Results for "Juan Carlos Pardo"

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Fluctuations of stable processes and exponential functionals of hypergeometric Levy processesDec 03 2010We study the distribution and various properties of exponential functionals of hypergeometric Levy processes. We derive an explicit formula for the Mellin transform of the exponential functional and give both convergent and asymptotic series expansions ... More
Asymptotic behaviour near extinction of continuous state branching processesAug 02 2013In this note, we study the asymptotic behaviour near extinction of (sub-) critical continuous state branching processes. In particular, we establish an analogue of Khintchin's law of the iterated logarithm near extinction time for a continuous state branching ... More
Continuous state branching processes in random environment: The Brownian caseJun 30 2015Jun 16 2016We consider continuous state branching processes that are perturbed by a Brownian motion. These processes are constructed as the unique strong solution of a stochastic differential equation. The long-term extinction and explosion behaviours are studied. ... More
Extinction time of CB-processes with competition in a Lévy random environmentJan 14 2018Jan 25 2018In this paper, we are interested on the extinction time of continuous state branching processes with competition in a L\'evy random environment. In particular we prove, under the so-called Grey's condition together with the assumption that the L\'evy ... More
Cut-off phenomenon for Ornstein-Uhlenbeck processes driven by Lévy processesDec 18 2018In this paper, we study the cut-off phenomenon of $d$-dimensional Ornstein-Uhlenbeck processes which are driven by L\'evy processes under the total variation distance. To be more precise, we prove the abrupt convergence under the total variation distance ... More
Extinction rate of continuous state branching processes in critical Lévy environmentsMar 14 2019We study the speed of extinction of continuous state branching processes in a L\'evy environment, where the associated L\'evy process oscillates. Assuming that the L\'evy process satisfies the Spitzer's condition and the existence of some exponential ... More
The Wright-Fisher model with efficiencyFeb 20 2019In populations consisting of individuals of two types competing for the same resources, the following natural question arises, does being more efficient (for instance needing less resources to reproduce) provides a selective advantage or disadvantage? ... More
An optimal stopping problem for fragmentation processesJan 26 2011In this article we consider a toy example of an optimal stopping problem driven by fragmentation processes. We show that one can work with the concept of stopping lines to formulate the notion of an optimal stopping problem and moreover, to reduce it ... More
Asymptotic behaviour of exponential functionals of Lévy processes with applications to random processes in random environmentJan 14 2016Jun 24 2016Let $\xi=(\xi_t, t\ge 0)$ be a real-valued L\'evy process and define its associated exponential functional as follows \[ I_t(\xi):=\int_0^t \exp\{-\xi_s\}{\rm d} s, \qquad t\ge 0. \] Motivated by important applications to stochastic processes in random ... More
On the genealogy on conditioned stable Lévy forestJun 18 2007We give a realization of the stable L\'evy forest of a given size conditioned by its mass from the path of the unconditioned forest. Then, we prove an invariance principle for this conditioned forest by considering $k$ independent Galton-Watson trees ... More
Meromorphic Levy processes and their fluctuation identitiesApr 26 2010Apr 09 2011The last couple of years has seen a remarkable number of new, explicit examples of the Wiener-Hopf factorization for Levy processes where previously there had been very few. We mention in particular the many cases of spectrally negative Levy processes, ... More
On the density of exponential functionals of Lévy processesJul 19 2011In this paper, we study the existence of the density associated to the exponential functional of the L\'evy process $\xi$, \[ I_{\ee_q}:=\int_0^{\ee_q} e^{\xi_s} \, \mathrm{d}s, \] where $\ee_q$ is an independent exponential r.v. with parameter $q\geq ... More
Lévy insurance risk processes with parisian type severity of debtJul 26 2015In this article, we introduce a new definition of bankruptcy for a spectrally negative L\'evy insurance risk process. More precisely, we study the Gerber-Shiu distribution for a ruin model where at each time the surplus goes negative, an independent negative ... More
Total internal and external lengths of the Bolthausen-Sznitman coalescentFeb 06 2013In this paper, we study a weak law of large numbers for the total internal length of the Bolthausen-Szmitman coalescent. As a consequence, we obtain the weak limit law of the centered and rescaled total external length. The latter extends results obtained ... More
Branching processes with interactions: the subcritical cooperative regimeApr 13 2017Oct 11 2018In this paper, we introduce a particular family of processes with values on the nonnegative integers that model the dynamics of populations where individuals are allow to have different types of inter- actions. The types of interactions that we consider ... More
