1. In a postorder traversal, the binary tree is traversed as follows:
a. Traverse the left subtree.
b. Traverse the right subtree.
c. Visit the node.
2. A binary search tree T is either empty or:
i. T has a special node called the root node;
ii. T has two sets of nodes, LT and RT, called the left subtree and the right subtree of T, respectively;
iii. The key in the root node is larger than every key in the left subtree and smaller than every key in the right subtree; and
iv. LT and RT are binary search trees.
3. To delete a node from a binary search tree that has both left and right nonempty subtrees, first its immediate predecessor is located, then the predecessor’s info is copied into the node, and finally the predecessor is deleted.