Approximate well-supported Nash equilibria in symmetric bimatrix games

The $\varepsilon$-well-supported Nash equilibrium is a strong notion of approximation of a Nash equilibrium, where no player has an incentive greater than $\varepsilon$ to deviate from any of the pure strategies that she uses in her mixed strategy. The smallest constant $\varepsilon$ currently known for which there is a polynomial-time algorithm that computes an $\varepsilon$-well-supported Nash equilibrium in bimatrix games is slightly below $2/3$. In this paper we study this problem for symmetric bimatrix games and we provide a polynomial-time algorithm that gives a $(1/2+\delta)$-well-supported Nash equilibrium, for an arbitrarily small positive constant $\delta$

A Direct Reduction from k-Player to 2-Player Approximate Nash Equilibrium

We present a direct reduction from k-player games to 2-player games that preserves approximate Nash equilibrium. Previously, the computational equivalence of computing approximate Nash equilibrium in k-player and 2-player games was established via an indirect reduction. This included a sequence of works defining the complexity class PPAD, identifying complete problems for this class, showing that computing approximate Nash equilibrium for k-player games is in PPAD, and reducing a PPAD-complete problem to computing approximate Nash equilibrium for 2-player games. Our direct reduction makes no use of the concept of PPAD, thus eliminating some of the difficulties involved in following the known indirect reduction.Comment: 21 page

Local search: A guide for the information retrieval practitioner

There are a number of combinatorial optimisation problems in information retrieval in which the use of local search methods are worthwhile. The purpose of this paper is to show how local search can be used to solve some well known tasks in information retrieval (IR), how previous research in the field is piecemeal, bereft of a structure and methodologically flawed, and to suggest more rigorous ways of applying local search methods to solve IR problems. We provide a query based taxonomy for analysing the use of local search in IR tasks and an overview of issues such as fitness functions, statistical significance and test collections when conducting experiments on combinatorial optimisation problems. The paper gives a guide on the pitfalls and problems for IR practitioners who wish to use local search to solve their research issues, and gives practical advice on the use of such methods. The query based taxonomy is a novel structure which can be used by the IR practitioner in order to examine the use of local search in IR

ICGA Journal 24(2): special issue on Ken Thompson

This special issue of the ICGA_J focuses on Ken Thompson on the occasion of his retirement from Bell Labs in December 2000. The contents touch on Unix and cover ken's contribution to computer games, computer chess and 'ICCA', the International Computer Chess Association

Harmonia Evangelistarum Emedullata, Hoc Est, Observationes Sacrae, In Quatuor Evangelistas : In quibus Sensus literalis breviter & succincte explicatur, difficiliora cum primis loca illustrantur & a falsis interpretamentis vindicantur

Editae studio & opera Christophori Althoferi ...Anderer Druck als VD17 39:128458R, da abweichendes Impressum vorhanden istVorlageform des Erscheinungsvermerks: Sumptibus Georgii Friderici Zigleri, Bibliop. Culmb. Ienae Excudebat Georgius Sengenwaldus. Anno M.DC.LIII

Australian native plants : a plant for every purpose

Australian native plants : a plant for every purpos

BrisBAMN!? Bringing the streets into the museum

Brisbane is the narcotic of Queensland's extreme difference. It is a state of exceptional boredom and brutality. This article discusses an exhibition (Taking it to the streets) that explores a period in Brisbane's history when young people sought to change the world through political activities

Nocturnal Experiments on Worthless Bodies : Gothic Poetics in Friedrich Engels’ Ethnography of Night Work

Friedrich Engels’ The Condition of the Working-Class in England (1845) features a pioneering multisensory ethnography of the factory system. His critique of the industrial revolutionization of light for 24/7 production adapted a contemporaneous Gothic imaginary of the night. In The Philosophy of Manufactures (1835), Andrew Ure repudiated a physician who condemned night-work’s effects on factory children – “if light is excluded from tadpoles, they never become frogs” – by counter-claiming: “the number and brilliancy of the gas-lights in a cotton-mill” militated against child-labourers lingering “in the tadpole state.” Dispelling Ure’s thinking as blinding fantasy, Engels revealed “the vampire property-holding class” penetrating night-workers with “very powerful light … most injurious to the sight.” He brilliantly anticipated Karl Marx’s demonstration in Capital (1867) that industrial revolutionism, involving capital’s rapid take-up of new lighting technologies, occurred “at the expense of the workpeople. Experimenta in corpore vili, like those of anatomists on frogs, were formally made.”La condition de la classe ouvrière en Angleterre (1845) de Friedrich Engels constitue une ethnographie multisensorielle pionnière du système de l’usine. Sa critique de la révolution industrielle de la lumière pour une production 24/7 a traduit un imaginaire gothique contemporain de la nuit. Dans The Philosophy of Manufactures (1835), Andrew Ure répudie un médecin qui condamnait les effets du travail de nuit sur les enfants des usines – « si la lumière est niée aux têtards, ils ne deviennent jamais des grenouilles » – en rétorquant que « le nombre et l’éclat des lampes à gaz dans une filature de coton » allaient à l’encontre des enfants qui travaillaient « à l’état de têtard ». Évacuant la pensée d’Ure comme un fantasme aveuglant, Engels a révélé « le vampirisme de la classe des propriétaires » transperçant les travailleurs de nuit avec « une lumière très puissante... la plus nuisible à la vue ». Il a brillamment anticipé la démonstration de Karl Marx dans Le Capital (1867), selon laquelle la révolution industrielle, qui implique l’adoption rapide par le capital des nouvelles technologies d’éclairage, s’est produite « aux dépens des travailleurs. C’étaient de véritables expériences in corpore vili, comme celles des vivisecteurs sur les grenouilles »

BrisBAMN!? Bringing the Streets into the Museum

Brisbane is the narcotic of Queensland's extreme difference. It is a state of exceptional boredom and brutality. This article discusses an exhibition (Taking it to the streets) that explores a period in Brisbane's history when young people sought to change the world through political activities