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Continuous-wave mirrorless lasing at 2.21 μm in sodium vaporsAug 31 2018We demonstrate backward-directed continuous-wave (cw) emission at 2.21 {\mu}m generated on the 4P3/2-4S1/2 population-inverted transition in Na vapors two-photon excited with resonant laser light at 589 and 569 nm. Our study of power and atom-number-density ... More

Remote sensing of geomagnetic fields and atomic collisions in the mesosphereFeb 09 2018Magnetic-field sensing has contributed to the formulation of the plate-tectonics theory, the discovery and mapping of underground structures on Earth, and the study of magnetism in other planets. Filling the gap between space-based and near-Earth observation, ... More

Dipolar Rings of Microscopic Ellipsoids: Magnetic Manipulation and Cell EntrapmentApr 13 2016Aug 27 2016We study the formation and dynamics of dipolar rings composed by microscopic ferromagnetic ellipsoids, which self-assemble in water by switching the direction of the applied field. We show how to manipulate these fragile structures and control their shape ... More

The Proper Motion of the Large Magellanic Cloud: A ReanalysisJan 10 2006We have determined the proper motion (PM) of the Large Magellanic Cloud (LMC) relative to four background quasi-stellar objects, combining data from two previous studies made by our group, and new observations carried out in four epochs not included the ... More

Learning Eligibility in Cancer Clinical Trials using Deep Neural NetworksMar 22 2018Jul 25 2018Interventional cancer clinical trials are generally too restrictive, and some patients are often excluded on the basis of comorbidity, past or concomitant treatments, or the fact that they are over a certain age. The efficacy and safety of new treatments ... More

Isotropical Linear Spaces and Valuated Delta-MatroidsApr 28 2010The spinor variety is cut out by the quadratic Wick relations among the principal Pfaffians of an n x n skew-symmetric matrix. Its points correspond to n-dimensional isotropic subspaces of a 2n-dimensional vector space. In this paper we tropicalize this ... More

Computing Tropical Linear SpacesSep 19 2011May 02 2012We define and study the cyclic Bergman fan of a matroid M, which is a simplicial polyhedral fan supported on the tropical linear space T(M) of M and is amenable to computational purposes. It slightly refines the nested set structure on T(M), and its rays ... More

A decomposition for the Schrodinger equation with applications to bilinear and multilinear estimatesJul 27 2015A new decomposition for frequency-localized solutions to the Schrodinger equation is given which describes the evolution of the wavefunction using a weighted sum of Lipschitz tubes. As an application of this decomposition, we provide a new proof of the ... More

Dissipative charging of a quantum batteryFeb 01 2019We show that a cyclic unitary process can extract work from the thermodynamic equilibrium state of an engineered quantum dissipative process. Systems in the equilibrium states of these processes serve as batteries, storing energy. The dissipative process ... More

Holography of negative energy statesSep 13 2018Jan 07 2019Quantum states with negative energy densities have been long known to exist in quantum field theories. We explore the structure of such states for holographic theories using quantum information theory tools and show how certain negative energy states ... More

Partially Hyperbolic Sets with a Dynamically Minimal Invariant LaminationMar 21 2017We study partially hyperbolic sets of C1-diffeomorphisms. For these sets there are defined the strong stable and strong unstable laminations. A lamination is called dynamically minimal when the orbit of each leaf intersects the set densely. We prove that ... More

Twistor spinors with zero on Lorentzian 5-spaceFeb 27 2006We present in this paper a $C^1$-metric on an open neighbourhood of the origin in $\RR^{5}$. The metric is of Lorentzian signature $(1,4)$ and admits a solution to the twistor equation for spinors with a unique isolated zero at the origin. The metric ... More

The Large-Scale 3-point correlation function of SDSS Luminous Red GalaxiesNov 19 2010We present new measurements of the redshift-space three-point correlation function (3PCF) of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS). Using the largest dataset to date, the Data Release 7 (DR7) LRGs, and an improved binning ... More

