Thursday, 25 August 2011

Playing with a madman (Baltag at LGS7)

Like all theories, game theory has its own simplifying assumptions. One of these is the rationality of players, that is: a player, like a true homo oeconomicus will maximise its payoff. As a result the outcome of a noncooperative game will be a Nash equilibrium since it consists of best responses to other players' strategies. But then how should we play the game when the opponent is not rational, especially if she has already made irrational choices?

Sunday, 31 July 2011

On the accessibility of the core (Review)

This paper by Yang (2010) belongs to a recent wave of literature that study the core of a cooperative game as a dynamic concept. Sengupta and Sengupta (1996) have shown that from any imputation the core can be accessed by a finite number of blocks. Kóczy (2006) provided an alternative blocking sequence and showed that the number of blocks required is bounded. The present paper relies on the proof of Sengupta and Sengupta by using z-dominance and provides an explicit bound on the length of z-dominance paths: the number of active coalitions, that is, coalitions with a payoff higher than the sum of their members' individual payoffs.

Monday, 25 July 2011

LGS7 - Part I.: Salles on the impossibility of liberalism

I am often annoyed if I miss an interesting conference.  In this post I report on LGS7 – the 7th Conference on Logic Game Theoryand Social Choice, held last week in Bucharest. Of course this post will not help me with missed conferences, but hopefully other game theorists will find them interesting.
There are two types of conferences. The big ones, like the EEA-ESEM meetings, where you can network with a lot of new people, but honestly, with most of them, you are not likely to meet ever again. There are also the small, field conferences, where there is always the risk that you meet all the same people as last year (this can also be nice, too), who give a talk you already know. LGS is the third kind, as it collects people from different disciplines (logicians, game theorists, social choice theorists, but also sociologists, computer scientists) with very specialised interests. As it is organised biannually, it is also unlikely that you will hear an updated version of what you have heard last year.

Thursday, 17 March 2011

Finessing a point: augmenting the core (Review)

The competition between two election candidates is modelled in a policy space, where the voters are represented by their ideal points and the candidates by their position on the policy. A voter will support the candidate whose programme is closer to his ideal point, using Euclidean distance. The candidate supported by at least q voters, where q is the quota, is elected. For simple majority q is simply the smallest integer that is at least half of the number of voters.

Tuesday, 18 January 2011

The class of efficient linear symmetric values for games in partition function form (Review)

The paper studies linear, symmetric and efficient (LSE) solutions or values for games in partition function form. The family of such solutions is rather broad and includes the Shapley value, the Consensus value and the Myerson value just to mention some.

Friday, 14 January 2011

Desperate neighbours

Just follow the arrow(s?)
In some of the recent episodes of Desperate Housewives Paul Young has created a social dilemma: a "bank run" for the neighbours on Wisteria Lane. Read on to see the details of his cunning plan. (Spoiler!)

Thursday, 6 January 2011

Discussion of "Matching with Minimal Priority Rights" by Szilvia Pápai

Assigning a seat
Two-sided matching problems with rather different two sides are fairly common. Of course I do not mean the man-woman dichotomy, but rather schools and pupils and offices and staff members. Unlike most authors in the matching literature, Pápai uses this extra info to design a class of matching rules where the two sides are not acting the same. Here are my summary and comments as presented at the annual congress of the Hungarian Society for Economics, 20-21 December, 2011, Budapest.

Tuesday, 4 January 2011

The good, the bad, and the ugly - Media law in Hungary

Hungary has recently passed a new law regulating the media. I obviously cannot read all the international media, but apparently it is full of criticism/concern/outrage. Unfortunately the edge of that criticism is often taken away by the fact that the cited politician is a radical leftist minister of a small country, the leader of the European Socialists or perhaps a Budapest based news reporter who is known to be anti-Orbán irrespective of what he does, whether he is in or out of power. I haven't really heard of criticisms of Mr Orbán's Christian-Democrat pals - but then again, you do not expect that, really. So I took some time and read a whole bunch of news items, blog entries an the like on the new law to form my own opinion. My conclusion: most criticism is related to the fact that Mr Orbán's cabinet has an overwhelming majority in the Parliament and therefore in all related bodies, too.