Alphabetic Binary Trees

If a given sequence of nodes is used to build a binary tree, the tree is called alphabetic iff the leaf nodes of the tree obey the order of the initial sequence from left to right. An alphabetic key constraint does not imply a binary search mechanism. Thus the internal nodes of the alphabetic tree do not have to provide information for locating the leaf nodes of the tree.

An alphabetic binary search tree on the other hand implies that the initial sequence of nodes will appear with preserved alphabetic order as leaf nodes of tree but the internal nodes of the tree will also contain the required information so that a binary search procedure can be used to locate an arbitrary node from the initial sequence in the crown of the tree.