Integrable Abelian Vortex-like solitonsDec 06 2016We propose a modified version of the Ginzburg-Landau energy functional admitting static solitons and determine all the Painlev\'e-integrable cases of its Bogomolny equations of a given class of models. Explicit solutions are determined in terms of the ... More

The thermodynamic cost of driving quantum systems by their boundariesSep 14 2015Oct 22 2015The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. ... More

On the constancy regions for mixed test idealsAug 25 2012Dec 04 2012In this note we study the partition of $\mathbb{R}_{\geq0}^{n}$ given by the regions where the mixed test ideals $\tau(\mathfrak{a}_{1}^{t_{1}}... \mathfrak{a}_{n}^{t_{n}})$ are constant. We show that each region can be described as the preimage of a ... More

A Theory of Complexity, Condition and RoundoffMar 25 2014Jun 06 2014We develop a theory of complexity for numerical computations that takes into account the condition of the input data and allows for roundoff in the computations. We follow the lines of the theory developed by Blum, Shub, and Smale for computations over ... More

Imaginary Killing Spinors in Lorenztian GeometryFeb 03 2003We study the geometric structure of Lorentzian spin manifolds, which admit imaginary Killing spinors. The discussion is based on the cone construction and a normal form classification of skew-adjoint operators in signature $(2,n-2)$. Derived geometries ... More

Orthogonal Polynomials and Sharp Estimates for the Schrödinger EquationFeb 21 2017Aug 24 2017In this paper we study sharp estimates for the Schr\"odinger operator via the framework of orthogonal polynomials. We use spherical harmonics and Gegenbauer polynomials to prove a new weighted inequality for the Schr\"odinger equation that is maximized ... More

Improving Sparsity in Kernel Adaptive Filters Using a Unit-Norm DictionaryJul 13 2017Kernel adaptive filters, a class of adaptive nonlinear time-series models, are known by their ability to learn expressive autoregressive patterns from sequential data. However, for trivial monotonic signals, they struggle to perform accurate predictions ... More

Genoogle: an indexed and parallelized search engine for similar DNA sequencesJul 10 2015The search for similar genetic sequences is one of the main bioinformatics tasks. The genetic sequences data banks are growing exponentially and the searching techniques that use linear time are not capable to do the search in the required time anymore. ... More

Minimality of one invariant lamination for partially hyperbolic attractorsApr 22 2014We prove that at least one of the two invariant laminations of a strongly partially hyperbolic attractor with one-dimensional center bundle is minimal. This result extends those in [7] about minimal foliations for robustly transitive diffeomorphisms.

Three-dimensional numerical simulations of fast-to-Alfven conversion in sunspotsAug 28 2012The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-beta region of the model. The new wave modes ... More

Counterexamples to Ruelle's inequality in the noncompact caseOct 16 2015In this paper we show that there exists a large family of smooth dynamical systems defined over noncompact spaces that does not satisfy Ruelle's inequality between entropy and Lyapunov exponents.

Twistorial constructions of spacelike surfaces in Lorentzian 4-manifoldsFeb 17 1999We investigate the twistor space and the Grassmannian fibre bundle of a Lorentzian 4-space with natural almost optical structures and its induced CR-structures. The twistor spaces of the Lorentzian space forms $\R^4_1, \Di{S}^4_1$ and $\Di{H}^4_1$ are ... More

A remark on conformal $\SU(p,q)$-holonomyApr 18 2006If the conformal holonomy group $Hol(\mathcal{T})$ of a simply connected space with conformal structure of signature $(2p-1,2q-1)$ is reduced to $\U(p,q)$ then the conformal holonomy is already contained in the special unitary group $\SU(p,q)$. We present ... More

A Sharpened Strichartz Inequality For Radial FunctionsSep 23 2017Jul 25 2018We prove a sharpened version of the Strichartz inequality for radial solutions of the Schr\"odinger equation in $\mathbb{R}^2\times \mathbb{R}$. We establish an improved upper bound for functions that nearly extremize the inequality, with a negative second ... More

