Graded algebra automorphisms

We consider the Clifford algebra C(q) of a regular quadratic space (V, q) over a field K with its structure of Z/2Z-graded K-algebra. We give a characterization of the group of graded automorphisms of C(q). In the last section we introduce the Z/nZ-graded algebras and we study as well as the group of graded automorphisms for some of them.

L'esquema universal de clústers de 2-seccions d'una família de superfícies

Generalitzem el concepte de clúster de punts d'una superfície a clúster de seccions d'una família de superfícies per passar al cas relatiu, és a dir, a clústers de B-punts d'una B-superfície. Llavors definim, amb una propietat universal, la família universal de clusters de 2-seccions d'una família de superfícies, que, en cas que existir, és un esquema que parametritza tots els clústers de 2-seccions d'una famíla de superfícies. Demostrem la seva existencia sota certes hipotesis i trobem que es pot construir en termes de blowups a partir del producte de la família universal de seccions de la fmília de superficies per si mateixa. Al final del treball hi ha tres exemples que mostren part de la teoria estudiada.

In search of mathematical primitives for deriving universal projective hash families

We provide some guidelines for deriving new projective hash families of cryptographic interest. Our main building blocks are so called group action systems; we explore what properties of this mathematical primitives may lead to the construction of cryptographically useful projective hash families. We point out different directions towards new constructions, deviating from known proposals arising from Cramer and Shoup's seminal work.

When does universal peace prevail? Secession and group formation in rent seeking contests and policy conflicts

This paper analyzes secession and group formation in a general model of contest inspired by Esteban and Ray (1999). This model encompasses as special cases rent seeking contests and policy conflicts, where agents lobby over the choice of a policy in a one-dimensional policy space. We show that in both models the grand coalition is the efficient coalition structure and agents are always better off in the grand coalition than in a symmetric coalition structure. Individual agents (in the rent seeking contest) and extremists (in the policy conflict) only have an incentive to secede when they anticipate that their secession will not be followed by additional secessions. Incentives to secede are lower when agents cooperate inside groups. The grand coalition emerges as the unique subgame perfect equilibrium outcome of a sequential game of coalition formation in rent seeking contests.

How universal is behavior? A four country comparison of spite, cooperation and errors in voluntary contribution mechanisms

This paper studies behavior in experiments with a linear voluntary contributions mechanism for public goods conducted in Japan, the Netherlands, Spain and the USA. The same experimental design was used in the four countries. Our 'contribution function' design allows us to obtain a view of subjects' behavior from two complementary points of view. If yields information about situations where, in purely pecuniary terms, it is a dominant strategy to contribute all the endowment and about situations where it is a dominant strategy to contribute nothing. Our results show, first, that differences in behavior across countries are minor. We find that when people play "the same game" they behave similarly. Second, for all four countries our data are inconsistent with the explanation that subjects contribute only out of confusion. A common cooperative motivation is needed to explain the date.

La Accesibilidad universal y el diseño para todos: los ejes determinantes de las políticas de igualdad de oportunidades III

Capítol del llibre "Tratado sobre la discapacidad", R. De Lorenzo, L. Cayo Pérez Bueno. Navarra: Thomson Aranzadi,2007. Planteja el significat dels conceptes "Accessibilitat Universal", que és fonamentalment la condició que han de complir els entorns, processos, bens, productes i serveis, així com els objectes o instruments, eines i dispositius, per a ser comprensibles, utilitzables i practicables per a totes les persones en condicions de seguretat i comoditat i de la manera més autònoma possible.. Això pressuposa el "Disseny per a tothom" i s'entén que sense perjudici dels ajustos raonables que s'hagin d'adoptar.

Projective modules over the Gerasimov-Sakhaev counterexample

We investigate the structure of the so-called Gerasimov- Sakhaev counterexample, which is a particular example of a universal localization, and classify (both finitely and infinitely generated) projective modules over it.

