Far-sighted equilibria in 2 × 2, non-cooperative,repeated games

Consider a two-person simultaneous-move game in strategic form. Suppose this game is played over and over at discrete points in time. Suppose, furthermore, that communication is not possible, but nevertheless we observe some regularity in the sequence of outcomes. The aim of this paper is to provide an explanation for the question why such regularity might persist for many (i.e., infinite) periods.Each player, when contemplating a deviation, considers a sequential-move game, roughly speaking of the following form: if I change my strategy this period, then in the next my opponent will take his strategy b and afterwards I can switch to my strategy a, but then I am worse off since at that outcome my opponent has no incentive to change anymore, whatever I do. Theoretically, however, there is no end to such reaction chains. In case that deviating by some player gives him less utility in the long run than before deviation, we say that the original regular sequence of outcomes is far-sighted stable for that player. It is a far-sighted equilibrium if it is far-sighted stable for both players.     

Age difference asymmetry and a two-sex perspective

The paper shows that (a) the age difference between spouses can be and has been different for men and women; (b) male and female age differences can exhibit different trends; (c) the discrepancy is due to remarriage; (d) the age difference fluctuates substantially through time; (e) trends in the age difference are not readily interpretable as reflecting change in the relative status of the sexes; and (f) that trends in the age difference may be linked to marriage market conditions. The paper argues that marriage and fertility data for both men and women are increasingly necessary because of rises in marital breakdown and the associated divergence of the experience of men and women.Cet article montre que (a) les différences d'âge entre époux peuvent être et ont été dissemblables pour les hommes et les femmes; (b) les différences d'âge masculines et féminines peuvent présenter des tendances différentes; (c) la divergence est due aux remariages; (d) les différences d'âge varient de façon importante au cours du temps; (e) les tendances dans les différences d'âge ne sont pas simplement interprétables en termes de changements dans le statut relatif des sexes; et (f) les tendances dans les différences d'âge peuvent être reliées aux conditions du marché matrimonial. L'article montre que les données sur le mariage et la fécondité à la fois des hommes et des femmes, sont de plus en plus nécessaires du fait de l'accroissement des ruptures d'unions et de la divergence des expériences masculines et féminines, qui lui est associée.

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An earlier version of this paper, His and her age gap: asymmetry in the age difference between partners, was a contributed paper to Session F27 of the General Conference of the International Union for the Scientific Study of Population, New Delhi, 20–27 September 1989. A longer version appeared as LS Working Paper 70, issued by City University Social Statistics Research Unit, September 1990.     

The birth of the queen/the modern homosexual: historical explanations revisited

In this paper I review a number of explanations for the emergence of the modern homosexual category in Western (mainly Northwest European) cultures. I suggest there are four different emphases in respect of the social and cultural factors given priority in interpretations of the formation of the homosexual category. Of course, individual studies have often taken into consideration more than one single factor (most notably, Greenberg, 1988; Chauncey, 1994), and the grouping of previous studies that I here suggest only indicates where the focus of a given study is. The social and cultural factors emphasized in these four approaches are: 1) the effects of competitive capitalism on the bourgeois/middle class political economy of sexuality and sexual morals; 2) the rise of expert knowledges, controlling systems, and modern bureaucracies; 3) tensions within gender order and the struggle over new definitions of gender roles; 4) the rise of free wage labour, the proliferation of urban anonymity, and the unfolding of new modes of existence in the life-world of modern pluralist urban society. Finally, the article briefly considers the potential erosion of the homosexual vs. heterosexual divide in the light of the historical background. Almost thirty years have passed since ‘The Homosexual Role’, by Mary McIntosh (1968), the first notable contribution to the historical sociology of homosexuality operating within a social constructionist view of homosexuality. Since then, there have been numerous studies of the formation of the conceptual category and social aggregate of ‘modern homosexual’. Researchers have differed about whether the pedigree of ‘homosexual’ and homosexual identities and subcultures in Western societies can be traced back to the late nineteenth century or to the early eighteenth century, and whether or not some notion of ‘homosexual’ was established in the cultural imagery before the last fifty years or so. It might be fruitful to distinguish between the historically older categories of ‘molly’, ‘queen’, and ‘fairy’ on the one hand, and the more recent ‘homosexual’ on the other hand. It can be argued that the decisive feature of the first-mentioned ‘deviant men’ was their status as gender-crossers (which as a side-effect entailed an interest in homosexual conduct), whereas the modern term homosexual does not necessarily suggest gender-crossing or more generic ‘sexual inversion’(cf. Chauncey, 1994). However, allusions to gay men's purported effeminacy and lesbian women's purported masculinity continue to surface frequently also in contemporary culture. Hence, for the sake of brevity, I here use the term modern homosexual, by which I refer to a notion that there is in some people an inherent sexual desire exclusively for persons of the same sex, and that this so-called sexual orientation is to some degree intertwined with a tendency to gender-crossing conduct. ¹ 1 Historically there has been a mutually re-enforcing dynamics between the forma-tion of the conceptual category and the social aggregate of homosexual(s). Methodological considerations and also certain presumptions about the dynam-ics of culture and society help explain why, until recently, most studies have focused on the trajectory of concepts, identities, and social roles, rather than on the experiential, embodied aspects of the social aggregate of homosexual(s). The idea of sexual inversion predicates that homosexual desire is evidence of a faulty combination of body and soul: there is ‘a female soul in a male body’, or vice versa. On the distinctions between sexual orientation and sexual role see, King, 1984.
     

