of intrinsic importance therein as it implies strong adversarial lower bounds for a wide range of interesting combinatorial problems such as knapsack and matchings. We consider a stochastic problem variant and give algorithms that, in expectation, improve upon these adversarial lower bounds. The key to our results is to prove a strong structural connection to a seemingly unrelated covering problem with uncertainty in the constraints via a linear programming formulation. We exploit this connection to derive an algorithmic framework that can be used to solve both problems under uncertainty, obtaining nearly tight bounds on the competitive ratio. This is the first non-trivial stochastic result concerning the sum of unknown values without further structure known for the set. With our novel methods, we lay the foundations for solving more general problems in the area of explorable uncertainty.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122237247","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}
Sander Borst, D. Dadush, Sophie Huiberts, Danish Kashaev
{"title":"A nearly optimal randomized algorithm for explorable heap selection","authors":"Sander Borst, D. Dadush, Sophie Huiberts, Danish Kashaev","doi":"10.48550/arXiv.2210.05982","DOIUrl":"https://doi.org/10.48550/arXiv.2210.05982","url":null,"abstract":"Explorable heap selection is the problem of selecting the $n$th smallest value in a binary heap. The key values can only be accessed by traversing through the underlying infinite binary tree, and the complexity of the algorithm is measured by the total distance traveled in the tree (each edge has unit cost). This problem was originally proposed as a model to study search strategies for the branch-and-bound algorithm with storage restrictions by Karp, Saks and Widgerson (FOCS '86), who gave deterministic and randomized $ncdot exp(O(sqrt{log{n}}))$ time algorithms using $O(log(n)^{2.5})$ and $O(sqrt{log n})$ space respectively. We present a new randomized algorithm with running time $O(nlog(n)^3)$ using $O(log n)$ space, substantially improving the previous best randomized running time at the expense of slightly increased space usage. We also show an $Omega(log(n)n/log(log(n)))$ for any algorithm that solves the problem in the same amount of space, indicating that our algorithm is nearly optimal.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123347035","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}
Sabrina Bruckmeier, Christoph Hunkenschröder, R. Weismantel
{"title":"Sparse Approximation Over the Cube","authors":"Sabrina Bruckmeier, Christoph Hunkenschröder, R. Weismantel","doi":"10.48550/arXiv.2210.02738","DOIUrl":"https://doi.org/10.48550/arXiv.2210.02738","url":null,"abstract":"This paper presents an anlysis of the NP-hard minimization problem $min {|b - Ax|_2: x in [0,1]^n, | text{supp}(x) | leq sigma}$, where $text{supp}(x) = {i in [n]: x_i neq 0}$ and $sigma$ is a positive integer. The object of investigation is a natural relaxation where we replace $| text{supp}(x) | leq sigma$ by $sum_i x_i leq sigma$. Our analysis includes a probabilistic view on when the relaxation is exact. We also consider the problem from a deterministic point of view and provide a bound on the distance between the images of optimal solutions of the original problem and its relaxation under $A$. This leads to an algorithm for generic matrices $A in mathbb{Z}^{m times n}$ and achieves a polynomial running time provided that $m$ and $|A|_{infty}$ are fixed.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121421297","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":"On the Correlation Gap of Matroids","authors":"Edin Husi'c, Zhuan Khye Koh, Georg Loho, L. V'egh","doi":"10.48550/arXiv.2209.09896","DOIUrl":"https://doi.org/10.48550/arXiv.2209.09896","url":null,"abstract":"A set function can be extended to the unit cube in various ways; the correlation gap measures the ratio between two natural extensions. This quantity has been identified as the performance guarantee in a range of approximation algorithms and mechanism design settings. It is known that the correlation gap of a monotone submodular function is at least $1-1/e$, and this is tight for simple matroid rank functions. We initiate a fine-grained study of the correlation gap of matroid rank functions. In particular, we present an improved lower bound on the correlation gap as parametrized by the rank and girth of the matroid. We also show that for any matroid, the correlation gap of its weighted matroid rank function is minimized under uniform weights. Such improved lower bounds have direct applications for submodular maximization under matroid constraints, mechanism design, and contention resolution schemes.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131276416","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":"Optimal General Factor Problem and Jump System Intersection","authors":"Yusuke Kobayashi","doi":"10.48550/arXiv.2209.00779","DOIUrl":"https://doi.org/10.48550/arXiv.2209.00779","url":null,"abstract":"In the optimal general factor problem, given a graph $G=(V, E)$ and a set $B(v) subseteq mathbb Z$ of integers for each $v in V$, we seek for an edge subset $F$ of maximum cardinality subject to $d_F(v) in B(v)$ for $v in V$, where $d_F(v)$ denotes the number of edges in $F$ incident to $v$. A recent crucial work by Dudycz and Paluch shows that this problem can be solved in polynomial time if each $B(v)$ has no gap of length more than one. While their algorithm is very simple, its correctness proof is quite complicated. In this paper, we formulate the optimal general factor problem as the jump system intersection, and reveal when the algorithm by Dudycz and Paluch can be applied to this abstract form of the problem. By using this abstraction, we give another correctness proof of the algorithm, which is simpler than the original one. We also extend our result to the valuated case.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133145355","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}
Franziska Eberle, Anupam Gupta, Nicole Megow, Benjamin Moseley, Rudy Zhou
{"title":"Configuration Balancing for Stochastic Requests","authors":"Franziska Eberle, Anupam Gupta, Nicole Megow, Benjamin Moseley, Rudy Zhou","doi":"10.48550/arXiv.2208.13702","DOIUrl":"https://doi.org/10.48550/arXiv.2208.13702","url":null,"abstract":"The configuration balancing problem with stochastic requests generalizes many well-studied resource allocation problems such as load balancing and virtual circuit routing. In it, we have $m$ resources and $n$ requests. Each request has multiple possible configurations, each of which increases the load of each resource by some amount. The goal is to select one configuration for each request to minimize the makespan: the load of the most-loaded resource. In our work, we focus on a stochastic setting, where we only know the distribution for how each configuration increases the resource loads, learning the realized value only after a configuration is chosen. We develop both offline and online algorithms for configuration balancing with stochastic requests. When the requests are known offline, we give a non-adaptive policy for configuration balancing with stochastic requests that $O(frac{log m}{log log m})$-approximates the optimal adaptive policy. In particular, this closes the adaptivity gap for this problem as there is an asymptotically matching lower bound even for the very special case of load balancing on identical machines. When requests arrive online in a list, we give a non-adaptive policy that is $O(log m)$ competitive. Again, this result is asymptotically tight due to information-theoretic lower bounds for very special cases (e.g., for load balancing on unrelated machines). Finally, we show how to leverage adaptivity in the special case of load balancing on related machines to obtain a constant-factor approximation offline and an $O(log log m)$-approximation online. A crucial technical ingredient in all of our results is a new structural characterization of the optimal adaptive policy that allows us to limit the correlations between its decisions.","PeriodicalId":421894,"journal":{"name":"Conference on Integer Programming and Combinatorial Optimization","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130202678","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}