A Central Limit Theorem for OperatorsOct 28 2015Nov 28 2015We prove an analogue of the Central Limit Theorem for operators. For every operator $K$ defined on $\mathbb{C}[x]$ we construct a sequence of operators $K_N$ defined on $\mathbb{C}[x_1,...,x_N]$ and demonstrate that, under certain orthogonality conditions, ... More

Ruelle's inequality and Pesin's entropy formula for the geodesic flow on negatively curved noncompact manifoldsJan 12 2016Jun 15 2016In this paper we study different notions of entropy of measure-preserving dynamical systems defined on noncompact spaces. We see that some classical results for compact spaces remain partially valid in this setting. We define a new kind of entropy for ... More

The Standard Candle Method for Type II-Plateau SupernovaeOct 30 2008In this thesis we study the "standardized candle method" using a sample of 37 nearby (redshift < 0.06) Type II-plateau supernovae with BVRI photometry and optical spectroscopy. An analytic procedure is implemented to fit light, color, and velocity curves. ... More

Universal C*-algebras of endomorphisms of groups and partial actionsJun 08 2017Jul 09 2017We present a different way to study the C*-algebra associated with an injective endomorphism of a group G of infinite cokernel. We follow the work of Boava and Exel to construct a partial crossed product representation of that C*-algebra and show properties ... More

Ruelle's inequality in negative curvatureJan 12 2016Jan 16 2018In this paper we study different notions of entropy for measure-preserving dynamical systems defined on noncompact spaces. We see that some classical results for compact spaces remain partially valid in this setting. We define a new kind of entropy for ... More

About Twistor Spinors with Zero in Lorentzian GeometryJun 15 2004Jul 28 2009We describe the local conformal geometry of a Lorentzian spin manifold $(M,g)$ admitting a twistor spinor $\phi$ with zero. Moreover, we describe the shape of the zero set of $\phi$. If $\phi$ has isolated zeros then the metric $g$ is locally conformally ... More

Magnetic phase diagram of YbCo2Si2 derived from magnetization measurementsNov 12 2011Dec 20 2011We report on high-resolution dc-magnetization (M) measurements on a high-quality single crystal of YbCo2Si2. M was measured down to 0.05K and in fields up to 4T, with the magnetic field oriented along the crystallographic directions [100], [110] and [001] ... More

Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121Aug 26 2008We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their color magnitude diagrams ... More

Functional colloidal micro-sieves assembled and guided above a channel-free magnetic striped filmJan 06 2016Colloidal inclusions in lab-on-a-chip devices can be used to perform analytic operations in a non-invasive fashion. We demonstrate here a novel approach to realize fast and reversible micro-sieving operations by manipulating and transporting colloidal ... More

String Dual of N=1 Super Yang-Mills on the CylinderApr 30 2008We study the stringy description of N=1 supersymmetric SU(N) gauge theory on R^{1,2}xS^1. Our description is based on the known Maldacena-Nunez solution, properly modified to account for the compact dimension. The most interesting of its properties is ... More

On pseudo-Hermitian Einstein spacesFeb 14 2005We describe and construct here pseudo-Hermitian structures $\theta$ without torsion (i.e. with transversal symmetry) whose Webster-Ricci curvature tensor is a constant multiple of the exterior differential $d\theta$. We call these structures pseudo-Hermitian ... More

Interpolation Formulas With Derivatives in De Branges SpacesMar 17 2015The purpose of this paper is to prove an interpolation formula involving derivatives for entire functions of exponential type. We extend the interpolation formula derived by J. Vaaler in [37, Theorem 9] to general $L^p$ de Branges spaces. We extensively ... More

An old, metal-poor globular cluster in Sextans A and the metallicity floor of globular cluster systemsApr 01 2019We report the confirmation of an old, metal-poor globular cluster in the nearby dwarf irregular galaxy Sextans A, the first globular cluster known in this galaxy. The cluster, which we designate as Sextans A-GC1, lies some 4.4 arcminutes ($\sim1.8$ kpc) ... More