A model specification test for the variance function in nonparametric regressionJul 23 2018The problem of testing for the parametric form of the conditional variance is considered in a fully nonparametric regression model. A test statistic based on a weighted $L_2$-distance between the empirical characteristic functions of residuals constructed ... More
Recurrent extensions of real-valued self-similar Markov processesAug 01 2018Let $X=(X_t, t\geq 0)$ be a self-similar Markov process taking values in $\mathbb{R}$ such that the state 0 is a trap. In this paper, we present a necessary and sufficient condition for the existence of a self-similar recurrent extension of $X$ that leaves ... More
Double hypergeometric Lévy processes and self-similarityApr 12 2019Motivated by a recent paper of Budd, where a new family of positive self-similar Markov processes associated to stable processes appears, we introduce a new family of L\'evy processes, called the double hypergeometric class, whose Wiener-Hopf factorisation ... More
Some explicit identities associated with positive self-similar Markov processesAug 17 2007We consider some special classes of L\'evy processes with no gaussian component whose L\'evy measure is of the type $\pi(dx)=e^{\gamma x}\nu(e^x-1) dx$, where $\nu$ is the density of the stable L\'evy measure and $\gamma$ is a positive parameter which ... More
Fluctuation theory and exit systems for positive self-similar Markov processesDec 13 2008Dec 07 2012For a positive self-similar Markov process, X, we construct a local time for the random set, $\Theta$, of times where the process reaches its past supremum. Using this local time we describe an exit system for the excursions of X out of its past supremum. ... More
On the Free Fractional Wishart ProcessApr 20 2015Oct 07 2016We investigate the process of eigenvalues of a fractional Wishart process defined as N=B*B, where B is a matrix fractional Brownian motion recently studied by Nualart and P\'erez-Abreu. Using stochastic calculus with respect to the Young integral we show ... More
The excursion measure away from zero for spectrally negative Lévy processesJul 18 2015We provide a description of the excursion measure from a point for a spectrally negative L\'evy process. The description is based in two main ingredients. The first is building a spectrally negative L\'evy process conditioned to avoid zero and the study ... More
A Wiener-Hopf Type Factorization for the Exponential Functional of Levy ProcessesApr 30 2011Feb 07 2012For a L\'evy process $\xi=(\xi_t)_{t\geq0}$ drifting to $-\infty$, we define the so-called exponential functional as follows \[{\rm{I}}_{\xi}=\int_0^{\infty}e^{\xi_t} dt.\] Under mild conditions on $\xi$, we show that the following factorization of exponential ... More
Convergence of the empirical spectral distribution of Gaussian matrix-valued processesJan 07 2018For a given normalized Gaussian symmetric matrix-valued process $Y^{(n)}$, we consider the process of its eigenvalues $\{(\lambda_{1}^{(n)}(t),\dots, \lambda_{n}^{(n)}(t)); t\ge 0\}$ as well as its corresponding process of empirical spectral measures ... More
Backbone decomposition of multitype superprocessesMar 26 2018In this paper, we provide a construction of the so-called backbone decomposition for multitype supercritical superprocesses. While backbone decompositions are fairly well-known for both continuous-state branching processes and superprocesses in the one-type ... More
On the Theory of Self-Adjoint Extensions of the Laplace-Beltrami Operator, Quadratic Forms and SymmetryAug 09 2013Sep 17 2013The main objective of this dissertation is to analyse thoroughly the construction of self-adjoint extensions of the Laplace-Beltrami operator defined on a compact Riemannian manifold with boundary and the role that quadratic forms play to describe them. ... More
The (p,q)-extremal problem and the fractional chromatic number of Kneser hypergraphsAug 14 2014The problem of computing the chromatic number of Kneser hypergraphs has been extensively studied over the last 40 years and the fractional version of the chromatic number of Kneser hypergraphs is only solved for particular cases. The \emph{$(p,q)$-extremal ... More
The hitting time of zero for a stable processDec 20 2012Mar 10 2014For any two-sided jumping $\alpha$-stable process, where $1 < \alpha < 2$, we find an explicit identity for the law of the first hitting time of the origin. This complements existing work in the symmetric case and the spectrally one-sided case; cf. Yano-Yano-Yor ... More
Ab initio study of nontrivial topological phases in corundum structured $($M$_2$O$_3)/($Al$_2$O$_3)_5$ multilayersJul 31 2015Oct 26 2015\textit{Ab initio} calculations have been performed on hexagonal layers of M$_2$O$_3$ (M being several transition metals of the $5d$ series) sandwiched by a band insulator such as Al$_2$O$_3$ that provides the honeycomb lattice where the $5d$ electrons ... More
