Counterfactual Regret Minimization
Updated 2026-08-11
INTRODUCTION
English translation pending.
CORE DEFINITION
Counterfactual regret minimization is a family of algorithms for solving sequential games: at each information set it computes the regret, how much better the player would have done by choosing the alternative action, and updates the strategy in proportion to that accumulated regret. Over many iterations the average strategy converges to a Nash equilibrium, which is why it became the standard approach for imperfect-information games where direct equilibrium computation is intractable.
SCAFFOLDING EFFECT
Reduce cognitive load
- Track the regret: record at each decision point how much the missed move would have gained. - Weight the strategy: play actions in proportion to their accumulated regret. - Iterate to equilibrium: average the strategies rather than trusting any single round.
Anchor fast decisions
Regret is a gradient in strategy space, pointing from what was done toward what should have been done. Updating in proportion to it moves the strategy along that gradient, and because each player's update conditions on the other's current play, the joint dynamics converge to a profile where no player's regret points anywhere useful, which is the definition of equilibrium.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- doi.orghttps://doi.org/10.5555/1838206.1838229verified
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