Game theory

Potential Games

Games where all unilateral payoff changes are captured by a single real-valued function.

Ask the Game theory assistant 1 min read · Updated September 9, 2026

Definition

GG is an exact potential game if there exists Φ:S→R\Phi:S\to\mathbb{R} with ui(si′,s−i)−ui(si,s−i)=Φ(si′,s−i)−Φ(si,s−i)u_i(s_i',s_{-i})-u_i(s_i,s_{-i})=\Phi(s_i',s_{-i})-\Phi(s_i,s_{-i}) for all i,si,si′,s−ii,s_i,s_i',s_{-i}.

Ordinal, weighted, and generalized-ordinal potentials relax the equality requirement.

Intuition

Players jointly hill-climb a common function — best-response dynamics always converge.

This gives potential games strong computational and learnability properties.

Worked example

Congestion games are exact potential games with Φ(s)=∑e∑k=1fe(s)ce(k)\Phi(s)=\sum_e\sum_{k=1}^{f_e(s)}c_e(k) (Rosenthal 1973).

Coordination games on graphs are (weighted) potential games.

The math

Monderer-Shapley (1996): every finite potential game has a pure Nash equilibrium — the maximizer of Φ\Phi.

Better-response and fictitious-play dynamics converge to Nash in potential games.

Where it is used

Distributed sensor networks use potential-game formulations to coordinate channel selection: each sensor's local decision to switch channels corresponds to climbing the potential function, guaranteeing convergence to interference-minimizing configurations.

Bridge to convex optimization via Φ\Phi.

More in Game theory

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