Towards Tight Bounds for the Streaming Set Cover Problem

We consider the classic Set Cover problem in the data stream model. For n elements and m sets (m ≥ n) we give a O(1/δ)-pass algorithm with a strongly sub-linear ~O(mn[superscript δ]) space and logarithmic approximation factor. This yields a significant improvement over the earlier algorithm of Demai...

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Main Authors: Har-Peled, Sariel, Indyk, Piotr, Mahabadi, Sepideh, Vakilian, Ali
Other Authors: Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Format: Article
Language:en_US
Published: Association for Computing Machinery 2018
Online Access:http://hdl.handle.net/1721.1/113829
https://orcid.org/0000-0002-7983-9524
https://orcid.org/0000-0001-5049-7594
https://orcid.org/0000-0001-5004-8991
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author Har-Peled, Sariel
Indyk, Piotr
Mahabadi, Sepideh
Vakilian, Ali
author2 Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
author_facet Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Har-Peled, Sariel
Indyk, Piotr
Mahabadi, Sepideh
Vakilian, Ali
author_sort Har-Peled, Sariel
collection MIT
description We consider the classic Set Cover problem in the data stream model. For n elements and m sets (m ≥ n) we give a O(1/δ)-pass algorithm with a strongly sub-linear ~O(mn[superscript δ]) space and logarithmic approximation factor. This yields a significant improvement over the earlier algorithm of Demaine et al. [10] that uses exponentially larger number of passes. We complement this result by showing that the tradeoff between the number of passes and space exhibited by our algorithm is tight, at least when the approximation factor is equal to 1. Specifically, we show that any algorithm that computes set cover exactly using ({1 over 2δ}-1) passes must use ~Ω(mn[superscript δ]) space in the regime of m=O(n). Furthermore, we consider the problem in the geometric setting where the elements are points in R[superscript 2] and sets are either discs, axis-parallel rectangles, or fat triangles in the plane, and show that our algorithm (with a slight modification) uses the optimal ~O(n) space to find a logarithmic approximation in O(1/δ) passes. Finally, we show that any randomized one-pass algorithm that distinguishes between covers of size 2 and 3 must use a linear (i.e., Ω(mn)) amount of space. This is the first result showing that a randomized, approximate algorithm cannot achieve a space bound that is sublinear in the input size. This indicates that using multiple passes might be necessary in order to achieve sub-linear space bounds for this problem while guaranteeing small approximation factors.
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spelling mit-1721.1/1138292022-10-03T11:09:55Z Towards Tight Bounds for the Streaming Set Cover Problem Har-Peled, Sariel Indyk, Piotr Mahabadi, Sepideh Vakilian, Ali Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Indyk, Piotr Vakilian, Ali Mahabadi, Sepideh We consider the classic Set Cover problem in the data stream model. For n elements and m sets (m ≥ n) we give a O(1/δ)-pass algorithm with a strongly sub-linear ~O(mn[superscript δ]) space and logarithmic approximation factor. This yields a significant improvement over the earlier algorithm of Demaine et al. [10] that uses exponentially larger number of passes. We complement this result by showing that the tradeoff between the number of passes and space exhibited by our algorithm is tight, at least when the approximation factor is equal to 1. Specifically, we show that any algorithm that computes set cover exactly using ({1 over 2δ}-1) passes must use ~Ω(mn[superscript δ]) space in the regime of m=O(n). Furthermore, we consider the problem in the geometric setting where the elements are points in R[superscript 2] and sets are either discs, axis-parallel rectangles, or fat triangles in the plane, and show that our algorithm (with a slight modification) uses the optimal ~O(n) space to find a logarithmic approximation in O(1/δ) passes. Finally, we show that any randomized one-pass algorithm that distinguishes between covers of size 2 and 3 must use a linear (i.e., Ω(mn)) amount of space. This is the first result showing that a randomized, approximate algorithm cannot achieve a space bound that is sublinear in the input size. This indicates that using multiple passes might be necessary in order to achieve sub-linear space bounds for this problem while guaranteeing small approximation factors. 2018-02-20T15:27:33Z 2018-02-20T15:27:33Z 2016-07 Article http://purl.org/eprint/type/ConferencePaper 978-1-4503-4191-2 http://hdl.handle.net/1721.1/113829 Har-Peled, et al. “Towards Tight Bounds for the Streaming Set Cover Problem.” Proceedings of the 35th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems - PODS ’16 (2016), 26 June - 1 July, 2016, San Francisco, California, Association of Computing Machinery, 2016, pp. 371-383. https://orcid.org/0000-0002-7983-9524 https://orcid.org/0000-0001-5049-7594 https://orcid.org/0000-0001-5004-8991 en_US http://dx.doi.org/10.1145/2902251.2902287 Proceedings of the 35th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems - PODS '16 Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Association for Computing Machinery MIT Web Domain
spellingShingle Har-Peled, Sariel
Indyk, Piotr
Mahabadi, Sepideh
Vakilian, Ali
Towards Tight Bounds for the Streaming Set Cover Problem
title Towards Tight Bounds for the Streaming Set Cover Problem
title_full Towards Tight Bounds for the Streaming Set Cover Problem
title_fullStr Towards Tight Bounds for the Streaming Set Cover Problem
title_full_unstemmed Towards Tight Bounds for the Streaming Set Cover Problem
title_short Towards Tight Bounds for the Streaming Set Cover Problem
title_sort towards tight bounds for the streaming set cover problem
url http://hdl.handle.net/1721.1/113829
https://orcid.org/0000-0002-7983-9524
https://orcid.org/0000-0001-5049-7594
https://orcid.org/0000-0001-5004-8991
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