pygambit.gambit.MixedBehaviorProfile.beliefs#
- MixedBehaviorProfile.beliefs#
Returns, for each node, the conditional probability that the node is reached, given that its information set is reached, if all players play according to the profile.
The conditioning event is that the information set is reached at least once, so beliefs are normalized by the upper-frontier probability returned by infoset_probs (following [HalPas21]), rather than by the sum of the members’ realization probabilities. For a non-absent-minded information set the two approaches agree. For an absent-minded information set they need not: the beliefs over its members may sum to more than one.
If a node’s information set is reached with zero probability under the profile, the belief is not well-defined and the corresponding entry is None. This is the same reach probability returned by infoset_probs, so a None belief corresponds exactly to infoset_probs being zero there.
See also