Adversarial Search

Outline

Games vs. search problems

Let’s play!

Game tree (2-player, deterministic, turns)

Example : Game of NIM

Minimax

Minimax algorithm

Properties of minimax

α-β pruning example

α-β pruning example

α-β pruning example

α-β pruning example

α-β pruning example

Properties of α-β

Why is it called α-β?

The α-β algorithm

The α-β algorithm

Resource limits

Evaluation functions

Expected utility value

Cutting off search

Deterministic games in practice

Summary