Numerical Solutions of the spectral problem for arbitrary self-adjoint extensions of the 1D Schroedinger equationMar 29 2011Mar 03 2014A numerical algorithm to solve the spectral problem for arbitrary self-adjoint extensions of 1D regular Schroedinger operators is presented. It is shown that the set of all self-adjoint extensions of 1D regular Schroedinger operators is in one-to-one ... More
The upper envelope of positive self-similar Markov processesMar 02 2007We establish integral tests and laws of the iterated logarithm at 0 and at $+\infty$, for the upper envelope of positive self-similar Markov processes. Our arguments are based on the Lamperti representation, time reversal arguments and on the study of ... More
Approximate linear minimum variance filters for continuous-discrete state space models: convergence and practical algorithmsJul 25 2012Dec 17 2013In this paper, approximate Linear Minimum Variance (LMV) filters for continuous-discrete state space models are introduced. The filters are obtained by means of a recursive approximation to the predictions for the first two moments of the state equation. ... More
The cohomology structure of string algebrasOct 05 2004We show that the graded commutative ring structure of the Hochschild cohomology HH*(A) is trivial in case A is a triangular quadratic string algebra. Moreover, in case A isgentle, the Lie algebra structure on HH*(A) is also trivial.
Primordial Black Holes in non-linear perturbation theoryOct 09 2009This thesis begins with a study of the origin of cosmological fluctuations with special attention to those cases in which the non-Gaussian correlation functions are large. The analysis shows that perturbations from an almost massless auxiliary field generically ... More
Quantum modulation against electromagnetic interferenceNov 26 2014Periodic signals in electrical and electronic equipment can cause interference in nearby devices. Randomized modulation of those signals spreads their energy through the frequency spectrum and can help to mitigate electromagnetic interference problems. ... More
Photon exchange and correlations transfer in atom-atom entanglement dynamicsNov 17 2008We analyze the entanglement dynamics of a system composed by a pair of neutral two-level atoms that are initially entangled, and the electromagnetic field, initially in the vacuum state, within the formalism of perturbative quantum field theory up to ... More
Entanglement swapping between spacelike separated atomsJul 17 2008Oct 15 2008We show a mechanism that projects a pair of neutral two-level atoms from an initially uncorrelated state to a maximally entangled state while they remain spacelike separated. The atoms begin both excited in a common electromagnetic vacuum, and the radiation ... More
Time-reversal symmetry violation in several Lepton-Flavor-Violating processesApr 20 2015Sep 22 2015We compute a T-odd triple vector correlation for the $\mu\rightarrow e\gamma $ decay and the $\mu\rightarrow e$ conversion process. We find simple results in terms of the CP violating phases of the effective Hamiltonians. Then we focus on the minimal ... More
Supergravity description of field theories on curved manifolds and a no go theoremJul 03 2000Jul 08 2000In the first part of this paper we find supergravity solutions corresponding to branes on worldvolumes of the form $R^d \times \Sigma$ where $\Sigma$ is a Riemann surface. These theories arise when we wrap branes on holomorphic Riemann surfaces inside ... More
BasisGen: automatic generation of operator basesJan 11 2019BasisGen is a Python package for the automatic generation of bases of operators in effective field theories. It accepts any semisimple symmetry group and fields in any of its finite dimensional irreducible representations. It takes into account integration ... More
The strong convexity spectra of gridsMar 08 2017Let $D$ be a connected oriented graph. A set $S \subseteq V(D)$ is convex in $D$ if, for every pair of vertices $x, y \in S$, the vertex set of every $xy$-geodesic, ($xy$ shortest directed path) and every $yx$-geodesic in $D$ is contained in $S$. The ... More
Integration on the Hilbert CubeMay 03 2017The aim of this article is to generalize the Lebesgue integration theory to $\mathbb{R}^{\mathbb{N}}$ within a preliminary measure theory, just as an extension of finite dimensional Lebesgue integral. We'll state an elementary but rigorous integration ... More
Five-body choreography on the algebraic lemniscate is a potential motionAug 21 2018Jan 24 2019In a remarkable paper of 2003 by Fujiwara et al. \cite{Fujiwara2003}, a figure-eight three-body choreography on the algebraic lemniscate by Bernoulli was discovered. Such a choreography was found to be driven by the action of a pairwise potential $ V(r_{ij}) ... More
Generation of atom-atom correlations inside and outside the mutual light coneApr 29 2008Dec 11 2008We analyze whether a pair of neutral two level atoms can become entangled in a finite time while they remain causally disconnected. The interaction with the e. m. field is treated perturbatively in the electric dipole approximation. We start from an initial ... More
Dual mixed volumes and isosystolic inequalitiesAug 30 2004The theory of dual mixed volumes is extended to star bodies in cotangent bundles and is used to prove several isosystolic inequalities for Hamiltonian systems and Finsler metrics.
