The {\L}ojasiewicz exponent of a set of weighted homogeneous ideals

We give an expression for the {\L}ojasiewicz exponent of a set of ideals which are pieces of a weighted homogeneous filtration. We also study the application of this formula to the computation of the {\L}ojasiewicz exponent of the gradient of a semi-weighted homogeneous function (\C^n,0)\to (\C,0) with an isolated singularity at the origin.Comment: 15 page

Log canonical threshold and diagonal ideals

We characterize the ideals $I$ of $\mathcal O_n$ of finite colength whose integral closure is equal to the integral closure of an ideal generated by pure monomials. This characterization, which is motivated by an inequality proven by Demailly and Pham, is given in terms of the log canonical threshold of $I$ and the sequence of mixed multiplicities of $I$.Comment: Updated versio

SENSITIVITY ANALYSIS OF EFFICIENCY AND MALMQUIST PRODUCTIVITY INDICES: AN APPLICATION TO SPANISH SAVINGS BANKS

Hypothesis testing and statistical precision in the context of nonparametric efficiency and productivity measurement have been investigated since the early 1990s. Recent contributions focus on this matter through the use of resampling methods?i.e., bootstrapping techniques. However, empirical evidence is still practically non-existent. This gap is more noticeable in the case of banking efficiency studies, where the literature is immense. In this paper, we explore productivity growth and productive efficiency for Spanish savings banks over the (initial) post-deregulation period 1992?1998 using Data Envelopment Analysis (DEA) and bootstrapping techniques. Results show that productivity growth has occurred, mainly due to improvement in production possibilities, and that mean efficiency has remained fairly constant over time. The bootstrap analysis yields further evidence, as for many firms productivity growth, or decline, is not statistically significant. With regard to efficiency measurement, the bootstrap reveals that the disparities in the original efficiency scores of some firms are lessened to a great extent. Desde principios de los años noventa ha habido avances notables en el contraste de hipótesis dentro del contexto de la medición de la eficiencia y la productividad mediante técnicas paramétricas. Las contribuciones más recientes han enfocado el tema a través de métodos de remuestreo -conocidos en la literatura como técnicas bootstrap-. Sin embargo, prácticamente no ha habido aplicaciones, algo también patente en el estudio de la eficiencia de la empresa bancaria. En este artículo, analizamos la eficiencia productiva y el crecimiento de la productividad de las cajas de ahorro españolas durante el periodo 1992-1998 a través de técnicas no paramétricas (DEA) y de técnicas bootstrap, con el fin de poder realizar inferencia estadística. Los resultados indican que la productividad ha aumentado, principalmente debido a una mejora en las posibilidades de producción, mientras que la eficiencia promedio no ha variado sustancialmente. El análisis bootstrap revela que, en el caso de la productividad, para muchas empresas su aumento o disminución no es estadísticamente significativo. En cuanto a la eficiencia, muestra que las diferencias entre empresas individuales se reducen de manera notable cuando consideramos intervalos de confianza.bootstrap, data envelopment analysis, efficiency, productivity, savings bank bootstrap, técnicas no paramétricas, eficiencia, productividad, cajas de ahorro.

Lojasiewicz exponent of families of ideals, Rees mixed multiplicities and Newton filtrations

We give an expression for the {\L}ojasiewicz exponent of a wide class of n-tuples of ideals $(I_1,..., I_n)$ in \O_n using the information given by a fixed Newton filtration. In order to obtain this expression we consider a reformulation of {\L}ojasiewicz exponents in terms of Rees mixed multiplicities. As a consequence, we obtain a wide class of semi-weighted homogeneous functions $(\mathbb{C}^n,0)\to (\mathbb{C},0)$ for which the {\L}ojasiewicz of its gradient map $\nabla f$ attains the maximum possible value.Comment: 25 pages. Updated with minor change

PRODUCT MIX OF THE SPANISH BANKING FIRMS: DO COMPETITION CLUBS EXIST?