How Successful are Highly Qualified Return Migrants in the Lithuanian Labour Market?

This article analyses whether the human capital gained abroad helps returning migrants to integrate into the Lithuanian labour market. The analysis focuses on highly qualified migrants, defined narrowly as people with higher education who held qualified jobs when working abroad. The article found that for this group of returnees professional aims were important when taking a decision to return, together with other motives such as family reasons and home‐sickness. Most of the returnees were able to find employment and pursue their careers without major difficulties, although a significant minority signalled an intention to emigrate again. The article examines the key factors that sometimes helped and sometimes hindered integration of the returnees and discusses the role of the public policy.     

On Combining Wavelets Expansion and Sparse Linear Models for Regression on Metabolomic Data and Biomarker Selection

Wavelet thresholding of spectra has to be handled with care when the spectra are the predictors of a regression problem. Indeed, a blind thresholding of the signal followed by a regression method often leads to deteriorated predictions. The scope of this article is to show that sparse regression methods, applied in the wavelet domain, perform an automatic thresholding: the most relevant wavelet coefficients are selected to optimize the prediction of a given target of interest. This approach can be seen as a joint thresholding designed for a predictive purpose. The method is illustrated on a real world problem where metabolomic data are linked to poison ingestion. This example proves the usefulness of wavelet expansion and the good behavior of sparse and regularized methods. A comparison study is performed between the two-steps approach (wavelet thresholding and regression) and the one-step approach (selection of wavelet coefficients with a sparse regression). The comparison includes two types of wavelet bases, various thresholding methods, and various regression methods and is evaluated by calculating prediction performances. Information about the location of the most important features on the spectra was also obtained and used to identify the most relevant metabolites involved in the mice poisoning.     

A Note on Selection and Gender Unemployment Gaps

Previous research has documented the impact of positive selection into employment on the ranking of countries by gender wage gaps. This note focuses on the impact of selection into labor force on cross-country differences in gender unemployment gaps. We construct the Manski bounds for the selection-free gender unemployment gaps in 26 EU countries and show that - without additional assumptions - the observed gender unemployment gaps carry little information about the selection-free gender differences in unemployment. Contrary to the common assumption of positive selection into labor force (similar to positive selection into employment documented in the gender wage gap research), we also point at an example of negative-selection bias. We show that labor force withdrawal of mothers on job-protected family leaves may lead to an overestimation of the selection-free gender unemployment gaps by as much as 1 p.p.     

Multilevel maximum likelihood estimation with application to covariance matrices

The asymptotic variance of the maximum likelihood estimate is proved to decrease when the maximization is restricted to a subspace that contains the true parameter value. Maximum likelihood estimation allows a systematic fitting of covariance models to the sample, which is important in data assimilation. The hierarchical maximum likelihood approach is applied to the spectral diagonal covariance model with different parameterizations of eigenvalue decay, and to the sparse inverse covariance model with specified parameter values on different sets of nonzero entries. It is shown computationally that using smaller sets of parameters can decrease the sampling noise in high dimension substantially.