Dual spheres have the same girthAug 30 2004Symplectic and Finsler geometry are used to settle a conjecture of Sch\"affer stating that the girth of a normed space--the infimum of the lengths of all closed, rectifiable, centrally symmetric curves on its unit sphere--equals the girth of its dual. ... More
Simplified formulas for the mean and variance of linear stochastic differential equationsJul 20 2012Dec 17 2013Explicit formulas for the mean and variance of linear stochastic differential equations are derived in terms of an exponential matrix. This result improved a previous one by means of which the mean and variance are expressed in terms of a linear combination ... More
Asymmetry in Hilbert's fourth problemJan 11 2013In the asymmetric setting, Hilbert's fourth problem asks to construct and study all (non-reversible) projective Finsler metrics: Finsler metrics defined on open, convex subsets of real projective $n$-space for which geodesics lie on projective lines. ... More
On Self-adjoint extensions and symmetries in Quantum MechanicsFeb 22 2014Sep 23 2014Given a unitary representation of a Lie group $G$ on a Hilbert space $\mathcal{H}$, we develop the theory of $G$-invariant self-adjoint extensions of symmetric operators both using von Neumann's theorem and the theory of quadratic forms. We also analyze ... More
Generalised Potential Functions in Differential Geometry and Information GeometryApr 27 2018Feb 01 2019Potential functions can be used as generating potentials of relevant geometric structures for a Riemannian manifold such as the Riemannian metric and affine connections. We study wether this procedure can also be applied to tensors of rank four and find ... More
Self-adjoint extensions of the Laplace-Beltrami operator and unitaries at the boundaryAug 02 2013We construct in this article a class of closed semi-bounded quadratic forms on the space of square integrable functions over a smooth Riemannian manifold with smooth boundary. Each of these quadratic forms specifies a semi-bounded self-adjoint extension ... More
Thermal tuners on a Silicon Nitride platformApr 11 2016In this paper, the design trade-offs for the implementation of small footprint thermal tuners on silicon nitride are presented, and explored through measurements and supporting simulations of a photonic chip based on Mach-Zehnder Interferometers. Firstly, ... More
Excess velocity of magnetic domain walls close to the depinning fieldAug 11 2017Jan 23 2018Magnetic field driven domain wall velocities in [Co/Ni] based multilayers thin films have been measured using polar magneto-optic Kerr effect microscopy. The low field results are shown to be consistent with the universal creep regime of domain wall motion, ... More
The lower envelope of positive self-similar Markov processesJan 09 2006We establish integral tests and laws of the iterated logarithm for the lower envelope of positive self-similar Markov processes at 0 and $+\infty$. Our proofs are based on the Lamperti representation and time reversal arguments. These results extend laws ... More
Geometric invariants of fanning curvesFeb 23 2005We study the geometry of an important class of generic curves in the Grassmannian manifolds of $n$-dimensional subspaces and Lagrangian subspaces of $R^{2n}$ under the action of the linear and linear symplectic group.
Stationary scalar configurations around extremal charged black holesMar 10 2013We consider the minimally coupled Klein-Gordon equation for a charged, massive scalar field in the non-extremal Reissner-Nordstr\"om background. Performing a frequency domain analysis, using a continued fraction method, we compute the frequencies \omega ... More
Superatomic Boolean algebras constructed from strongly unbounded functionsApr 27 2010Using Koszmider's strongly unbounded functions, we show the following consistency result: Suppose that $\kappa,\lambda$ are infinite cardinals such that $\kappa^{+++} \leq \lambda$, $\kappa^{<\kappa}=\kappa$ and $2^{\kappa}= \kappa^+$, and $\eta$ is an ... More
Biquadrates and Elliptic CurvesMar 12 2012The elliptic curve y^2= x^3-Nx where N=m^4+n^4 has rank at least 2 over Q(m,n). When N can be written in two different ways as sum of two fourth powers, then we prove that the rank is at least 4.
