Two applications of difference methods to chains of linear oscillators

M.S.M. B. Sled

Stimulating innovation in Russia: the role of institutions and policies

This paper examines the potential role of innovation policy in enhancing long-term productivity growth in Russia. It begins by exploring the role of framework conditions for business in encouraging innovative activities, particularly with respect to intellectual property rights and competition. Realising Russia’s innovation potential will also require reform of the large public science sector. This raises issues pertaining to the organisation and financing of public research bodies and, in particular, to the incentives and opportunities they face in commercialising the results of their research. Finally, the paper looks at the potential role of direct interventions, such as special economic zones and technoparks, as well as the scope for improving the tax regime for private-sector R&D

Too little destruction, too little creation: a Schumpeterian diagnosis of the barriers to sustained growth in Ukraine

This paper examines problems of entry, exit and competition in Ukrainian product markets. It finds that Ukraine still has too little of all three, and that exit mechanisms, in particular, function poorly. Since impediments to entry and exit are largely the product of excessive and ill administered regulation, the paper also provides a systematic assessment of product-market regulation in Ukraine, using indicators developed by the OECD Economics Department. Finally, the paper presents the main findings of two empirical studies concerned with the potentially large benefits of opening up markets, via both increased competition and further privatisation, for productivity growth in Ukraine. * * * * * Cet article examine les questions de concurrence, d’entrée et de sortie des entreprises sur le marché des biens. Il montre que toutes trois demeurent insuffisantes en Ukraine, et que les mécanismes de sortie du marché, en particulier, fonctionnent de manière très imparfaite. Compte tenu du fait que les barrières à l’entrée et à la sortie sont largement le produit d’une réglementation excessive et mal appliquée, l’article donne une évaluation systématique du niveau de réglementation du marché des biens en Ukraine, en utilisant les indicateurs développés par le Département des affaires économiques. Enfin, l’article expose les principaux résultats de deux études empiriques évaluant les effets bénéfiques sur la croissance de la productivité de l’ouverture des marchés, d’une part par un accroissement de la concurrence et d’autre part par la poursuite des privatisations

Hidden Symmetries and Commensurability of 2-Bridge Link Complements

In this paper, we show that any non-arithmetic hyperbolic $2$-bridge link complement admits no hidden symmetries. As a corollary, we conclude that a hyperbolic $2$-bridge link complement cannot irregularly cover a hyperbolic $3$-manifold. By combining this corollary with the work of Boileau and Weidmann, we obtain a characterization of $3$-manifolds with non-trivial JSJ-decomposition and rank two fundamental groups. We also show that the only commensurable hyperbolic $2$-bridge link complements are the figure-eight knot complement and the $6_{2}^{2}$ link complement. Our work requires a careful analysis of the tilings of $\mathbb{R}^{2}$ that come from lifting the canonical triangulations of the cusps of hyperbolic $2$-bridge link complements.Comment: This is the final (accepted) version of this pape

Prolific Inventor Productivity and Mobility: A Western/Asian com-parison. Evidence from US Patent Data for 12 Countries

This paper provides new insights into the role of individual inventors inthe innovation process. Individuals are central in this creative process becauseinnovation is not simply a product of firms and organizations; it requiresindividual creativity (Rothaermel and Hess, 2007). We focus our analysis on prolific inventors (a rich sub category of inventors) because they contribute sohugely to national invention totals (Le Bas et al., 2010) and tend to produceinventions that have more economic value (Gambardella et al., 2005; Gay et al.,2008). Converging empirical evidence has established the significance ofprolific inventors (Ernst et al., 2000). Previous studies of prolific (or “key”)inventors have focused more on the firms in which they work or on the industriesin which the firms operate. Narin and Breitzman’s (1995) seminal work on thetopic is based on an analysis of only four firms in a single sector and a recentpaper by Pilkington et al. (2009) uses only two firms. In contrast to these studieson small samples, we use a very large data set which includes thousands ofinventors in thousands of firms from several countries.Artykuł przedstawia nowe spojrzenie na rolę indywidualnych wynalazców w procesie tworzenia innowacji. Wynalazcy indywidualni stanowią element centralny procesu twórczego. Innowacja nie jest produktem firm i organizacji, wymaga indywidualnej kreatywności (Rothaermel i Hess 2007). Badanie koncentruje się na analizie płodnych wynalazców. Wynalazcy tej kategorii mają najwyższy udział w generowaniu ogółu wynalazków (Le Bas et al. 2010) o wysokiej wartości ekonkomicznej (Gambardella et al. 2005). Poprzednie badania kluczowych wynalazców skupiały się analizie firm, w których pracują lub w branżach, w których te firmy działają

"Causes, Consequences and Dynamics of 'Complex' Distributions of Technological Activities: The Case of Prolific Inventors"

We provide a framework for understanding the causes and consequences of the observed shapes of the distributions of individual inventors' productivities. We review a literature that begins with Lotka's (1926) "law" regarding the persistence of variability in scientific productivity at any point in time and also over time. We discuss use of the "power law" and the Pareto distribution to describe and explain the empirical distributions. We focus on the upper parts of the frequency distributions for inventors exploring the processes underlying knowledge accumulation at the individual level, including its features, characteristics, and structural trends. Finally we explore the specific processes by which these individuals create, maintain, and increase knowledge accumulation as their careers evolve.patents, inventors, prolific, lotka

Two-Loop Virtual Corrections to Drell-Yan Production at order alpha_s alpha^3

The Drell-Yan mechanism for the production of lepton pairs is one of the most basic processes for physics studies at hadron colliders. It is therefore important to have accurate theoretical predictions. In this work we compute the two-loop virtual mixed QCD x QED corrections to Drell-Yan production. We evaluate the Feynman diagrams by decomposing the amplitudes into a set of known master integrals and their coefficients, which allows us to derive an analytical result. We also perform a detailed study of the ultraviolet and infrared structure of the two-loop amplitude and the corresponding poles in epsilon.Comment: 20 pages, 3 figure