,
Eun Jung Kim
,
Euiwoong Lee
Creative Commons Attribution 3.0 Unported license
For a family of graphs ℱ, Weighted ℱ-Deletion is the problem for which the input is a vertex weighted graph G = (V, E) and the goal is to delete S ⊆ V with minimum weight such that G⧵S ∈ ℱ. Designing a constant-factor approximation algorithm for large subclasses of perfect graphs has been an interesting research direction. Block graphs, 3-leaf power graphs, and interval graphs are known to admit constant-factor approximation algorithms, but the question is open for chordal graphs and distance-hereditary graphs. In this paper, we add one more class to this list by presenting a constant-factor approximation algorithm when ℱ is the intersection of chordal graphs and distance-hereditary graphs. They are known as ptolemaic graphs and form a superset of both block graphs and 3-leaf power graphs above. Our proof presents new properties and algorithmic results on inter-clique digraphs as well as an approximation algorithm for a variant of Feedback Vertex Set that exploits this relationship (named Feedback Vertex Set with Precedence Constraints), each of which may be of independent interest.
@InProceedings{ahn_et_al:LIPIcs.ISAAC.2020.62,
author = {Ahn, Jungho and Kim, Eun Jung and Lee, Euiwoong},
title = {{Towards Constant-Factor Approximation for Chordal / Distance-Hereditary Vertex Deletion}},
booktitle = {31st International Symposium on Algorithms and Computation (ISAAC 2020)},
pages = {62:1--62:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-173-3},
ISSN = {1868-8969},
year = {2020},
volume = {181},
editor = {Cao, Yixin and Cheng, Siu-Wing and Li, Minming},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2020.62},
URN = {urn:nbn:de:0030-drops-134063},
doi = {10.4230/LIPIcs.ISAAC.2020.62},
annote = {Keywords: ptolemaic, approximation algorithm, linear programming, feedback vertex set}
}