The subtree center of a tree
A method to determine the least central subtree of a tree is given. The structure of the trees having a single point as a least central subtree is described, and the relation of a least central subtree of a tree to the centroid as well as to the center of that tree is given. (C) 1999 John Wiley & Sons, Inc.
center of a tree central subtrees of a tree centroid of a tree joinsemilattice of subtrees of a tree