Game Theory

Information Set

Given what that player has observed, an information set shows the decision vertices available to the player which are undistinguishable to them at the current point in the game.

In a perfect information game, every information set only contains one member.

You can circle, or box, or circle.

Two rules:

  1. Each node can only be part of one information set.
  2. Each node in an information set must have the same branches.

In a game of Perfect Information, players always know what node they are at. Each information set contains exactly one node.

In a game of Imperfect Information, at least one information set contains more than one node.