893 research outputs found

    A Remark on the Spontaneous Symmetry Breaking Mechanism in the Standard Model

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    In this paper we consider the Spontaneous Symmetry Breaking Mechanism (SSBM) in the Standard Model of particles in the unitary gauge. We show that the computation usually presented of this mechanism can be conveniently performed in a slightly different manner. As an outcome, the computation we present can change the interpretation of the SSBM in the Standard Model, in that it decouples the SU(2)-gauge symmetry in the final Lagrangian instead of breaking it.Comment: 16 page

    Noncommutative Yang-Mills-Higgs actions from derivation-based differential calculus

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    Derivations of a noncommutative algebra can be used to construct differential calculi, the so-called derivation-based differential calculi. We apply this framework to a version of the Moyal algebra M{\cal{M}}. We show that the differential calculus, generated by the maximal subalgebra of the derivation algebra of M{\cal{M}} that can be related to infinitesimal symplectomorphisms, gives rise to a natural construction of Yang-Mills-Higgs models on M{\cal{M}} and a natural interpretation of the covariant coordinates as Higgs fields. We also compare in detail the main mathematical properties characterizing the present situation to those specific of two other noncommutative geometries, namely the finite dimensional matrix algebra Mn(C)M_n({\mathbb{C}}) and the algebra of matrix valued functions C(M)Mn(C)C^\infty(M)\otimes M_n({\mathbb{C}}). The UV/IR mixing problem of the resulting Yang-Mills-Higgs models is also discussed.Comment: 23 pages, 2 figures. Improved and enlarged version. Some references have been added and updated. Two subsections and a discussion on the appearence of Higgs fiels in noncommutative gauge theories have been adde

    Introduction

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    Introduction de l'Assemblée générale de Ménestrel – 35e journée d'étude du Réseau des Médiévistes belges de Langue française. Le Moyen Âge dans les (nouveaux) médias. Quelle place pour les médiévistes ? Université de Liège, 7-8 octobre 201

    Syntactic Abstraction of B Models to Generate Tests

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    In a model-based testing approach as well as for the verification of properties, B models provide an interesting solution. However, for industrial applications, the size of their state space often makes them hard to handle. To reduce the amount of states, an abstraction function can be used, often combining state variable elimination and domain abstractions of the remaining variables. This paper complements previous results, based on domain abstraction for test generation, by adding a preliminary syntactic abstraction phase, based on variable elimination. We define a syntactic transformation that suppresses some variables from a B event model, in addition to a method that chooses relevant variables according to a test purpose. We propose two methods to compute an abstraction A of an initial model M. The first one computes A as a simulation of M, and the second one computes A as a bisimulation of M. The abstraction process produces a finite state system. We apply this abstraction computation to a Model Based Testing process.Comment: Tests and Proofs 2010, Malaga : Spain (2010

    Délimiter le Haut-Doubs : entre représentations mentales et limites physiques

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    Le Haut-Doubs constitue depuis longtemps une entité à part en Franche- Comté. Voisin de la Suisse et partie prenante du massif jurassien, son nom évoque d'abord une terre d'altitude. Mais bien au-delà du relief, le Haut-Doubs se définit par un certain espace vécu, par une relation particulière entre ce territoire et ses habitants

    Peace. The Peace of Fexhe

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    The Peace of Fexhe, from its redaction to the end of the Principality of Liège

