A recombining tree is a tree in which an up move followed by a down move reaches the same node as the reverse: after steps the share is at one of the values , , instead of . Pricing on it costs operations and memory.
Ejemplos
Example 2.5 (The whiteboard call)
With , , : . After three steps the share is at 133.1, 108.9, 89.1 or 72.9, and the call pays 33.1, 8.9, 0 or 0. Its value is . At the first node the replicating portfolio holds share and a deposit of ; put–call parity holds on the tree, .