We study the problem of allocating a set of indivisible items to agents with supermodular utilities to maximize the Nash social welfare. We show that the problem is NP-hard for any approximation factor.
A new combinatorial game is given. It generalizes both Substraction and Nim. It is proved the computation of Nash equilibrium points in this new game is NP-hard.
We present an analog of O'Neill's Theorem (Theorem 5.2 in [17]) for finite games, which reveals some of the structure of equilibria under payoff perturbations in finite games.
George Christodoulou, Elias Koutsoupias, Annamaria Kovacs
Noam Nisan and Amir Ronen conjectured that the best approximation ratio of deterministic truthful mechanisms for makespan-minimization for $n$ unrelated machines is $n$. This work validates the conjecture.
We prove that the {\sf PoA} of {\sf First Price Auctions} is $1 - 1/e^2 \approx 0.8647$, closing the gap between the best known bounds $[0.7430,\, 0.8689]$.
We present a $380$-approximation algorithm for the Nash Social Welfare problem with submodular valuations. Our algorithm builds on and extends a recent constant-factor approximation for Rado valuations.
We study multiplayer turn-based timed games with reachability objectives. In particular, we are interested in the notion of subgame perfect equilibrium (SPE). We prove that deciding the constrained existence of an SPE in this setting is EXPTIME-complete.
This paper shows that the PoA in non-atomic congestion games is H{ö}lder continuous w.r.t. combined disturbance on cost functions and demands. We then apply this result to the convergence analysis of the PoA.
Recently, Dogan, Dogan and Yildiz (2015) presented a new efficiency notion for the random assignment setting called SW (social welfare)-efficiency and characterized it. In this note, we generalize the characterization for the more general domain of randomized social choice.
Highpurity germanium (HPGe) detector and gamma spectrometry analysis system have been used for the determination of gamma activities of radionuclides (131I, 137Cs, 134Cs and 40K) in 90 human urine samples collected from residents in four provinces (Surat Thani, Nakhon Si Thammarat, Songkhla and Trang) in southern region, Thailand. Gamma radioactive standard sources (109Cd, 57Co, 133Ba, 137Cs, 54Mn and 60Co) were used to calibrate the detector and measurement system. Moreover, the well-known reference material 131I in human urine were also used to analyze and determine all of human urine samples. The measuring time of each sample is 10,800 seconds. It was found that, the gamma activities of 131I, 137Cs, 134Cs and 40K in all samples were ranged from 0.35 7.74 Bq/d for 131I, 0.28 7.38 Bq/d for 137Cs, 0.20 9.93 Bq/d for 134Cs and 8.56 274.32 Bq/d for 40K with an average values of 2.40 ± 0.78 Bq/d, 2.41 ± 0.92 Bq/d, 2.66 ± 0.84 Bq/d and 93.50 ± 30.13 Bq/d, respectively. All results showed that no statistically significant correlation with the residential area. Furthermore, the present study data could be used to be a baseline data of gamma activities in human urine of Thai people in the southern Thailand. Moreover, this new database would be not only useful in comparing and assessing an amount of gamma activities inside human body but also monitoring the exposure of radioactivity to Thai people in case of emergency of nuclear accidents around the world.
An overview of different variants of the submodular welfare maximization problem in combinatorial auctions. In particular, I studied the existing algorithmic and game theoretic results for submodular welfare maximization problem and its applications in other areas such as social networks.
Cournot dynamical game is studied on a graph. The stability of the system is studied. Prisoner's dilemma game is used to model natural gas transmission.
The rank of a bimatrix game (A,B) is the rank of the matrix A+B. We give a construction of rank-1 games with exponentially many equilibria, which answers an open problem by Kannan and Theobald (2010).
We show that it is NP-Complete to decide whether a bimatrix game is degenerate and it is Co-NP-Complete to decide whether a bimatrix game is nondegenerate.
An abstraction of normal form games is proposed, called Feasibility/Desirability Games (or FD Games in short). FD Games can be seen from three points of view: as a new presentation of games in which Nash equilibria can be found, as choice models in microeconomics or as a model of evolution in games.
We prove that optimal strategies exist in every perfect-information stochastic game with finitely many states and actions and a tail winning condition.
We describe a new system for the simulation of simultaneous moves between noncolocational players. This has applications in the burgeoning Rock-Paper-Scissors by mail movement.