Reflexivity of the isometry group of some classical spaces

We investigate the reflexivity of the isometry group and the automorphism group of some important metric linear spaces and algebras. The paper consists of the following sections: 1. Preliminaries. 2. Sequence spaces. 3. Spaces of measurable functions. 4. Hardy spaces. 5. Banach algebras of holomorphic functions. 6. Frechet algebras of holomorphic functions. 7. Spaces of continuous functions.Comment: 18 pages. To appear in Rev. Mat. Iberoa

A Faster Parameterized Algorithm for Treedepth

The width measure \emph{treedepth}, also known as vertex ranking, centered coloring and elimination tree height, is a well-established notion which has recently seen a resurgence of interest. We present an algorithm which---given as input an $n$-vertex graph, a tree decomposition of the graph of width $w$, and an integer $t$---decides Treedepth, i.e. whether the treedepth of the graph is at most $t$, in time $2^{O(wt)} \cdot n$. If necessary, a witness structure for the treedepth can be constructed in the same running time. In conjunction with previous results we provide a simple algorithm and a fast algorithm which decide treedepth in time $2^{2^{O(t)}} \cdot n$ and $2^{O(t^2)} \cdot n$, respectively, which do not require a tree decomposition as part of their input. The former answers an open question posed by Ossona de Mendez and Nesetril as to whether deciding Treedepth admits an algorithm with a linear running time (for every fixed $t$) that does not rely on Courcelle's Theorem or other heavy machinery. For chordal graphs we can prove a running time of $2^{O(t \log t)}\cdot n$ for the same algorithm.Comment: An extended abstract was published in ICALP 2014, Track

Enterprise reference architectures for higher education institutions: Analysis, comparison and practical uses

Enterprise Architecture (EA) is currently accepted as one on the major instruments for enabling organisations in their transformation processes to achieve business-technology alignment. Despite that over the last years EA has been successfully adopted in many industries, Higher Education still represents one of the sectors with lower levels of adoption and maturity of EA practices. The present thesis puts the emphasis particularly on the study Enterprise Reference Architectures (ERAs), as a particular type of EA artefact, in Higher Education Institutions (HEIs). After formally clarifying the concept of ERAs and giving a panoramic view of the current state-of-the-art of existing HEI-oriented ERAs, the thesis proposes an artefact framework build through a Design Science Research (DSR) approach aimed to facilitate practitioners their (re-)use or application in their own real practical settings. The purpose of the constructed artefact is to support practitioners when conducting the necessary adjustments to exiting HEI-oriented ERAs in order to be successfully applied for their specific needs.La Arquitectura Empresarial (AE) es actualmente reconocida como una disciplina que permite configurar procesos de trasformación organizativa a objeto de alinear el negocio con la tecnología. A pesar de que en los últimos años la AE se ha ido adoptando progresivamente de forma exitosa en diversas industrias, la educación superior representa todavía hoy en día uno de los sectores con menores niveles de adopción y de madurez en lo que se refiere a las prácticas de AE. La presente tesis hace especial hincapié en el estudio de las Arquitecturas de Referencia Empresariales (AREs), entendidas como un artefacto específico de AE, en Instituciones de Educación Superior (IES). Así, después de clarificar formalmente el concepto de ARE y de ofrecer una visión panorámica del estado del arte relativo a las AREs para IES existentes, la tesis propone un framework de trabajo construido a través de un enfoque de investigación basado en la Ciencia del diseño destinado a facilitar su (re-)utilización o aplicación práctica en dominios de trabajo reales. El objetivo del artefacto es proporcionar soporte práctico a los profesionales para realizar los ajustes necesarios a las AREs para IES existentes para que puedan aplicarlas con éxito a sus necesidades específicas.L'Arquitectura Empresarial (AE) és actualment reconeguda com una disciplina que permet configurar processos de transformació organitzatius a fi d'alinear el negoci amb la tecnologia. Tot i que en els darrers anys l'AE s'ha anat adoptant progressivament amb èxit en diverses indústries, l'educació superior representa encara avui dia un dels sectors amb menors nivells d'adopció i de maduresa pel que fa a pràctiques d'AE. Aquesta tesi posa especial èmfasi en l'estudi de les Arquitectures de Referència Empresarials (AREs), enteses com un artefacte concret d'AE, a Institucions d'Educació Superior (IES). Així, després d'aclarir formalment el concepte d'ARE i oferir una visió panoràmica de l'estat de l'art relatiu a les ARE per a IES existents, la tesi proposa un framework de treball construït a través d'un enfocament de recerca basat en la ciència del disseny destinat a facilitar-ne la seva (re-)utilització o aplicació pràctica en dominis de treball reals. L'objectiu de l'artefacte és proporcionar suport pràctic als professionals per realitzar els ajustaments necessaris a les AREs per a IES existents de forma que les puguin aplicar amb èxit a les seves necessitats específiques.Tecnologies de la informació i de xarxe

