Reputation and commitment in two-person repeated games without discounting

Two-person repeated games with no discounting are considered where there is uncertainty about the type of the players. If there is a possibility that a player is an automaton committed to a particular pure or mixed stage-game action, then this provides a lower bound on the Nash equilibrium payoffs to a normal type of this player. The lower bound is the best available and is robust to the existence of other types. The results are extended to the case of two-sided uncertainty. This work extends Schmidt (1993) who analyzed the restricted class of conflicting interest games

Reputation and perfection in repeated common interest games

We consider a wide class of repeated common interest games perturbed with one-sided incomplete information: one player (the informed player) might be a commitment type playing the Pareto dominant action. As discounting, which is assumed to be symmetric, and the prior probability of the commitment type go to zero, it is shown that the informed player can be held close to her minmax payoff even when perfection is imposed on the equilibrium

Reputation and commitment in two-person repeated games

Game Theory;Repeated Games

Reputation in perturbed repeated games

The paper analyzes reputation effects in perturbed repeated games with discounting. If there is some positive prior probability that one of the players is committed to play the same (pure) action in every period, then this provides a lower bound for her equilibrium playoff in all Nash equilibria. This bound is tight and independent of what other types have positive probability. It is generally lower than Fudenberg and Levine's bound for games with a long-run player facing a sequence of short-run opponents. The bound cannot be improved by considering types playing finitely complicated history-dependent commitment strategies

The strong Atiyah conjecture for right-angled Artin and Coxeter groups

We prove the strong Atiyah conjecture for right-angled Artin groups and right-angled Coxeter groups. More generally, we prove it for groups which are certain finite extensions or elementary amenable extensions of such groups.Comment: Minor change

Evolution of Kenya's Maize Marketing Systems in the Post-liberalization Era

The objectives of this paper are to: (1) identify the pattern of private sector investment in the maize marketing system since the reforms were initiated and evaluate the extent of private sector response to the reforms; (2) assess how maize prices and marketing margins have changed in response to the market reforms; (3) identify market-oriented mechanisms that have evolved in the current environment to reduce vulnerability of farmers, traders and consumers to price and expenditure instability; and (4) identify strategies that the government and private sector could implement to effectively promote the development of the evolving market oriented food systems.Food Security, Food Policy, Kenya, Maize, Crop Production/Industries, Marketing,

Geochronological constraints on the metamorphic sole of the Semail ophiolite in the United Arab Emirates

The Semail ophiolite of Oman and the United Arab Emirates (UAE) provides the best preserved large slice of oceanic lithosphere exposed on the continental crust, and offers unique opportunities to study processes of ocean crust formation, subduction initiation and obduction. Metamorphic rocks exposed in the eastern UAE have traditionally been interpreted as a metamorphic sole to the Semail ophiolite. However, there has been some debate over the possibility that the exposures contain components of older Arabian continental crust. To help answer this question, presented here are new zircon and rutile U-Pb geochronological data from various units of the metamorphic rocks. Zircon was absent in most samples. Those that yielded zircon and rutile provide dominant single age populations that are 95–93 Ma, partially overlapping with the known age of oceanic crust formation (96.5–94.5 Ma), and partially overlapping with cooling ages of the metamorphic rocks (95–90 Ma). The data are interpreted as dating high-grade metamorphism during subduction burial of the sediments into hot mantle lithosphere, and rapid cooling during their subsequent exhumation. A few discordant zircon ages, interpreted as late Neoproterozoic and younger, represent minor detrital input from the continent. No evidence is found in favour of the existence of older Arabian continental crust within the metamorphic rocks of the UAE

Metal Abundance Calibration of the Ca II Triplet Lines in RR Lyrae Stars

The GAIA satellite is likely to observe thousands of RR Lyrae stars within a small spectral window, between 8470A and 8750A, at a resolution of 11,500. In order to derive the metallicity of RR Lyrae stars from Gaia, we have obtained numerous spectra of RR Lyrae stars at a resolution of 35,000 with the Apache Point Observatory 3.5 m echelle spectrograph. We have correlated the Ca II triplet line strengths with metallicity as derived from Fe II abundances, analogous to Preston's (1959) use of the Ca II K line to estimate the metallicity of RR Lyrae stars. The Ca II line at 8498A is the least blended with neighboring Paschen lines and thus provides the best correlation.Comment: Accepted for publication in Astrophysics & Space Scienc

Inflammatory and immune system correlates of rape

The purpose of this study was to evaluate the feasibility of measuring stress hormones and immunity following rape. The long-term goal is to evaluate the predictive value of stress-immune-inflammatory responses to later health outcomes. Fifteen women reporting rape were compared with 16 control participants. Serum stress hormones, proinflammatory cytokines, acute phase proteins, functional assays, and lymphocyte subsets were measured in blood samples. Women reporting rape had higher cytotoxic cells, lower B lymphocyte counts, higher proinflammatory biomarkers, and decreased lymphocyte proliferation compared to the control group. This finding suggests that rape produces activation of the innate immunity and suppression of some aspects of adaptive immunity. If these immune changes persist, they may contribute to the pathophysiology of long-term health sequelae by provoking chronic inflammation and decreased cellular immunocompetence