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dc.contributor.authorNarayan, Vishnu Verambudi
dc.date.accessioned2017-04-27 13:59:53 (GMT)
dc.date.available2017-04-27 13:59:53 (GMT)
dc.date.issued2017-04-27
dc.date.submitted2017-04-25
dc.identifier.urihttp://hdl.handle.net/10012/11768
dc.description.abstractWe study the unweighted 2-edge-connected and 2-vertex-connected spanning subgraph problems. A graph is 2-edge-connected if it is connected on removal of an edge, and it is 2-vertex-connected if it is connected on removal of a vertex. The problem of finding a minimum-size 2-edge-connected (or 2-vertex-connected) spanning subgraph of a given graph is NP-hard. We present a 4/3-approximation algorithm for unweighted 2ECSS on 3-vertex-connected input graphs, which matches the best known approximation ratio due to Sebő and Vygen for the general unweighted 2ECSS problem, but our analysis is with respect to the D2 lower bound. We also give a 17/12-approximation algorithm for unweighted 2VCSS on graphs of minimum degree at least 3, which is lower than the best known ratios of 3/2 by Garg, Santosh and Singla and 10/7 by Heeger and Vygen for the general unweighted 2VCSS problem. These algorithms are accompanied by new theorems about the known lower bounds.en
dc.language.isoenen
dc.publisherUniversity of Waterlooen
dc.subjectCombinatorics and Optimizationen
dc.subjectApproximation Algorithmsen
dc.subjectGraph Connectivityen
dc.titleApproximating Minimum-Size 2-Edge-Connected and 2-Vertex-Connected Spanning Subgraphsen
dc.typeMaster Thesisen
dc.pendingfalse
uws-etd.degree.departmentCombinatorics and Optimizationen
uws-etd.degree.disciplineCombinatorics and Optimizationen
uws-etd.degree.grantorUniversity of Waterlooen
uws-etd.degreeMaster of Mathematicsen
uws.contributor.advisorCheriyan, Joseph
uws.contributor.affiliation1Faculty of Mathematicsen
uws.published.cityWaterlooen
uws.published.countryCanadaen
uws.published.provinceOntarioen
uws.typeOfResourceTexten
uws.peerReviewStatusUnrevieweden
uws.scholarLevelGraduateen


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