In a {{tree} the branching factor of a node refers to the number of branches/children of the node. For the tree as a whole this may be fixed (e.g. a branching factor of 2 for a binary tree) or may vary between nodes (as is often the case in search trees). One may therefore talk about a maximum or average branching factor of a tree. For example, for the first move in Go there are 19x19 possible moves, so the branching factor at the root is 361 (although some are equivalent).
. In a directed graph , that is when the links/arcs between nodes have a direction, one can talk about the forward and backward branching factors. The former is the number of outward links and the latter the numer of inward links.
Used in Chap. 4: pages 40, 41, 45, 54; Chap. 11: page 148; Chap. 15: page 223
Also known as backward branching factor, backward, forward, forward branching factor