{"title":"Online class cover problem","authors":"Minati De , Anil Maheshwari , Ratnadip Mandal","doi":"10.1016/j.comgeo.2024.102120","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, we study the online class cover problem where a (finite or infinite) family <span><math><mi>F</mi></math></span> of geometric objects and a set <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>r</mi></mrow></msub></math></span> of red points in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> are given a prior, and blue points from <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> arrives one after another. Upon the arrival of a blue point, the online algorithm must make an irreversible decision to cover it with objects from <span><math><mi>F</mi></math></span> that do not cover any points of <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>r</mi></mrow></msub></math></span>. The objective of the problem is to place a minimum number of objects. When <span><math><mi>F</mi></math></span> consists of axis-parallel unit squares in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, we prove that the competitive ratio of any deterministic online algorithm is <span><math><mi>Ω</mi><mo>(</mo><mi>log</mi><mo></mo><mo>|</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>|</mo><mo>)</mo></math></span>, and also propose an <span><math><mi>O</mi><mo>(</mo><mi>log</mi><mo></mo><mo>|</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>|</mo><mo>)</mo></math></span>-competitive deterministic algorithm for the problem.</p></div>","PeriodicalId":51001,"journal":{"name":"Computational Geometry-Theory and Applications","volume":null,"pages":null},"PeriodicalIF":0.4000,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Computational Geometry-Theory and Applications","FirstCategoryId":"94","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0925772124000427","RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper, we study the online class cover problem where a (finite or infinite) family of geometric objects and a set of red points in are given a prior, and blue points from arrives one after another. Upon the arrival of a blue point, the online algorithm must make an irreversible decision to cover it with objects from that do not cover any points of . The objective of the problem is to place a minimum number of objects. When consists of axis-parallel unit squares in , we prove that the competitive ratio of any deterministic online algorithm is , and also propose an -competitive deterministic algorithm for the problem.
期刊介绍:
Computational Geometry is a forum for research in theoretical and applied aspects of computational geometry. The journal publishes fundamental research in all areas of the subject, as well as disseminating information on the applications, techniques, and use of computational geometry. Computational Geometry publishes articles on the design and analysis of geometric algorithms. All aspects of computational geometry are covered, including the numerical, graph theoretical and combinatorial aspects. Also welcomed are computational geometry solutions to fundamental problems arising in computer graphics, pattern recognition, robotics, image processing, CAD-CAM, VLSI design and geographical information systems.
Computational Geometry features a special section containing open problems and concise reports on implementations of computational geometry tools.