Possibilities of Recursive GPU Mapping for Discrete Orthogonal SimplicesOct 24 2016The problem of parallel thread mapping is studied for the case of discrete orthogonal $m$-simplices. The possibility of a $O(1)$ time recursive block-space map $\lambda: \mathbb{Z}^m \mapsto \mathbb{Z}^m$ is analyzed from the point of view of parallel ... More

Large gaps imputation in remote sensed imagery of the environmentJun 22 2010Imputation of missing data in large regions of satellite imagery is necessary when the acquired image has been damaged by shadows due to clouds, or information gaps produced by sensor failure. The general approach for imputation of missing data, that ... More

Proper motions of Local Group dwarf spheroidal galaxies I: First ground-based results for FornaxMay 26 2010In this paper we present in detail the methodology and the first results of a ground-based program to determine the absolute proper motion of the Fornax dwarf spheroidal galaxy. The proper motion was determined using bona-fide Fornax star members measured ... More

H - T phase diagram of YbCo2Si2 with H // [100]Oct 30 2009May 23 2011We report on the first high-resolution dc-magnetisation ($M$) measurements on a single crystal of \ycs. $M$ was measured down to 0.05 K and in fields up to 12 T, with the magnetic field $H$ parallel to the crystallographic direction [100]. Two antiferromagnetic ... More

Magnetization study of the energy scales in YbRh$_{2}$Si$_{2}$ under chemical pressureMar 09 2013We present a systematic study of the magnetization in YbRh$_{2}$Si$_{2}$ under slightly negative (6?% Ir substitution) and positive (7% Co substitution) chemical pressure. We show how the critical field $H_{0}$, associated with the high-field Lifshitz ... More

Potential benefits of a block-space GPU approach for discrete tetrahedral domainsJun 28 2016The study of data-parallel domain re-organization and thread-mapping techniques are relevant topics as they can increase the efficiency of GPU computations when working on spatial discrete domains with non-box-shaped geometry. In this work we study the ... More

Ferromagnetic Quantum Criticality in the Quasi-One-Dimensional Heavy Fermion Metal YbNi4P2Aug 22 2011We present a new Kondo-lattice system, YbNi4P2, which is a clean heavy-fermion metal with a severely reduced ferromagnetic ordering temperature at T_C=0.17K, evidenced by distinct anomalies in susceptibility, specific-heat, and resistivity measurements. ... More

A Search for OB Associations Near Southern Long-Period Cepheids. V. AQ Puppis and V620 PuppisOct 15 2012A photometric UBV survey is presented for 610 stars in a region surrounding the Cepheid AQ Puppis and centered southwest of the variable, based upon photoelectric measures for 14 stars and calibrated iris photometry of photographic plates of the field ... More

Non-equilibrium Lorentz gas on a curved spaceJan 12 2007The periodic Lorentz gas with external field and iso-kinetic thermostat is equivalent, by conformal transformation, to a billiard with expanding phase-space and slightly distorted scatterers, for which the trajectories are straight lines. A further time ... More

Natural braneworld inflation and baryogenesisNov 26 2004May 29 2005In natural inflation models, the inflaton is a pseudo Nambu-Goldstone boson and the flatness of the potential is protected by shift symmetries. In this framework, a successful inflation requires the global symmetry to be spontaneously broken at a scale ... More

Rescaling, thinning or complementing? On goodness-of-fit procedures for point process models and Generalized Linear ModelsNov 18 2010Generalized Linear Models (GLMs) are an increasingly popular framework for modeling neural spike trains. They have been linked to the theory of stochastic point processes and researchers have used this relation to assess goodness-of-fit using methods ... More

Metrisability of Painlevé equationsApr 12 2016We solve the metrisability problem for the six Painlev\'e equations, and more generally for all 2nd order ODEs with Painlev\'e property, and determine for which of these equations their integral curves are geodesics of a (pseudo) Riemannian metric on ... More

