Over the twentieth century advanced economies have seen an economic and social development process which was build upon the consolidation of a strong middle class. Yet, recent decades have seen an increase in wealth and income inequality, reaching levels not seen since before the Second World War. This thesis explore some of the these issues in two parts. The focus of the first part of the thesis is on the role of education and technology in the rise of the middle class. By means of an overlapping generations model with endogenous growth, I study the conditions that enable a society to transit from underdevelopment to development. The model in place reproduces a Kuznets curve, which is deemed an important empirical feature of the history of advanced economies. The second part focuses on the fall of the middle class, by studying the effect of technology and skills in job polarisation - i.e. the fall in employment in middle-skill occupations. The approach is both theoretical and empirical. A sorting model based on tasks is developed and adapted to study polarisation. Central to this model are the distributions of skills that workers have. Thus, a complete chapter is dedicated to characterise these ability distributions, using longitudinal data from the UK for 1991-2008 in an econometric model based on the so-called Mincer equation. The estimated distributions - positive skewed - are used to calibrate the sorting model. Then, this model is used to identify the nature of the technological process affecting the UK economy over the selected period of study. Simple counterfactual exercises shed light on the strong effect of technical progress on both polarisation and inequality. In contrast, the role of change in skills is negligible. The overall conclusion is that the nature of technological change is essential in defining distributional outcomes: whilst technology can enable the rise to a strong middle class, it can also undermine it.

O objetivo desta dissertação é estudar o problema de autovalor de Dirichlet para variedades riemannianas completas. Mais precisamente, pretendemos estudar uma cota por baixo para o -ésimo autovalor de um domínio limitado em uma variedade riemanniana completa. Tal cota é obtida fazendo-se uso de uma fórmula de recorrência de Cheng e Yang e um teorema de Nash. Ademais, pretendemos estudar uma desigualdade universal para os autovalores no espaço hiperbólico. / The goal of this dissertation is to study the Dirichlet eigenvalue problem for a complete riemannian manifold. More accurately, we intend to investigate a lower-bound for the -ℎ eigenvalue on a bounded domain in a complete riemannian manifold. Such a bound is obtained by making use of a recursion formula of Cheng and Yang and Nash’s Theorem. Furthermore, we study a universal inequality for eigenvalues of the Dirichlet eigenvalue problem on a bounded domain in a hyperbolic space (−1).

The standard Keynesian view predicts that equalization of the income distribution leads to an increase in aggregate consumption. We revisit the analysis carried out by the seminal empirical contributions which test such a hypothesis using modern econometric methods and the most comprehensive dataset existing on income distribution measures. Our results indicate that there is no empirical evidence of a negative effect of income inequality on aggregate consumption.

The dissertation investigates the effects of real exchange rate undervaluations upon long-run economic growth and development and focuses on three issues. Rodrik (2008) claims that weak institutions hurt the development of the tradable sector more than that of the nontradable sector and that undervaluation can foster growth by diminishing the distortion created by weak institutions between the two sectors. Using the International Country Risk Guide (ICRG) dataset on four components of institutional quality, Chapter One of my dissertation examines the effects of investment profile, law and order, corruption, and bureaucratic quality upon the relative development of the tradable sector to the nontradable sector, which is measured by the ratio of industry value added to services valued added. On the basis of comparison of the two sectors, the panel evidence of 131 countries indicates that none of the four components mentioned above is positively associated with the relative development of the tradable sector to the nontradable sector. That is, the tradable sector does not suffer disproportionately (compared to the nontradable sector) from institutional weaknesses. Our results cast skepticism upon one of Rodrik's explanations on the growth-promoting effects of real undervaluation because the existence of such a distortion is not supported empirically. Chapter Two concentrates on the effect of real undervaluations on one key aspect of economic development, the income distribution. Based upon the recent availability of an undervaluation index and two databases on Gini coefficients, this study investigates how real undervaluations affect levels and changes in income inequality. The panel evidence of 136 countries indicates that real undervaluations are associated with a decline in levels of income inequality but have no significant association with changes in income inequality. Therefore, the relationship between real undervaluations and levels of income inequality is likely to stem from reverse causality. My main findings may help policymakers who attempt to use an undervaluation policy fully realize that real undervaluations will not hurt the distribution of income. Moreover, I also revisit Rodrik's growth regressions so as to investigate whether or not the same positive association between real undervaluations and economic growth held in Rodrik (2008) reoccurs in my sample. The results are somewhat mixed, depending upon which dataset is employed. Motivated by two distinct characteristics in economic performance of East Asia and Latin America in the past half century, Chapter Three explores the possibility that the difference in levels of domestic savings is one of the historical reasons that countries pursued different exchange rate policies. My panel evidence is somewhat mixed. The results based on the sample of all countries are consistent with the theoretical claim that real undervaluations can mitigate more imbalances and stimulate higher growth when the level of domestic savings is high. However, for the sample of developing countries, the results indicate that initial level of domestic savings does not matter for the growth-promoting effect of real undervaluation. On the contrary, it does matter across developed countries where internal imbalances are supposed to be less common relative to developing countries. This study suggests that more theoretical and empirical investigation is necessary in the future to disclose further the mechanism through which real undervaluations boost long-run growth.

