On the performance of mildly greedy players in cut games

We continue the study of the performance of mildly greedy players in cut games initiated by Christodoulou et al. (Theoret Comput Sci 438:13–27, 2012), where a mildly greedy player is a selfish agent who is willing to deviate from a certain strategy profile only if her payoff improves by a factor of more than \(1+\epsilon \), for some given \(\epsilon \ge 0\). Hence, in presence of mildly greedy players, the classical concepts of pure Nash equilibria and best-responses generalize to those of \((1+\epsilon )\)-approximate pure Nash equilibria and \((1+\epsilon )\)-approximate best-responses, respectively. We first show that the \(\epsilon \)-approximate price of anarchy, that is the price of anarchy of \((1+\epsilon )\)-approximate pure Nash equilibria, is at least \(\frac{1}{2+\epsilon }\) and that this bound is tight for any \(\epsilon \ge 0\). Then, we evaluate the approximation ratio of the solutions achieved after a \((1+\epsilon )\)-approximate one-round walk starting from any initial strategy profile, where a \((1+\epsilon )\)-approximate one-round walk is a sequence of \((1+\epsilon )\)-approximate best-responses, one for each player. We improve the currently known lower bound on this ratio from \(\min \left\{ \frac{1}{4+2\epsilon },\frac{\epsilon }{4+2\epsilon }\right\} \) up to \(\min \left\{ \frac{1}{2+\epsilon },\frac{2\epsilon }{(1+\epsilon )(2+\epsilon )}\right\} \) and show that this is again tight for any \(\epsilon \ge 0\). An interesting and quite surprising consequence of our results is that the worst-case performance guarantee of the very simple solutions generated after a \((1+\epsilon )\)-approximate one-round walk is the same as that of \((1+\epsilon )\)-approximate pure Nash equilibria when \(\epsilon \ge 1\) and of that of subgame perfect equilibria (i.e., Nash equilibria for greedy players with farsighted, rather than myopic, rationality) when \(\epsilon =1\).     

A note on the asymptotic distribution of a Perron-type innovational outlier unit root test with a break

This note provides the asymptotic distribution of a Perron-type innovational outlier unit root test developed by Popp (J Stat Comput Sim 78:1145–1161, 2008) in case of a shift in the intercept for non-trending data. In Popp (J Stat Comput Sim 78:1145–1161, 2008), only critical values for finite samples based on Monte Carlo techniques are tabulated. Using similar arguments as in Zivot and Andrews (J Bus Econ Stat 10:251–270, 1992), weak convergence is shown for the test statistics.     

The origins of the public debt of Italy: Geographically dispersed interests?

In this paper we reconstruct the macro regional government deficits of Italy and find that the aggregate deficit resulting from our estimates captures quite well the entire dynamics of the Italian national public deficit. This new data set shows that the ultimate cause of the accumulation of public debt of Italy lies in the extraordinary fiscal imbalance of the Southern regions. The new data allow us to test empirically a simple Common Pool model, augmented by a variable measuring the political influence of each macro region in the Government, to verify the existence of a geographically dispersed interests issue for the Italian case. Our measure of political influence turns out to significantly explain the regions’ deficits also when controlling for population and income gaps. In addition, using a J-test approach, we find that including the predictions of the Common Pool–Pork Barrel regional model into a general model of the Italian national deficit turns out to greatly increase its explanatory power. The results call for deep institutional reforms of the fiscal decentralization so far implemented in Italy.     