Tropical schemes, tropical cycles, and valuated matroidsJan 19 2014We show that the weights on a tropical variety can be recovered from the tropical scheme structure proposed by the Giansiracusas in arXiv:1308.0042, so there is a well-defined Hilbert-Chow morphism from a tropical scheme to the underlying tropical cycle. ... More

Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational wavesNov 11 2016The finding of Gravitational Waves by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron ... More

On the M-theory description of supersymmetric gluodynamicsMar 08 2007Jul 13 2007We study the stringy description of N=1 supersymmetric SU(N) gauge theory on R^{1,2} X S^1. Our description is based on the known Klebanov-Strassler and Maldacena-Nunez solutions, properly modified to account for the compact dimension. The presence of ... More

A Simple Algorithm for Computing the Document ArrayDec 21 2018We present a simple algorithm for computing the document array given the string collection and its suffix array as input. Our algorithm runs in linear time using constant workspace for large collections of short strings.

Asymptotic almost-equivalence of abstract evolution systemsApr 14 2009We study the asymptotic behavior of almost-orbits of abstract evolution systems in Banach spaces with or without a Lipschitz assumption. In particular, we establish convergence, convergence in average and almost-convergence of almost-orbits both for the ... More

Agent-based model for the origins of scaling in human languageMay 16 2017Background/Introduction: The Zipf's law establishes that if the words of a (large) text are ordered by decreasing frequency, the frequency versus the rank decreases as a power law with exponent close to -1. Previous work has stressed that this pattern ... More

A sampling theorem for functions in Besov spaces on spaces of homogeneous typeJun 29 2017In this work we establish a sampling theorem for functions in Besov spaces on spaces of homogeneous type as defined in [HY] in the spirit of their recent counterpart for R d established by Jaming-Malinnikova in [JM]. The main tool is the wavelet decomposition ... More

Dissipation in small systems: A Landau-Zener approachFeb 05 2016We establish a stochastic thermodynamics for a Fermionic level driven by a time-dependent force and interacting with initially thermalized levels playing the role of a reservoir. The driving induces consecutive avoided crossings between system and reservoir ... More

Tropical IdealsSep 13 2016Dec 10 2017We introduce and study a special class of ideals, called tropical ideals, in the semiring of tropical polynomials, with the goal of developing a useful and solid algebraic foundation for tropical geometry. The class of tropical ideals strictly includes ... More

Evaluating arbitration and conflict resolution mechanisms in the Spanish WikipediaDec 10 2014In open collaborative projects like Wikipedia, interactions among users can produce tension and misunderstandings. Complex disputes require more sophisticated mechanisms of conflict resolution. In this paper, we examine the case of the Spanish Wikipedia ... More

An Inverse Problem Approach for Content Popularity EstimationOct 26 2015The Internet increasingly focuses on content, as exemplified by the now popular Information Centric Networking paradigm. This means, in particular, that estimating content popularities becomes essential to manage and distribute content pieces efficiently. ... More

Khintchine types of translated coordinate hyperplanesMay 28 2014Jan 14 2015There has been great interest in developing a theory of "Khintchine types" for manifolds embedded in Euclidean space, and considerable progress has been made for curved manifolds. We treat the case of translates of coordinate hyperplanes, decidedly flat ... More

Sample size estimation for power and accuracy in the experimental comparison of algorithmsAug 09 2018Oct 15 2018Experimental comparisons of performance represent an important aspect of research on optimization algorithms. In this work we present a methodology for defining the required sample sizes for designing experiments with desired statistical properties for ... More

Extremal problems in de Branges spaces: the case of truncated and odd functionsDec 02 2014In this paper we find extremal one-sided approximations of exponential type for a class of truncated and odd functions with a certain exponential subordination. These approximations optimize the $L^1(\mathbb{R}, |E(x)|^{-2}dx)$-error, where $E$ is an ... More