Elliptic curves induced by Diophantine triplesDec 06 2017Feb 22 2018Given a Diophantine triple $\{c_1(t),c_2(t),c_3(t)\}$, the elliptic curve over Q(t) induced by this triple, i.e. $y^2=(c_1(t) x+1) (c_2(t) x+1) (c_3(t) x+1)$, can have as torsion group one of the non-cyclic groups in Mazur's theorem, i.e. Z/2Z x Z/2Z, ... More
Elliptic curves with torsion group Z/8Z or Z/2Z x Z/6ZMay 31 2013We show the existence of families of elliptic curves over Q whose generic rank is at least 2 for the torsion groups Z/8Z and Z/2Z x Z/6Z. Also in both cases we prove the existence of infinitely many elliptic curves, which are parameterized by the points ... More
Locally conformal symplectic nilmanifolds with no locally conformal Kähler metricsJul 21 2014We obtain an example of a compact locally conformal symplectic nilmanifold which admits no locally conformal K\"ahler metrics. This gives a new positive answer to a question raised by L. Ornea and M. Verbitsky.
A nonlinear interpolatory reconstruction operator on non uniform gridsNov 26 2018This paper is devoted to introduce the non linear reconstruction operator PPH on non uniform grids. We define this operator and we study its main properties such as reproduction of polynomials of second degree, approximation order and conditions for convexity ... More
Who is the best connected EC researcher? Centrality analysis of the complex network of authors in evolutionary computationAug 15 2007Co-authorship graphs (that is, the graph of authors linked by co-authorship of papers) are complex networks, which expresses the dynamics of a complex system. Only recently its study has started to draw interest from the EC community, the first paper ... More
Towards the large N limit of pure N=1 super Yang MillsAug 01 2000Sep 26 2000We find the gravity solution corresponding to a large number of NS or D fivebranes wrapped on a two sphere so that we have pure ${\cal N}=1$ super Yang-Mills in the IR. The supergravity solution is smooth, it shows confinement and it breaks the $U(1)_R$ ... More
Modular Invariance Faces Precision Neutrino DataJul 03 2018Sep 25 2018We analyze a modular invariant model of lepton masses, with neutrino masses originating either from the Weinberg operator or from the seesaw. The constraint provided by modular invariance is so strong that neutrino mass ratios, lepton mixing angles and ... More
A consistency result on long cardinal sequencesJan 25 2019Feb 18 2019For any regular cardinal $\kappa$ and ordinal $\eta<\kappa^{++}$ it is consistent that $2^{\kappa}$ is as large as you wish, and every function $f:\eta \to [\kappa,2^{\kappa}]\cap Card$ with $f(\alpha)=\kappa$ for $cf(\alpha)<\kappa$ is the cardinal sequence ... More
Recognizing projections of rational curvesMar 24 2016Given two rational, properly parametrized space curves ${\mathcal C}_1$ and ${\mathcal C}_2$, where $\CCC_2$ is contained in some plane $\Pi$, we provide an algorithm to check whether or not there exist perspective or parallel projections mapping $\CCC_1$ ... More
Hochschild Cohomology and the Derived Class of M-Cluster Tilted Algebras of Type AJan 19 2012We classify all finite dimensional algebras which are derived equivalent to m-cluster tilted algebras of type A.
