Now showing items 1-20 of 22

• #### Axiomàtica dels nombres reals ﻿

(Universitat Politècnica de Catalunya, 2013-06)
Bachelor thesis
Open Access
L'objectiu d'aquest treball és estudiar les propietats del conjunt de nombres reals, començant per una construcció d'aquest conjunt a través de classes d'equivalència de successions de Cauchy. Posteriorment, es prendrà ...
• #### Constraint algorithm for k-presymplectic hamiltonian systems: application to singular field theories ﻿

(World Scientific and Engineering Academy and Society (WSEAS), 2009-08-01)
Article
Open Access
The k-symplectic formulation of ﬁeld theories is specially simple, since only tangent and cotangent bundles are needed in its description. Its deﬁning elements show a close relationship with those in the symplectic formulation ...
• #### Constraint algorithm for singular field theories in the k-cosymplectic framework ﻿

(American Institute of Mathematical Sciences, 2020-03-15)
Article
Open Access
The aim of this paper is to develop a constraint algorithm for singular classical field theories in the framework of k-cosymplectic geometry. Since these field theories are singular, we need to introduce the notion of ...
• #### Ferroelectrics as smart mechanical materials ﻿

(2017-07-21)
Article
Open Access
The mechanical properties of materials are insensitive to space inversion, even when they are crystallographically asymmetric. In practice, this means that turning a piezoelectric crystal upside down or switching the ...
• #### Galois: entre els radicals ﻿

(2012-10-03)
Audiovisual
Open Access
• #### Generic Galois extensions for SL_2(F_5) over Q ﻿

(Mathematical Publishing, 2007)
Article
Open Access
Let $G_n$ be a double cover of either the alternating group $A_n$ or the symmetric group $S_n$, and let $G_{n-1}$ be the corresponding double cover of $A_{n-1}$ or $S_{n-1}$. For every odd $n\geq 3$ and every field $k$ of ...
• #### Griffiths variational multisymplectic formulation for Lovelock gravity ﻿

(2020-08-24)
Article
Restricted access - publisher's policy
This work is mainly devoted to constructing a multisymplectic description of Lovelock’s gravity, which is an extension of General Relativity. We establish the Griffiths variational problem for the Lovelock Lagrangian, ...
• #### Grupos de Galois lineales provenientes de la geometría ﻿

(2013-03-06)
Audiovisual
Open Access
• #### Hamilton-Jacobi theory in multisymplectic classical field theories ﻿

(2017-09-01)
Article
Open Access
The geometric framework for the Hamilton-Jacobi theory developed in the studies of Carinena et al. [Int. J. Geom. Methods Mod. Phys. 3(7), 1417-1458 (2006)], Carinena et al. [Int. J. Geom. Methods Mod. Phys. 13(2), 1650017 ...
• #### Higher-order Cartan symmetries in k-symplectic field theory ﻿

(2008-04-30)
Article
Open Access
For k-symplectic Hamiltonian field theories, we study infinitesimal transformations generated by certain kinds of vector fields which are not Noether symmetries, but which allow us to obtain conservation laws by means ...
• #### Hopf Galois structures on symmetric and alternating extensions ﻿

(2018)
Article
Open Access
By using a recent theorem by Koch, Kohl, Truman and Underwood on normality, we determine that some types of Hopf Galois structures do not occur on Galois extensions with Galois group isomorphic to alternating or symmetric ...
• #### Induced Hopf Galois structures ﻿

(2016-07-01)
Article
Open Access
For a ¿nite Galois extension K/k and an intermediate ¿eld F such that Gal(K/F)has a normal complement in Gal(K/k), we construct and characterize Hopf Galois structures on K/k which are induced by a pair of Hopf Galois ...
• #### Lectura de la memòria sobre la resolubilitat de les equacions per radicals ﻿

(2013-03-06)
Audiovisual
Open Access
• #### Multisymplectic Lagrangian and Hamiltonian formalisms of classical field theories ﻿

(2009)
Article
Open Access
This review paper is devoted to presenting the standard multisymplectic formulation for describing geometrically classical field theories, both the regular and singular cases. First, the main features of the Lagrangian ...
• #### Multisymplectic unified formalism for Einstein-Hilbert gravity ﻿

(2018-03-01)
Article
Open Access
We present a covariant multisymplectic formulation for the Einstein-Hilbert model of General Relativity. As it is described by a second-order singular Lagrangian, this is a gauge field theory with constraints. The use of ...
• #### New multisymplectic approach to the Metric-Affine (Einstein-Palatini) action for gravity ﻿

(American Institute of Mathematical Sciences, 2019-09-01)
Article
Open Access
We present a covariant multisymplectic formulation for the Einstein-Palatini (or Metric-Affine) model of General Relativity (without energy-matter sources). As it is described by a first-order affine Lagrangian (in the ...
• #### Non-isomorphic Hopf Galois structures with isomorphic underlying Hopf algebras ﻿

(2014-10-30)
Article
Restricted access - publisher's policy
We give a degree 8 non-normal separable extension having two non-isomorphic Hopf Galois structures with isomorphic underlying Hopf algebras.
• #### On the k-symplectic, k-cosymplectic and multisymplectic formalisms of classical field theories ﻿

(2007-05-31)
Article
Open Access
The objective of this work is twofold: First, we analyze the relation between the kcosymplectic and the k-symplectic Hamiltonian and Lagrangian formalisms in classical field theories. In particular, we prove the equivalence ...
• #### El Problema invers de la teoria de Galois ﻿

(2013-03-06)
Audiovisual
Open Access
• #### Remarks on multisymplectic reduction ﻿

(2018-06-01)
Article
Open Access
The problem of reduction of multisymplectic manifolds by the action of Lie groups is stated and discussed, as a previous step to give a fully covariant scheme of reduction for classical field theories with symmetries.