A note on generically stable measures and fsg groups

We prove that if \mu is a generically stable stable measure in a first order theory with NIP and mu(\phi(x,b)) = 0 for all b, then \mu^{(n)}(\exists y(\phi(x_1,y)\wedge ... \wedge \phi(x_n,y))) = 0. We deduce that if G is an fsg grooup then a definable subset X of G is generic just if every translate of X does not fork over \emptyset.Comment: 8 page

Distal and non-distal NIP theories

We study one way in which stable phenomena can exist in an NIP theory. We start by defining a notion of 'pure instability' that we call 'distality' in which no such phenomenon occurs. O-minimal theories and the p-adics for example are distal. Next, we try to understand what happens when distality fails. Given a type p over a sufficiently saturated model, we extract, in some sense, the stable part of p and define a notion of stable-independence which is implied by non-forking and has bounded weight. As an application, we show that the expansion of a model by traces of externally definable sets from some adequate indiscernible sequence eliminates quantifiers

Finding generically stable measures

We discuss two constructions for obtaining generically stable Keisler measures in an NIP theory. First, we show how to symmetrize an arbitrary invariant measure to obtain a generically stable one from it. Next, we show that suitable sigma-additive probability measures give rise to generically stable measures. Also included is a proof that generically stable measures over o-minimal theories and the p-adics are smooth

Inequality, Well-being and Institutions in Latin America and the Caribbean

This paper focuses on the role of “institutions” in the fight against poverty and inequality. Our view of institutions encompasses formal rules designed by polity (including those in the legal and economics sphere such as rules of property rights, contracts and liabilities) as well as informal rules (usually labelled social capital) that have emerged over the history of one’s civilisation. The inclusion of health, nutrition, and literacy indicators in defining well-being (or, non-income poverty à la capability approach of Amartya Sen) allows a rich discussion of policy interventions. While both orientations as to the concepts of poverty, inequality and institutions are expounded on a priori reasoning, empirical analysis with LAC data prove rewarding. Quality of institutions (measured by a composite variable called institutional capital, IC) turns out to be a key factor explaining well-being. Further where the level of income is also important to the explanation, the quantitative role of the institutional factor dominates that of the income variable. Within IC, political stability (or lack of violence) appeared to provide the more precise estimates in every case. Consequently we argue that the foremost policy interventions ought to be in the areas of building both adequate formal institutions, as well as creating an enabling environment for the informal institutions (such as social capital) to flourish and find their own roots. The principal focus of the policy debate must centre on the mutual interaction of market as well as non-market institutions in reducing poverty broadly speaking

Dependence on External Finance by Manufacturing Sector: Examining the Measure and its Properties

Rajan & Zingales (1998) use U.S. Compustat firm data for the 1980s to obtain measures of manufacturing sectors’ Dependence on External Finance (DEF). They take any differences in these measures to be structural/technological and thus applicable to other countries. Their joint assumptions about how to obtain representative values of DEF by sector and about why these values differ between sectors have been used widely to show that sectors benefit unequally from a country’s level of financial development. However, the assumptions as such have not been examined. The present study, conducted with cyclically adjusted annual DEF measures, attempts to do so using U.S. industry data for 1977-1997 aggregated by sector. The key findings are that structural/ technological variables have low explanatory power for DEF and that the DEF figures calculated from micro data do not correspond closely to what is obtained from aggregate data. Hence assumptions crucial for RZ's argumentation have not been validated.Growth and finance, financial development, industry structure

Model Theory: Around Valued Fields and Dependent Theories

The general topic of the meeting was “Valued fields and related structures”. It included both applications of model theory, as well as so-called “pure” model theory: the classification of first order structures using new techniques extending those developed in stable theories