A Knowledge Representation Perspective on Activity TheoryNov 14 2018Intelligent technologies, in particular systems to promote health and well-being, are inherently centered around the human being, and they need to interrelate with human activities at their core. While social sciences provide angles to study such activities, ... More
Fundamental groups and presentations of algebrasMay 07 2004May 03 2005In this note, we investigate how different fundamental groups of presentations of a fixed algebra $A$ can be. For finitely many finitely presented groups $G_i$, we construct an algebra $A$ such that all $G_i$ appear as fundamental groups of presentations ... More
Non-local Lagrangians from Renormalons and Analyzable FunctionsFeb 15 2019We embed in a generalized Borel procedure the notion of renormalization and renormalons. While there are several efforts in literature to have a semi-classical understanding of the renormalons, here we argue that this is not the fundamental issue and ... More
Optimal Linear Instrumental Variables ApproximationsMay 08 2018Dec 11 2018Ordinary least squares provides the optimal linear approximation to the true regression function. This paper investigates the Instrumental Variables (IV) version of this problem. The resulting parameter is called the Optimal Linear IV Approximation (OLIVA). ... More
Resummation and renormalons in a general Quantum Field TheoryFeb 16 2018Apr 25 2018We generalize the concept of Borel resummability and renormalons to a quantum field theory with an arbitrary number of fields and couplings, starting from the known notion based on the running coupling constants. An approach to identify the renormalons ... More
The Complex Network of Evolutionary Computation Authors: an Initial StudyJul 27 2005Jul 28 2005EC paper authors form a complex network of co-authorship which is, by itself, a example of an evolving system with its own rules, concept of fitness, and patterns of attachment. In this paper we explore the network of authors of evolutionary computation ... More
High Tc Superconductors: New Insights from Angle-Resolved PhotoemissionSep 10 1997Recent angle-resolved photoemission (ARPES) studies of the high Tc superconductors are reviewed. Amongst the topics discussed are: the spectral function interpretation of ARPES data and sum rules; studies of the momentum distribution and the Fermi surface ... More
Theta-duality on Prym varieties and a Torelli TheoremOct 03 2010Jul 29 2011Let p:C' -> C be an unramified double covering of irreducible smooth curves and let P be the attached Prym variety. We prove the schematic theta-dual equalities in the Prym variety T(C')=V^2 and T(V^2)=C', where V^2 is the Brill-Noether locus of P associated ... More
The Hamilton-Jacobi equation on Lie affgebroidsNov 03 2005The Hamilton-Jacobi equation for a Hamiltonian section on a Lie affgebroid is introduced and some examples are discussed.
Range-based argumentation semantics as 2-valued modelsFeb 29 2016Characterizations of semi-stable and stage extensions in terms of 2-valued logical models are presented. To this end, the so-called GL-supported and GL-stage models are defined. These two classes of logical models are logic programming counterparts of ... More
On symplectic lifts of actions for complete Lagrangian fibrationsOct 12 2018In this note we discuss symplectic lifts of actions for a complete Lagrangian fibration. Firstly, we describe the symplectic cotangent lifts of a G-action on a manifold Q in terms of 1-cocycles in the cohomology of G induced by the action with values ... More
Low energy nodal solutions to the Yamabe equationJul 16 2018Given an isoparametric function $f$ on the $n$-dimensional sphere, we consider the space of functions $w\circ f$ to reduce the Yamabe equation on the round sphere into a singular ODE on $w$ in the interval $[0,\pi]$, of the form $w" + (h(r)/\sin r)w'+\lambda(\vert ... More
Cardinal sequences of LCS spaces under GCHDec 04 2007We give full characterization of the sequences of regular cardinals that may arise as cardinal sequences of locally compact scattered spaces under GCH. The proofs are based on constructions of universal locally compact scattered spaces.
On the Komar Energy and the Generalized Smarr Formula for a Charged Black Hole of Noncommutative GeometryOct 09 2012We calculate the Komar energy $E$ for a charged black hole inspired by noncommutative geometry and identify the total mass ($M_{0}$) by considering the asymptotic limit. We also found the generalized Smarr formula, which shows a deformation from the well ... More
On cardinal sequences of length < omega3Oct 25 2018We prove the following consistency result for cardinal sequences of length $< \om_3$: if GCH holds and $\la \geq \om_2$ is a regular cardinal, then in some cardinal-preserving generic extension $2^{\om} = \la$ and for every ordinal $\eta < \om_3$ and ... More
Quantile-Regression Inference With Adaptive Control of SizeJul 18 2018Regression quantiles have asymptotic variances that depend on the conditional densities of the response variable given regressors. This paper develops a new estimate of the asymptotic variance of regression quantiles that leads any resulting Wald-type ... More