Gender-related Effect of Cultural Participation in Psychological Well-being: Indications from the Well-being Project in the Municipality of Milan

Gender differences have been observed in the way males and females process cognitive stimuli coming from exposure to works of art and participation in leisure activities. For this reason, we designed a project to assess this issue, with a cross-sectional study in Milan, on a sample of the population consisting in 1,000 inhabitants. Our objective was to assess how cultural participation affects subjective well-being, measured with the Psychological General Well-being Scale, which gives a global index of psychological well-being ranging from 0 (lowest level of well-being) to 110 (highest level of well-being). The survey was conducted with the assistance of Doxa, an Italian pollster company, through telephone interviews, according to the Computer Aided Telephone Interview system. A significant statistical difference in variable distribution between the two genders was found for civil status (more males resulted as being single and more women widowed), income (higher income in males), cultural participation (higher in males) and psychological well-being (higher in males). As expected, state of health has the maximum impact on the level of psychological well-being. The increase in the number of concomitant diseases is in fact linearly associated with a progressive increase in psychological distress with average scores of around 60 (very low level of well-being), in the presence of 5 or more concomitant diseases, in both males and females. The impact profile of nine major determinants on subjective well-being resulted to be clearly different in the two genders. Health status dominates in both, but its impact is higher in females than in males. The obtained results remained substantially unchanged also when the two gender groups were matched according to civil status and income level distribution. Leisure activities play an important role in females (second place after health status), while in males they result as being less important (fourth place after health status, civil status and occupation). Education is quite important for females (third place), while it is given the least importance in males. This different profile probably reflects different social and environmental influences on the two genders. The social and psychological implications of these findings are discussed.     

A Mixed Approach for Data Fusion of HBS and SILC

Social Indicators Research - This paper presents an effective procedure for matching data from the Italian Household Budget Survey (HBS) and the Survey on Income and Living Conditions (SILC),...     

RATIONAL HEURISTICS? EXPECTATIONS AND BEHAVIORS IN EVOLVING ECONOMIES WITH HETEROGENEOUS INTERACTING AGENTS

We analyze the individual and macroeconomic impacts of heterogeneous expectations and action rules within an agent-based model populated by heterogeneous, interacting firms. Agents have to cope with a complex evolving economy characterized by deep uncertainty resulting from technical change, imperfect information, coordination hurdles, and structural breaks. In these circumstances, we find that neither individual nor macroeconomic dynamics improve when agents replace myopic expectations with less naïve learning rules. Our results suggest that fast and frugal robust heuristics may not be a second-best option but rather “rational” responses in complex and changing macroeconomic environments. (JEL C63, D8, E32, E6, O4)     

Decentralization and growth: Do informal institutions and rule of law matter?

We develop a model of the interactions among decentralization, informal institutions and the rule of law. The model sheds light on the ambiguous empirical results reported in the literature regarding the growth effects of the policy of devolving fiscal responsibility to local governments. We find that the distribution of civicness within a country determines the magnitude of the effects of decentralization on its regional convergence, as well as whether decentralization fosters or dampens the country’s national growth. We perform a series of simulated “reforms” using Monte Carlo methods parameterized using OECD countries data set. We then test our findings using a panel data set of 23 OECD countries covering the period 1975–2010. We find that the short and the long run growth effect of decentralization policy depends on the size of the policy reform and can range from extremely negative to positive depending on the rule of law, the level of social capital and its regional dispersion, in line with the model predictions.     

COVID: Using the DAN Model with Couples to Increase Family Resilience

The COVID‐19 pandemic has massively impacted our society, affecting both wider systems and smaller ones alike. Families across the world have had to adapt to a new style of living, dominated by uncertainty, which is testing their resilience. Within this context, we have asked ourselves, as systemic therapists, what can be done to provide support and a sense of understanding to families. In this article, it is argued that therapeutic tools taken from a manualised intervention to promote resilience in couples can provide valuable help to families who are struggling in this difficult time. This intervention, developed at the Iscra Institute in Modena, Italy, is called Digital, Analogic, and Narrative (DAN). The tools used in the DAN model are described in this paper and their application in practice is illustrated through a case study.     

Combining Linear and Non-Linear Objectives in Spanning Tree Problems

A classical approach to multicriteria problems asks for the optimization of a suitable linear combination of the objectives. In this work we address such problems when one of the objectives is the linear function, the other is a non-linear one and we seek for a spanning tree of a given graph which optimizes the combination of the two functions. We consider both maximization and minimization problems and present the complexity status of 56 such problems, giving, whenever possible, polynomial solution algorithms.