Articles

11/16/1998-- 11/16/1998

Darboux Transformations and solutions for an equation in 2+1 dimensions

Painleve analysis and the singular manifold method are the tools used in this paper to perform a complete study of an equation in 2+1 dimensions. This procedure has allowed us to obtain the Lax pair, Darboux transformation and tau functions in such a way that a plethora of different solutions with solitonic behavior can be constructed iteratively
Pilar Garcia Estevez
06/26/2007-- 04/09/2007

Dark energy, gravitation and supernovae

The discovery of the acceleration of the rate of expansion of the Universe fosters new explorations of the behavior of gravitation theories in the cosmological context. Either the GR framework is valid but a cosmic component with a negative equation of state is dominating the energy--matter contents or the Universe is better described at large by a theory that departs from GR. In this review we address theoretical alternatives that have been explored through supernovae.
Pilar Ruiz-Lapuente
04/14/2010-- 04/14/2010

Scattering Boundary Rigidity in the Presence of a Magnetic Field

It has been shown in \cite{DPSU} that, under some additional assumptions, two simple domains with the same scattering data are equivalent. We show that the simplicity of a region can be read from the metric in the boundary and the scattering data. This lets us extend the results in \cite{DPSU} to regions with the same scattering data, where only one is known apriori to be simple. We will then use this results to resolve a local version of a question by Robert Bryant. That is, we show that a surface of constant curvature can not be modified in a small region while keeping all the curves of some fixed constant geodesic curvatures closed.
Pilar Herreros
08/24/2011-- 08/24/2011

Lens rigidity with trapped geodesics in two dimensions

We consider the scattering and lens rigidity of compact surfaces with boundary that have a trapped geodesic. In particular we show that the flat cylinder and the flat M\"obius strip are determined by their lens data. We also see by example that the flat M\"obius strip is not determined by it's scattering data. We then consider the case of negatively curved cylinders with convex boundary and show that they are lens rigid.
Christopher B. Croke Pilar Herreros
10/11/2012-- 10/11/2012

On Pietsch measures for summing operators and dominated polynomials

We relate the injectivity of the canonical map from $C(B_{E'})$ to $L_p(\mu)$, where $\mu$ is a regular Borel probability measure on the closed unit ball $B_{E'}$ of the dual $E'$ of a Banach space $E$ endowed with the weak* topology, to the existence of injective $p$-summing linear operators/$p$-dominated homogeneous polynomials defined on $E$ having $\mu$ as a Pietsch measure. As an application we fill the gap in the proofs of some results of concerning Pietsch-type factorization of dominated polynomials.
Geraldo Botelho Daniel Pellegrino Pilar Rueda
07/31/2013-- 07/31/2013

A note on extensions of nilpotent algebras of Type 2

We propose the study and description of the structure of complex Lie algebras with nilradical a nilpotent Lie algebra of type 2 by using sl2(C)-representation theory. Our results will be applied to review the classification given in [1] (J. Geometry and Physics, 2011) of the Lie algebras with nilradical the quasiclassical algebra L5;3. A non-Lie algebra has been erroneously included in this classification. The 5-dimensional Lie algebra L5;3 is a free nilpotent algebra of type 2 and it is one of two free nilpotent algebras admitting an invariant metric. According to [, Ok98] quasiclassical algebras let construct consistent Yang-Mills gauge theories.
Pilar Benito Daniel de-la-Concepción
10/04/2013-- 10/04/2013

On the uniqueness of the limit for an asymptotically autonomous semilinear equation on R^N

We consider a parabolic equation of the form u_t=\Delta u +f(u)+h(x,t) in R^N\times (0,\infty), where f in C^1(R) is such that f(0)=0 and f'(0)<0 and h is a suitable function on R^N\times (0,\infty). We show that under certain conditions, each globally defined and nonnegative bounded solution u converges to a single steady state.
Carmen Cortazar Marta Garcia-Huidobro Pilar Herreros
11/19/2013-- 11/19/2013

Weak compactness and strongly summing multilinear operators

Every absolutely summing linear operator is weakly compact. However, for strongly summing multilinear operators and polynomials - one of the most natural extensions of the linear case to the non linear framework - weak compactness does not hold in general. We show that a subclass of the class of strongly summing multilinear operators/polynomials, sharing its main properties such as Grothendieck's Theorem, Pietsch Domination Theorem and Dvoretzky-Rogers Theorem, has even better properties like weak compactness and a natural factorization theorem.
Daniel Pellegrino Pilar Rueda Enrique A. Sanchez-Perez
05/26/2015-- 05/26/2015

Multiplicity results for sign changing bound state solutions of a semilinear equation

In this paper we give conditions on $f$ so that problem $$ \Delta u +f(u)=0,\quad x\in \mathbb{R}^N, N\ge 2, $$ has at least two radial bound state solutions with any prescribed number of zeros, and such that $u(0)$ belongs to a specific subinterval of $(0,\infty)$. This property will allow us to give conditions on $f$ so that this problem has at least any given number of radial solutions having a prescribed number of zeros.
Carmen Cortázar Marta García-Huidobro Pilar Herreros
06/22/2015-- 06/22/2015

Surjectivity of isometries of weighted spaces of holomorphic functions and of Bloch spaces

We examine the surjectivity of isometries between weighted spaces of holomorphic functions. We show that for certain classical weights on the open unit disc all isometries of the weighted space of holomorphic functions, ${ \mathcal H}_{v_o}( \Delta)$, are surjective. Criteria for surjectivity of isometries of ${ \mathcal H}_v(U)$ in terms of a separation condition on points in the image of ${ \mathcal H}_{v_o}(U)$ are also given for $U$ a bounded open set in $\mathbb{C}$. Considering the weight $v(z)= 1-|z|^2$ and the isomorphism $f\mapsto f'$ we are able to show that all isometries of the little Bloch space are surjective.
Christopher Boyd Pilar Rueda


with thanks to arxiv.org/