An algorithm to find agreement subtrees

Given two binary trees, a largest subtree contained in both of the original trees that has been obtained by pruning vertices is called an agreement subtree. An exact algorithm for finding an agreement subtree is presented.Research of F.R.M. supported by grant number N00014-89-J-1643 from the Office of Naval Research. The authors would like to thank the referees, the Editor, and William H. E. Day for many valuable suggestions.