Multiplicity of nodal solutions to the Yamabe problemDec 07 2016Jul 18 2017Given a compact Riemannian manifold $(M,g)$ without boundary of dimension $m\geq 3$ and under some symmetry assumptions, we establish existence of one positive and multiple nodal solutions to the Yamabe-type equation $$-div_{g}(a\nabla u)+bu=c|u|^{2^{\ast}-2}u\quad ... More
On locally conformal symplectic manifolds of the first kindOct 16 2015Mar 21 2016We present some examples of locally conformal symplectic structures of the first kind on compact nilmanifolds which do not admit Vaisman metrics. One of these examples does not admit locally conformal K\"ahler metrics and all the structures come from ... More
Representation of non-semibounded quadratic forms and orthogonal additivitySep 10 2018In this article we give a representation theorem for non-semibounded Hermitean quadratic forms in terms of a (non-semibounded) self-adjoint operator. The main assumptions are closability of the Hermitean quadratic form, the direct integral structure of ... More
Atmospheric monitoring in the mm and sub-mm bands for cosmological observations: CASPER2Nov 13 2012Cosmological observations from ground at millimetre and sub-millimetre wavelengths are affected by atmospheric absorption and consequent emission. The low and high frequency (sky noise) fluctuations of atmospheric performance imply careful observational ... More
The diachromatic number of digraphsDec 01 2017Apr 06 2018We consider the extension to directed graphs of the concept of achromatic number in terms of acyclic vertex colorings. The achromatic number have been intensely studied since it was introduced by Harary, Hedetniemi and Prins in 1967. The dichromatic number ... More
Limits of quotients of real polynomial functions of three variablesMay 15 2015Apr 29 2016An algorithm for computing the limit of a quotient of bivariate real analytic functions has been developed by one of the authors in (Limits of quotients of bivariate real analytic functions, Journal of Symbolic Computation, 50, 2013, 197 207). In this ... More
On transversal and 2-packing numbers in uniform linear systemsMar 19 2019A linear system is a pair $(P,\mathcal{L})$ where $\mathcal{L}$ is a family of subsets on a ground finite set $P$, such that $|l\cap l^\prime|\leq 1$, for every $l,l^\prime \in \mathcal{L}$. The elements of $P$ and $\mathcal{L}$ are called points and ... More
A Geometrical Root Finding Method for Polynomials, with Complexity AnalysisAug 20 2013The usual methods for root finding of polynomials are based on the iteration of a numerical formula for improvement of successive estimations. The unpredictable nature of the iterations prevents to search roots inside a pre-specified region of complex ... More
Numerical approximation of the potential in the two-dimensional inverse scattering problemJul 28 2015Oct 27 2015We present an iterative algorithm to compute numerical approximations of the potential for the Schr\"odinger operator from scattering data. Four different types of scattering data are used as follows: fixed energy, fixed incident angle, backscattering ... More
Constraints on the mass and radius of the accreting neutron star in the Rapid BursterApr 16 2012The Rapid Burster (MXB 1730-335) is a unique object, showing both type I and type II X-ray bursts. A type I burst of the Rapid Burster was observed with Swift/XRT on 2009 March 5, showing photospheric radius expansion for the first time in this source. ... More
Complete synchronization equivalence in asynchronous and delayed coupled mapsDec 11 2015Jun 14 2016Coupled map lattices are paradigmatic models of many collective phenomena. However, quite different patterns can emerge depending on the updating scheme. While in early versions, maps were updated synchronously, there has been in recent years a concern ... More
Wave propagation with irregular dissipation and applications to acoustic problems and shallow watersMay 03 2017In this paper we consider an acoustic problem of wave propagation through a discontinuous medium. The problem is reduced to the dissipative wave equation with distributional dissipation. We show that this problem has a so-called very weak solution, we ... More
Gravitational and electromagnetic signatures of accretion into a charged black holeDec 22 2016We present the derivation and the solutions to the coupled electromagnetic and gravitational perturbations with sources in a charged black hole background. We work in the so called ghost gauge and consider as source of the perturbations the infall of ... More
A splitting theorem for compact Vaisman manifoldsDec 01 2015Mar 21 2016We extend to metric compact mapping tori a splitting result for coK\"ahler manifolds. In particular, we prove that a compact Vaisman manifold is finitely covered by the product of a Sasakian manifold and a circle.
Semilinear integro-differential equations, I: odd solutions with respect to the Simons coneMar 12 2019This is the first of two papers concerning saddle-shaped solutions to the semilinear equation $L_K u = f(u)$ in $\mathbb{R}^{2m}$, where $L_K$ is a linear elliptic integro-differential operator and $f$ is of Allen-Cahn type. Saddle-shaped solutions are ... More
Semantics for Possibilistic Disjunctive ProgramsJun 03 2011In this paper, a possibilistic disjunctive logic programming approach for modeling uncertain, incomplete and inconsistent information is defined. This approach introduces the use of possibilistic disjunctive clauses which are able to capture incomplete ... More