Seven rules to avoid the tragedy of the commons

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Cooperation among self-interested players in a social dilemma is fragile and easily interrupted by mistakes. In this work, we study the repeated <I>n</I>-person public-goods game and search for a strategy that forms a cooperative Nash equilibrium in the presence of implementation error with a guarantee that the resulting payoff will be no less than any of the co-players’. By enumerating strategic possibilities for n = 3 , we show that such a strategy indeed exists when its memory length <I>m</I> equals three. It means that a deterministic strategy can be publicly employed to stabilize cooperation against error with avoiding the risk of being exploited. We furthermore show that, for general <I>n</I>-person public-goods game, <I>m</I> ≥ <I>n</I> is necessary to satisfy the above criteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose strategies to stabilize cooperation in the iterated public-goods game. </LI> <LI> They can recover cooperation in the presence of implementation error. </LI> <LI> They are secured from repeated exploitation. </LI> <LI> They suppress neutral drift to unconditional cooperation. </LI> <LI> For an <I>n</I>-person case, the memory length of such strategies cannot be less than <I>n</I>. </LI> </UL> </P>