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    peer reviewedThe Peace of Fexhe has always been seen by the Liegeois as a constitutional treaty of paramount importance as it provided the principality of Liège with a representative assembly. Yet, this text, enacted in 1316, remained in use until the end of the State of Liège. The present article focuses therefore on its history in order to determine the role it actually played in the political life of Liège at the end of the Middle Ages and during the Modern Times. What emerges is that, signed in a context of tension, the Peace of Fexhe really was a compromise signed between two parties exhausted by famine, not the victory of one over the other. Even though the treaty seems to record several claims of the opponents to the prince-bishop Adolphe de La Marck, it really is the latter who, in spite of what numerous historians believed, continued to direct the political game of Liège. Indeed, his arbitrators managed to counter the claims of their opponents through the insertion of clauses preventing any real upheaval within the principality. For Adolphe, this treaty is therefore a break in his quest for a total sovereignty. Following him, the prince-bishops of Liège strove in defence of their power, contravening if need be the text of 1316. The Liégeois appeared to us to have been perfectly aware of the limits of the Peace of Fexhe but they endeavoured to gloss over these in order to make the text an absolute reference in the domain of political claims and a revered rallying symbol. Then, it will be through the constant reminder of this treaty that various political claims arose, making it de facto the source of the “Liegian constitution”. Afterwards, the Liegeois had recourse to the Peace of Fexhe in order to legitimate their political options. However, it was absolutely not a general rule since several politicians close to the people, such as Thierry de Perwez or Raes de Heers did not make use of the text. On the contrary, it was within more “cultivated” circles, such as the municipal magistrates and the burgomasters, that the text was the less rarely used, whether it be at the time of the promulgation of the decisions of the Council of Trente or at the eve of the Liegian Revolution. Moreover, it is by its almost uninterrupted presence in the Liegian politics that the Peace of Fexhe asks the question of the administration of law in the principality. In spite of a common objective, punishing the abuse of power of the episcopal officers, it was in opposition over the question of the procedure with the Peaces of the XXII . Yet the Court of the XXII considered itself to be in charge of the defence of the Peace of Fexhe. Similarly, the capitulations of the prince-bishops swore to the respect of the text and court without fear of a contradiction that no one seemed to have wanted to highlight. This shows how deep it was rooted in the Liegian legal culture, even though the real action of the Peace of Fexhe through the centuries left few traces. In conclusion, the Peace of Fexhe owes its prestige to its recuperation by different political forces that used it as a battle flag, adapting it, contradicting it sometimes, to their claims. Thus, event though its exact stipulations were forgotten as soon as the end of the 16th century and it was then progressively completed, it survived in the imagination and built up its prestige on the additional meaning its utilisations provided it with, for, in Liège, who defends Fexhe defends the good right.La Paix de Fexhe a toujours revêtu aux yeux des Liégeois l'apparence d'un traité constitutionnel de première importance qui dotait la principauté de Liège d'une assemblée représentative. Or, ce texte, édicté en 1316, est resté en vigueur jusqu'à la fin de l'État liégeois. Le présent article se concentre donc sur son histoire afin de déterminer le rôle qu'il joua effectivement dans la vie politique liégeoise de la fin du Moyen Âge et des Temps modernes. Il en ressort que, signée dans un contexte de tensions, la Paix de Fexhe est bien un compromis signés entre deux partis épuisés par la famine et non la victoire de l’un sur l'autre. Même si elle semble enregistrer plusieurs exigences des opposants au prince-évêque Adolphe de La Marck, c'est bien ce dernier qui, malgré ce qu’ont pu croire nombre d’historiens, continue à diriger réellement le jeu politique liégeois. En effet, ses arbitres sont parvenus à contrer les revendications de leurs adversaires par l’insertion de clauses empêchant un réel bouleversement au sein de la principauté. Pour Adolphe, ce traité est donc une pause dans sa quête d’une souveraineté totale. À sa suite, les princes-évêques de Liège œuvreront tous à la défense de leur pouvoir, contrevenant au besoin au texte de 1316. Les Liégeois nous semblent être parfaitement conscients des limites de la Paix de Fexhe mais ils vont s’efforcer de les taire afin de faire de ce texte une référence absolue dans le domaine des revendications politiques et un signe révéré de ralliement. Ce sera ensuite d’un rappel constant de ce traité que procèderont les diverses revendications politiques, en faisant de facto la source de la « constitution liégeoise ». Par la suite, les Liégeois recourront ponctuellement à la Paix de Fexhe pour légitimer leurs options politiques. Cependant, il ne s’agit absolument pas là d’une règle générale puisque des hommes politiques proches du peuple tels Thierry de Perwez ou Raes de Heers ne font pas appel à ce texte. Au contraire, c’est dans les cercles plus « cultivés », tels les échevins ou les bourgmestres, que ce texte est le moins rarement utilisé, que ce soit lors de la promulgation des décisions du Concile de Trente ou à la veille de la Révolution liégeoise. D’autre part, c’est par sa présence presque ininterrompue dans la politique liégeoise que la Paix de Fexhe pose la question de l’exercice de la loi dans la principauté. Malgré un objectif commun, châtier les abus de pouvoir des officiers épiscopaux, elle est en opposition sur la question de la procédure avec les Paix des XXII. Or le Tribunal des XXII se considère comme chargé de la défense de la Paix de Fexhe. De même les capitulations des princes-évêques jurent le respect de ces texte et tribunal sans craindre une contradiction que personne ne semble avoir voulu mettre en évidence. Cela témoigne donc d’un enracinement profond dans la culture juridique liégeoise, alors même que l’action réelle de la Paix de Fexhe au fil des siècles n’a laissé que peu de traces. En conclusion, la Paix de Fexhe doit son prestige à sa récupération par différentes forces politiques qui s’en servent tel un étendard, l’adaptant, et la contredisant parfois, à leurs revendications. Ainsi, alors même que ses stipulations exactes sont oubliées dès la fin du XIVe siècle et qu’elle est progressivement complétée, elle survit dans l’imaginaire et bâtit son prestige sur le surcroît de sens que lui donne son utilisation, car, à Liège, qui défend Fexhe défend le bon droit

    The Footmen die but they never surrender!

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