The expansion and intensification of banking competition, which has occurred inSpain during the last ten years, has allowed banks and savings banks to define theircompetitive strategies with more freedom. This paper analyzes the similarities andthe differences in their product mix along with its time evolution. In particular, itattempts to identify the different kinds of firms and, on this ground, to analyze whethercompetition leads to the homogeneization (convergence) of product mixes betweenfirms or groups of firms (clubs). The empirical success is higher when specializationclubs are considered, finding increased heterogeneity within the banking system as awhole but increased homogeneity within certain clusters of banks and savings banks La expansión e intensificación de la competencia en el sector bancario ocurrida en España durante la última década ha permitido a bancos y cajas de ahorro definir sus estrategias competitivas con mayor libertad. Este artículo analiza las similitudes y diferencias en la especialización de las empresas bancarias y su evolución temporal. En particular, trata de identificar los distintos tipos de empresas y, a partir de ello, analizar si la competencia está condicionada o no por grupos (clubes) de competidores con especializaciones similares. Los resultados son superiores cuando se consideran clubes de especialización, obteniéndose heterogeneidad creciente para el conjunto del sistema bancario pero homogeneidad creciente dentro de ciertos grupos de bancos y cajas de ahorro.sector bancario, convergencia, especialización productiva banking, convergence, product mix

The determinants of international financial integration revisited: the role of networks and geographic neutrality

Over the last two decades, the degree of international financial integration has increased substantially, becoming an important area of research for many financial economists. This paper explores the determinants of the asymmetries in the international integration of banking systems. We consider an approach based on both network analysis and the concept of geographic neutrality. Our analysis focuses on the banking systems of 18 advanced economies from 1999 to 2005. Results indicate that banking integration should be assessed from the perspective of both inflows and outflows, given that they show different patterns for different countries. Using standard techniques, our results reinforce previous findings by the literature—especially the remarkable role of both geographic distance and trade integration. Nonparametric techniques reveal that the effect of the covariates on banking integration is not constant over the conditional distribution which (in practical terms) implies that the sign of the relationship varies across countries.banking integration, geographic neutrality, network analysis, nonparametric regression

On the Dynamics of Globalization

How has the process of international economic integration advanced over the last four decades? How will the foreseeable future look like? We attempt to answer this sort of questions by considering some methods which have scarcely been used in the literature on globalization. First, we consider a set of indicators which measure not only the degree of openness of economies, but also how connected they are to each other, following Arribas et al. (2007). Second, we assess how these indicators have evolved over time, what the likely steady state distribution might be, and whether results differ depending on a variety of weighting schemes (GDP, population). Results show that, under current trends, the future world will be much more integrated, especially for the most heavily populated countries. However, there is still a long way to go before the Standard of Perfect International Integration can be achieved.International Economic Integration, Globalization, International Trade, Network Analysis, Distribution Dynamics

Measuring International Economic Integration: Theory and Evidence of Globalization

This article features a set of indicators designed to measure international economic integration and globalization. We analyze the degree of openness and the respective networks of connections---both direct and indirect---for each economy in our sample. Our indicators are based on network analysis techniques and the exchange of flows among world economies. Starting from four basic axioms of international economic integration, we define the Standard of Perfect International Integration, along with the set of indicators for degree of openness and connectedness, both for each specific economy and for the world economy as a whole. We apply our indicators to data on trade flows for 59 countries---accounting for 96.7% of world output---for the 1967--2004 period. According to our results, international economic integration is higher than what traditional degree of openness indicators suggest. The advance of globalization is unequal among countries because of the differing trends in their degree of openness and the differences in the intensity with which economies are connected to each other. Several economies now appear to be internationally integrated; however, the relatively low degree of openness in some of the largest economies jeopardizes the progress of globalization. We also perform some simulations which suggest that, should technological progress lead to an increase in indirect connections, the move towards greater international economic integration would accelerate.International Economic Integration, Globalization, International Trade, Network Analysis