An approximation algorithm for bounded degree closest phylogenetic 2nd root problem

Abstract

The degree Δ-closest phylogenetic 2nd root problem (ΔCPR2) is an NP-hard problem concerning phylogenetic tree reconstruction from a graph representing the similarities of the species concerned. Here we present an approximation algorithm for this problem for any fixed Δ > 3. When |V| > 3Δ − 1, our algorithm yields an approximation ratio of max((Δ−2)/α, 2), where α > 1 is a constant whose value depends on the values of |V| and Δ.