Next: Belief revisionFigure 4.2 describes the game tree that is generated by the planner from the plan library. At the root node, the first agent takes grounding initiative in choosing a non-risky strategy, or declines the initiative by taking a risky strategy. The non-risky strategy leads to the always successful outcome described by the lower branch. The risky strategy leads to a choice by the second agent about whether to clarify the first agent's intention. If it does clarify, there are two possible responses from the first agent, leading to the conclusion of the dialogue. If it does not clarify, it must choose between responses, each of which risks failure. Game tree for example 1