2026-08-25T17:34:07Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:27229 2026-08-25T13:18:18Z ddc:004 open_access

An Approximation Algorithm for 2-Vertex-Connectivity via Cycle-Restricted 2-Edge-Covers Kobayashi, Yusuke Noguchi, Takashi approximation algorithm survivable network design minimum 2-vertex-connected spanning subgraph triangle-free 2-matching In the 2-Vertex-Connected Spanning Subgraph problem (2-VCSS), we are given an undirected graph G, and the objective is to find a 2-vertex-connected spanning subgraph S of G with the minimum number of edges. In the context of survivable network design, 2-VCSS is one of the most fundamental and well-studied problems. There has been active research on improving the approximation ratio of algorithms, and the current best ratio is 4/3, achieved by Bosch-Calvo, Grandoni, and Jabal Ameli. In this paper, we improve the approximation ratio to 95/72+ε (< 1.32). The key idea in our algorithm is to introduce a 2-edge-cover without certain cycle components, and use it as an initial solution. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Yusuke Kobayashi and Takashi Noguchi 2026 Is Part Of LIPIcs, Volume 388, 34th Annual European Symposium on Algorithms (ESA 2026) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ESA.2026.93 urn:nbn:de:0030-drops-272293 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.93 eng https://creativecommons.org/licenses/by/4.0/legalcode