Articles
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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
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