A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, T 1 , T 2 , . . . , T k where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNIwalks that visit all trees in a subtree-prune-andregraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, T , on n leaves, the shortest walk takes Θ(n 2 ) additional steps more than the number of trees in the SPR neighborhood.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.