On the approximation of largest common subtrees and largest common point sets

Abstract

This paper considers the approximability of the largest common subtree and the largest common subgraph problems, which have applications in molecular biology. It is shown that approximating the problems within a factor of nε is NP-complete, while a general search algorithm which approximates both problems within a factor of O(n/log n) is presented. Moreover, several variants of the largest common subtree problem are studied.