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arXiv · 1809.08437

A 2-Approximation Algorithm for Feedback Vertex Set in Tournaments

Daniel Lokshtanov·Pranabendu Misra·Joydeep Mukherjee·Geevarghese Philip·Fahad Panolan·Saket Saurabh
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Abstract

A {\em tournament} is a directed graph $T$ such that every pair of vertices is connected by an arc. A {\em feedback vertex set} is a set $S$ of vertices in $T$ such that $T - S$ is acyclic. We consider the {\sc Feedback Vertex Set} problem in tournaments. Here the input is a tournament $T$ and a weight function $w : V(T) \rightarrow \mathbb{N}$ and the task is to find a feedback vertex set $S$ in $T$ minimizing $w(S) = \sum_{v \in S} w(v)$. We give the first polynomial time factor $2$ approximation algorithm for this problem. Assuming the Unique Games conjecture, this is the best possible approximation ratio achievable in polynomial time.

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Daniel Lokshtanov, Pranabendu Misra, Joydeep Mukherjee, Geevarghese Philip, Fahad Panolan, Saket Saurabh. 2018-09-22. A 2-Approximation Algorithm for Feedback Vertex Set in Tournaments. https://arxiv.org/abs/1809.08437

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