The Tree Data Model - The Stanford University InfoLab

226 THE TREE DATA MODEL If m1,m2,...,mk is a path in a tree, node m1 is called an ancestor of mk and node mk a descendant of m1.If the path is of length 1 or more, then m1 is called a Proper ancestor proper ancestor of mk and mk a proper descendant of m1.Again, remember that and descendant the case of a path of length 0 is possible, in which case the path lets us conclude

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