This dissertation covers both policy-oriented and theory-based topics in International Economics. The first two chapters cover financial policy related to the capital account, while the third chapter covers tariff policy related to the current account. The first chapter examines the theoretical value of capital controls in reducing the probability of bank runs. I develop a global game model with information-based bank runs and strategic complementarities within and between foreign and domestic creditors. My analysis appears to be the first to model the interconnectedness of foreign and domestic creditor behavior. The framework pins down the probability of a bank run and shows that a capital control can lower the probability of a domestic bank run and of capital flight. I also find that a control on outflows is relatively more effective than a control on inflows. Finally, I test the model's implications using the abnormal returns of Brazilian and South Korean bank stock prices as a proxy for the probability of bank runs. The second chapter analyzes the policy actions of Brazil and Chile between 2009 and the third quarter of 2011, when Brazil deployed capital account regulations and Chile intervened in its currency markets. I examine the effectiveness of each of these actions and the extent to which the actions of Brazil caused capital flow spillovers in the Chilean market. Consistent with the peer-reviewed literature on the subject, I find that capital account regulations had small but significant effects on the shifting the composition of capital inflows toward longer-term investment, on the level and volatility of the exchange rate, on asset prices, and on the ability of Brazil to have independence in monetary policy. Brazil's regulations did also temporarily cause an increase in capital flows into Chile. Chile's interventions did not have a lasting impact on the Chilean exchange rate or on asset prices beyond the initial announcements of the policies. In Brazil's case we thus conclude that Brazil's regulations helped the nation 'lean against the wind,' but were not enough to tame the 'tsunami' of post-crisis capital flows. The third chapter uses a computable general equilibrium (CGE) model calibrated to late nineteenth century parameters to show that protectionism alleviated the skilled wage gap. Had the U.S. chosen free trade instead of protective tariffs, wage inequality generally would have been higher in the post-bellum era. The imposition of high tariffs after the Civil War may have dampened what some economic historians believe to have been a long-term upward trend in inequality--the rising portion of the American-Kuznets' curve.

This dissertation examined the California Music Project Teacher Training Program, which was designed to address inequities of music education in high poverty schools, support music teachers so they remained in those schools, and encourage preservice music teachers to build personal and professional capacity for work in under-resourced school environments. I viewed CMP within a broader framework of income inequality that directly impacted children, families and neighborhoods, and through those mechanisms indirectly impacted school functions and educational attainment for children. In light of a body of research on interventions in poverty and income inequality designed to stabilize school operations and thus improve children's educational attainment, I framed CMP as a similar intervention, designed to stabilize music programs and music teaching in the San Jose area. The San Jose site of CMP thus became the case of interest and I sought a broad cross-section of mentors and fellows associated with that site to inform the research. Data analysis revealed two systemic impacts on CMP schools: 1) California had low per-pupil spending overall, and in some CMP schools, per pupil spending was lower than the state average; and 2) most CMP schools were required to provide remedial instruction for large numbers of students. Due to budgetary pressures from remedial programs, there were few funds available for music programs, and due to the many students who needed remedial instruction in CMP schools, overall music enrollment was low, yet class sizes were large. The mentors were sustained in several ways by having fellows who helped in their music classrooms; however, mentors did not attribute their longevity to CMP, and several CMP mentors left their teaching positions in under-resourced schools. Prior to 2012, most fellows initially became employed as music teachers in under-resourced schools, but only a few remained in those positions.

ABSTRACT This dissertation examines the years 1980-2000 as a sociologically transformative period in Boston's history. The guiding research question is how organized politics and the policies that emerged responded to racial conflict, inequality and economic development, and wholesale change in the city's economic base during this period. The policies of the three governing regimes--the end of Kevin H. White's sixteen-year term, Raymond L. Flynn's nine years in office, and the beginning of Thomas M. Menino's twenty-year mayoralty--are analyzed in the content of these domains to identify the outcomes of several policy agendas that have helped shape life in Boston today. This analysis is in the context of urbanization and urbanism, viewed through the lenses of urban regime, growth machine coalition, progressive city, and government communalism theories. The study utilizes retrospective autoethnography linked with interviews and archival data research. The study found that during the end of the mayoral administration of Kevin White, Boston was in turmoil politically and racially. Political contests centered on growing poverty and inequality and racial unrest in the city. The election of 1983 was a "critical election" both because an African American was in the final runoff and because the two finalists repudiated the growth machine coalition and the racial politics of the past. Flynn's election began the populist transformation of economic policies in Boston to heal racial divisions. After he resigned to become Ambassador to the Vatican, the urban regime of Thomas Menino left intact many of the redistributive policies Flynn enacted; however, it also gradually returned to the growth machine coalition model of economic development, fueling the greatest class and income inequality in Boston's history. In the final analysis, both the policies of each urban regime and the activities of the religious, cultural, business, and neighborhood organizations that comprise city life changed the city in sociologically significant ways. This is the story of Boston 1980-2000, the role of its three mayors during that period, and how the city entered the twenty-first century with its physical decline in part reversed but with issues of race and class remaining significant touchstones.