La Accesibilidad universal en los municipios: guía para una política integral de promoción y gestión

Conscientes de las complejidades que presenta la organización administrativa local y la diversidad que caracteriza a los Ayuntamientos de España, y lejos de querer establecer fórmulas mágicas o generalizar soluciones, con esta Guía se pretende aportar ideas útiles mediante propuestas y algunos ejemplos; con ella se quiere ayudar a promover distintas intervenciones a favor de la accesibilidad en los municipios. En este sentido, esta Guía pretende ser soporte para desarrollar una nueva etapa de intervención municipal en accesibilidad, que vaya más allá de la mera supresión de barreras y se prevenga su creación. Las medidas que se desarrollan son posibles vías para que los gobiernos locales puedan gestionar y promocionar de forma eficaz la accesibilidad en el municipio y así establecer una base sobre la cual todos los ciudadanos puedan desarrollar sus libertades individuales plenamente.

Guía para el diseño e implementación de un master en accesibilidad universal. La aplicación del diseño para todos en entornos, productos y servicios

Esta Guía nace con la intención de impulsar en esta situación poco favorable el desarrollo del mencionado curso de postgrado en la universidad española. En ese sentido, pretende ser un recurso a utilizar por el profesorado universitario y el grupo de expertos en accesibilidad que constituya el futuro equipo docente de esta iniciativa formativa, como punto de partida para el necesario proceso de concreción curricular que tendrán que realizar. Queremos destacar aquí que esta guía no se concibe, por tanto, como el programa de un Master en accesibilidad Universal, aunque incluye a modo de ejemplo una propuesta concreta, sino como un conjunto de recursos a utilizar para elaborarlo, respetando así el principio de autonomía universitaria y docente en el que creemos firmemente.

On the trace of an endofunctor of a small category

The trace of a square matrix can be defined by a universal property which, appropriately generalized yields the concept of "trace of an endofunctor of a small category". We review the basic definitions of this general concept and give a new construction, the "pretrace category", which allows us to obtain the trace of an endofunctor of a small category as the set of connected components of its pretrace. We show that this pretrace construction determines a finite-product preserving endofunctor of the category of small categories, and we deduce from this that the trace inherits any finite-product algebraic structure that the original category may have. We apply our results to several examples from Representation Theory obtaining a new (indirect) proof of the fact that two finite dimensional linear representations of a finite group are isomorphic if and only if they have the same character.

An irreducibility criterion for group representations, with arithmetic applications

We prove a criterion for the irreducibility of an integral group representation p over the fraction field of a noetherian domain R in terms of suitably defined reductions of p at prime ideals of R. As applications, we give irreducibility results for universal deformations of residual representations, with a special attention to universal deformations of residual Galois representations associated with modular forms of weight at least 2.

Double adjunctions

We characterize double adjunctions in terms of presheaves and universal squares, and then apply these characterizations to free monads and Eilenberg-Moore objects in double categories. We improve upon an earlier result of Fiore-Gambino-Kock in [7] to conclude: if a double category with cofolding admits the construction of free monads in its horizontal 2-category, then it also admits the construction of free monads as a double category horizontally and vertically, and also in its vertical 2-category. We also prove that a double category admits Eilenberg-Moore objects if and only if a certain parameterized presheaf is representable. Along the way, we develop parameterized presheaves on double categories and prove a double Yoneda Lemma.

Cultural relativism in the Universal Periodic Review of the Human Rights Council

This Working Paper aims to offer an up-to-date list of cultural relativist players and arguments with respect to human rights, constituted by China, Viet Nam, Myanmar, Iran, Pakistan, Yemen, Syria, Malaysia and Cuba. This working paper argues that Indonesia, Iraq, Colombia and Mexico are not in the same cultural relativist group of states maintained by renowned scholars, notably Cristina Cerna and Dianne Otto. As such, apart from this form of cultural relativism based on the respect for the self-determination of indigenous peoples and communities, this working paper exposes two different categories of radical cultural relativism based on revolutionary discourse and/or radical Islamism, as well as targets the credibility on the latter two based on the information facilitated by the United Nations (UN) Human Rights Council (HRC) Universal Periodic Review (UPR).

Creació d'una ontologia universal

L'objectiu d'aquest treball és introduir al lector en les tecnologies que condueixen al desenvolupament de la web semàntica, destacant-ne les parts més importants d'aquestes i veient com cadascuna amplia la funcionalitat de la seva predecessora a l'hora d'aportar un sentit semàntic als documents.

Creació d'una ontologia universal

Aquest treball consisteix en el disseny d'una ontologia universal sobre el domini de l'alimentació. L'ontologia es definirà utilitzant les eines necessàries proposades pel W3C per a la construcció de la web semàntica.