On the value of optimal stopping games

We show, under weaker assumptions than in the previous literature, that a perpetual optimal stopping game always has a value. We also show that there exists an optimal stopping time for the seller, but not necessarily for the buyer. Moreover, conditions are provided under which the existence of an optimal stopping time for the buyer is guaranteed. The results are illustrated explicitly in two examples.Comment: Published at http://dx.doi.org/10.1214/105051606000000204 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Representation through deliberation-The European case

This article shows that the main pattern of European democratization has unfolded along the lines of an EU organized as a multilevel system of representative parliamentary government and not as a system of deliberative governance as the transnationalists propound. But the multilevel EU has developed a structure of representation that is theoretically challenging. In order to come to grips with this we present an institutional variant of deliberative theory, which understands democracy as the combination of a principle of justification and an organizational form. It comes with the following explanatory mechanisms: claimsmaking, justification and learning which in the EU also program institutional copying and emulation mechanisms. We show that the EU has established an incomplete system of representative democracy steeped in a distinct representation-deliberation interface, which has emerged through a particular and distinct configuration of democratization mechanisms

"Europe in Transformation: How to Reconstitute Democracy?"

Europeanization and globalization are frequently held to undermine national democracy; hence raising the democracy in the multi-level constellation that makes up the European Union? We present three models for how democracy can be reconstituted: (a) it can be reconstituted at the national level, as delegated democracy with a concomitant reframing of the EU as a functional regulatory regime; (b) through establishing the EU as a multi-national state based on a common identity(ies) and solidaristic allegiance strong enough to undertake collective action; or (c) through the development of a post-national Union with an explicit cosmopolitan imprint. These are the only viable models of European democracy, as they are the only ones that can ensure equal membership in a self-governing polity. They differ however with regard to both applicability and robustness

Performance and Optimization Abstractions for Large Scale Heterogeneous Systems in the Cactus/Chemora Framework

We describe a set of lower-level abstractions to improve performance on modern large scale heterogeneous systems. These provide portable access to system- and hardware-dependent features, automatically apply dynamic optimizations at run time, and target stencil-based codes used in finite differencing, finite volume, or block-structured adaptive mesh refinement codes. These abstractions include a novel data structure to manage refinement information for block-structured adaptive mesh refinement, an iterator mechanism to efficiently traverse multi-dimensional arrays in stencil-based codes, and a portable API and implementation for explicit SIMD vectorization. These abstractions can either be employed manually, or be targeted by automated code generation, or be used via support libraries by compilers during code generation. The implementations described below are available in the Cactus framework, and are used e.g. in the Einstein Toolkit for relativistic astrophysics simulations

Know all men by these presents: bonds, localism and politics in early Republican Mississippi

This article examines local politics in Mississippi during the early to mid-nineteenth century, by examining the bonds that officeholders were required to post to hold their positions in county government. The article argues that while states like Mississippi remain at the forefront of the history of American mass democracy, the existence of this election ritual paints a complicated picture of political practice. By requiring officeholders to post hundreds and even thousands of dollars to hold office, and by requiring that political friends vouch for them with their money and their reputations, bonds dampened democratic elections at every turn. In so doing, bonds suggest just some of the ways in which Americans practiced a much more complex politics than current paradigms allow

8 Lectures on quantum groups and q-special functions

Lecture notes for an eight hour course on quantum groups and $q$-special functions at the fourth Summer School in Differential Equations and Related Areas, Universidad Nacional de Colombia and Universidad de los Andes, Bogot\'a, Colombia, July 22 -- August 2, 1996. The lecture notes contain an introduction to quantum groups, $q$-special functions and their interplay. After generalities on Hopf algebras, orthogonal polynomials and basic hypergeometric series we work out the relation between the quantum SU(2) group and the Askey-Wilson polynomials out in detail as the main example. As an application we derive an addition formula for a two-parameter subfamily of Askey-Wilson polynomials. A relation between the Al-Salam and Chihara polynomials and the quantised universal enveloping algebra for $su(1,1)$ is given. Finally, more examples and other approaches as well as some open problems are given.Comment: AMS-TeX, 82 page