Wei_Dai comments on indexical uncertainty and the Axiom of Independence - Less Wrong

9 Post author: Wei_Dai 07 June 2009 09:18AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (70)

You are viewing a single comment's thread. Show more comments above.

Comment author: Wei_Dai 09 June 2009 01:14:25AM 3 points [-]

Are you familiar with Cooperative Game Theory? I'm just learning it now, but it sounds very similar to what you're talking about, and maybe you can reused some of its theory and math. (For some reason I've only paid attention to non-cooperative game theory until recently.) Here's a quote from page 356 of "Handbook of Game Theory with Economic Applications, Vol 1":

Of all solution concepts of cooperative games, the core is probably the easiest to understand. It is the set of all feasible outcomes (payoffs) that no player (participant) or group of participants (coalition) can improve upon by acting for themselves.

Comment author: Vladimir_Nesov 10 June 2009 04:37:08PM *  2 points [-]

I couldn't find anything that "clicked" with cooperation in PD. Above, I wasn't talking about a kind of Nash equilibrium protected from coalition deviations. The correlated strategy needs to be a Pareto improvement over possible coalition strategies run by subsets of the agents, but it doesn't need to be stable in any sense. It can be strictly dominated, for example, by either individual or coalition deviations.

Comment author: Wei_Dai 10 June 2009 06:08:30PM 7 points [-]

A core in Cooperative Game Theory doesn't have to be a Nash equilibrium. Take a PD game with payoffs (2,2) (-1,3) (3,-1) (0,0). In Cooperative Game Theory, (-1,3) and (3,-1) are not considered improvements that a player can make over (2,2) by acting for himself. Maybe one way to think about it is that there is an agreement phase, and an action phase, and the core is the set of agreements that no subset of players can improve upon by publicly going off (and forming their own agreement) during the agreement phase. Once an agreement is reached, there is no deviation allowed in the action phase.

Again, I'm just learning Cooperative Game Theory, but that's my understanding and it seems to correspond exactly to your concept.

Comment author: Vladimir_Nesov 10 June 2009 06:15:59PM 2 points [-]

Sounds interesting, thank you.