Seven views on approximate convexity and the geometry of K-spaces

As in Hokusai's series of paintings "Thirty six views of mount Fuji" in which mount Fuji's is sometimes scarcely visible, the central topic of this paper is the geometry of $K$-spaces although in some of the seven views presented $K$-spaces are not easily visible. We study the interplay between the behaviour of approximately convex (and approximately affine) functions on the unit ball of a Banach space and the geometry of Banach K-spaces.Comment: 2 figure

Mirage Torsion

Z_NxZ_M orbifold models admit the introduction of a discrete torsion phase. We find that models with discrete torsion have an alternative description in terms of torsionless models. More specifically, discrete torsion can be 'gauged away' by changing the shifts by lattice vectors. Similarly, a large class of the so-called generalized discrete torsion phases can be traded for changing the background fields (Wilson lines) by lattice vectors. We further observe that certain models with generalized discrete torsion are equivalent to torsionless models with the same gauge embedding but based on different compactification lattices. We also present a method of classifying heterotic Z_NxZ_M orbifolds.Comment: 26 pages, 3 figures, v2: matches version published in JHE

The decays h+- -> W-+ h0(a0) within an extension of the MSSM with one complex Higgs triplet

The vertex H+-W-+h0, involving the gauge bosons W-+, the charged (H+-) and the lightest neutral (h0) Higgs bosons, arises within the context of many extensions of the SM, and it can be used to probe the Higgs sector of such extensions via the decay H+- -> W+- h0. We discuss the strength of this vertex for an extension of the MSSM with an additional complex Higgs triplet. By using this model, we find regions of the parameter space where the decay H+- -> W+- h0 is not only kinematically allowed, but it also becomes an important decay mode and in some cases the dominant one.Comment: 10 figure

More on Virendeel trusses to build great roofs

p. 1318-1327Years ago we built a large cover to demonstrate the great possibilities that the Vierendeel solution has to solve double curved roof surfaces. It was the Dos Hermanas Velodrome, a good example of this solution. Now we have planned to solve a large cantilever roof spanning 140 m. with a similar solution. For the velodrome we proposed a double curvature shell form in positive Gauss curvature. At present we propose a negative one. In this paper we will consider the design, analysis and construction of such an idea from the first sketches to the final results. The advantages of the proposal are important: Lightness, clarity, economy and good appearance.Escrig, F.; Sanchez, J. (2010). More on Virendeel trusses to build great roofs. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/707

Stress-strain behaviour of the sediments in the tertiary basins associated with the Alentejo? Plasencia fault in the province of Caceres (Spain)

An analysis of the geotechnical information obtained from a large number of field tests (pressuremeter) and laboratory tests (identification, state, and mechanics) on the clay deposits in the small tertiary basins associated with the Alentejo?Plasencia fault in the province of Caceres (Spain) has made it possible to classify them and predict their response to different levels of stress and strain. This geotechnical classification process must consider an appropriate model of constitution. The present article is based on the use of the Hardening Soil Model to facilitate predictions of the stress?strain behaviour of these tertiary clay deposits

Mechanistic differences between methanol and dimethyl ether in zeolite-catalyzed hydrocarbon synthesis

Water influences critically the kinetics of the autocatalytic conversion of methanol to hydrocarbons in acid zeolites. At very low conversions but otherwise typical reaction conditions, the initiation of the reaction is delayed in presence of H$_{2}$O. In absence of hydrocarbons, the main reactions are the methanol and dimethyl ether (DME) interconversion and the formation of a C$_{1}$ reactive mixture—which in turn initiates the formation of first hydrocarbons in the zeolite pores. We conclude that the dominant reactions for the formation of a reactive C$_{1}$ pool at this stage involve hydrogen transfer from both MeOH and DME to surface methoxy groups, leading to methane and formaldehyde in a 1:1 stoichiometry. While formaldehyde reacts further to other C$_{1}$ intermediates and initiates the formation of first C–C bonds, CH$_{4}$ is not reacting. The hydride transfer to methoxy groups is the rate-determining step in the initiation of the conversion of methanol and DME to hydrocarbons. Thus, CH$_{4}$ formation rates at very low conversions, i.e., in the initiation stage before autocatalysis starts, are used to gauge the formation rates of first hydrocarbons. Kinetics, in good agreement with theoretical calculations, show surprisingly that hydrogen transfer from DME to methoxy species is 10 times faster than hydrogen transfer from methanol. This difference in reactivity causes the observed faster formation of hydrocarbons in dry feeds, when the concentration of methanol is lower than in presence of water. Importantly, the kinetic analysis of CH$_{4}$ formation rates provides a unique quantitative parameter to characterize the activity of catalysts in the methanol-to-hydrocarbon process