This thesis studies Ricci solitons of cohomogeneity one and uniform Poincaré inequalities for differentials on Riemann surfaces. In the two summands case, which assumes that the isotropy representation of the principal orbit consists of two inequivalent Ad-invariant irreducible summands, complete steady and expanding Ricci solitons have been detected numerically by Buzano-Dancer-Gallaugher-Wang. This work provides a rigorous construction thereof. A Lyapunov function is introduced to prove that the Ricci soliton metrics lie in a bounded region of an associated phase space. This also gives an alternative construction of non-compact Einstein metrics of non-positive scalar curvature due to Böhm. It is explained how the asymptotics of the Ricci flat trajectories induce Böhm's Einstein metrics on spheres and other low dimensional spaces. A numerical study suggests that all other Einstein metrics of positive scalar curvature which are induced by the generalised Hopf fibrations occur in an entirely non-linear regime of the Einstein equations. Extending the theory of cohomogeneity one steady and expanding Ricci solitons, an estimate which allows to prescribe the growth rate of the soliton potential at any given time is shown. As an application, continuous families of Ricci solitons on complex line bundles over products of Fano Kähler Einstein manifolds are constructed. This generalises work of Appleton and Stolarski. The method also applies to the Lü-Page-Pope set-up and allows to cover an optimal parameter range in the two summands case. The Ricci soliton equation on manifolds foliated by torus bundles over products of Fano Kähler Einstein manifolds is discussed. A rigidity theorem is obtained and a preserved curvature condition is discovered. The cohomogeneity one initial value problem is solved for m-quasi-Einstein metrics and complete metrics are described. L^p-Poincaré inequalities for k-differentials on closed Riemann surfaces are shown. The estimates are uniform in the sense that the Poincaré constant only depends on p ≥1, k ≥ 2 and the genus γ ≥ 2 of the surface but not on its complex structure. Examples show that the analogous estimate for 1-differentials cannot be uniform. This part is based on joint work with Melanie Rupflin.

Let X be a smooth complex projective variety. In 2002, [Bri07] defined a notion of stability for the objects in Db(X), the bounded derived category of coherent sheaves on X, which generalized the notion of slope stability for vector bundles on curves. There are many nice connections between stability conditions on X and the geometry of the variety. In 2012, [BMT14] gave a conjectural stability condition for threefolds. In the case that X is a complete intersection threefold, the existence of this stability condition would imply a Castelnuovo-type inequality for curves on X. I give a new Castelnuovo-type inequality for curves on complete intersection surfaces of high degree. I then show how this bound would imply the bound conjectured in [BMT14] if a weaker bound could be shown for curves of lower degree. I also construct new stability conditions for surfaces containing a curve C whose self-intersection is negative. I show that these stability conditions lie on a wall of the geometric chamber of Stab(X), the stability manifold of X. I then construct the moduli space Mσ (OX) of σ-semistable objects of class [OX] in K0(X) after wall-crossing.

Aim Despite the country's explicit political goal to establish equivalent living conditions across Germany, significant inequality continues to exist. We argue that premature mortality is an excellent proxy variable for testing the claim of equivalent living conditions since the root causes of premature death are socioeconomic. Subject and methods We analyse variation in premature mortality across Germany's 402 districts and cities in 2014. Results Premature mortality spatially clusters among geographically contiguous and proximate districts/cities and is higher in more urban places as well as in districts/cities located further north and in former East Germany. We demonstrate that, first, socioeconomic factors account for 62% of the cross-sectional variation in years of potential life lost and 70% of the variation in the premature mortality rate. Second, we show that these socioeconomic factors either entirely or almost fully eliminate the systematic spatial patterns that exist in premature mortality. Conclusion On its own, fiscal redistribution, the centrepiece of how Germany aspires to establish its political goal, cannot generate equivalent living conditions in the absence of a comprehensive set of economic and social policies at all levels of political administration, tackling the disparities in socioeconomic factors that collectively result in highly unequal living conditions.