•For "nodes" that contain two data items
–there can be either no children or 3
children:
–In this case, the value of the smaller
key at the "node" must be greater than the value of each key in the left
subtree and smaller than the value of each key in the middle subtree.
–The value of the larger key at the
"node" must be greater than the value of each key in the middle subtree
and smaller than the value of each key in the right subtree.