Fields of Parametrization and Optimal Affine Reparametrization of Rational CurvesOct 30 2008In this paper we present three related results on the subject of fields of parametrization. Let C be a rational curve over a field of characteristic zero. Let K be a field finitely generated over Q, such that it is a field of definition of C but not a ... More

Superelliptic Affine Lie AlgebrasAug 26 2018Nov 05 2018We consider Lie algebras of the form $\mathfrak{g}\otimes R$ where $\mathfrak{g}$ is a simple complex (finite-dimensional) Lie algebra and $R$ is a ring of the form $\mathbb{C}[t^{\pm1},u ]$ where $u^m\in \mathbb{C}[t]$. We determine a basis for the kernel ... More

UFRGS Participation on the WMT Biomedical Translation Shared TaskMay 06 2019This paper describes the machine translation systems developed by the Universidade Federal do Rio Grande do Sul (UFRGS) team for the biomedical translation shared task. Our systems are based on statistical machine translation and neural machine translation, ... More

On the Chern-Simons topological term at finite temperatureSep 10 1997Sep 11 1997The parity-violating topological term in the effective action for 2+1 massive fermions is computed at finite temperature in the presence of a constant background field strength tensor. Gauge invariance of the finite-temperature effective action is also ... More

Transport and dynamics on open quantum graphsJul 13 2001We study the classical limit of quantum mechanics on graphs by introducing a Wigner function for graphs. The classical dynamics is compared to the quantum dynamics obtained from the propagator. In particular we consider extended open graphs whose classical ... More

Torsion points on y^2=x^6+1Oct 20 1997Let C be the curve y^2=x^6+1 of genus 2 over a field of characteristic zero. Consider C embedded in its Jacobian J by sending one of the points at infinity on C to the origin of J. In this brief note we show that the points of C whose image on J are torsion ... More

Componentwise condition numbers of random sparse matricesJul 07 2008Jul 08 2008We prove an O(log n) bound for the expected value of the logarithm of the componentwise (and, a fortiori, the mixed) condition number of a random sparse n x n matrix. As a consequence, small bounds on the average loss of accuracy for triangular linear ... More

Partial Crossed Product of a group G vs Crossed Product of S(G)May 23 2008In this work we present a new definition to the Partial Crossed Product by actions of inverse semigroups in a C^*-algebra, without using the covariant representations as Sieben did in [5]. Also we present an isomorphism between the partial crossed products ... More

Exact equilibrium state for pair plasmas around Schwarzschild black holesAug 27 2018A pair plasma, with a pressure profile that allow its hydrostatic equilibrium, can be shown to be an exact equilibrium state for a configuration of its constituents rotating in the equatorial plane of a Schwarzschild black hole. This equilibrium state ... More

Higher cohomology for Anosov actions on certain homogeneous spacesJul 23 2011Aug 24 2012We study the smooth untwisted cohomology with real coefficients for the action on [SL(2, R) \times \cdot \cdot \cdot \times SL(2, R)]/{\Gamma} by the subgroup of diagonal matrices, where {\Gamma} is an irreducible lattice. In the top degree, we show that ... More

Computing Hypercircles by Moving HyperplanesJun 07 2011Let K be a field of characteristic zero, alpha algebraic of degree n over K. Given a proper parametrization psi of a rational curve C, we present a new algorithm to compute the hypercircle associated to the parametrization psi. As a consequence, we can ... More

Testing dynamic stabilisation in complex Langevin simulationsOct 28 2016Complex Langevin methods have been successfully applied in theories that suffer from a sign problem such as QCD with a chemical potential. We present and illustrate a novel method (dynamic stabilisation) that ensures that Complex Langevin simulations ... More

A characterization of bad approximabilityJul 03 2017Jan 22 2018We show that badly approximable vectors are exactly those that cannot, for any inhomogeneous parameter, be inhomogeneously approximated at every monotone divergent rate. This implies in particular that Kurzweil's Theorem cannot be restricted to any points ... More

Dependence of sunspot photospheric waves on the depth of the source of solar $p-$modesFeb 03 2017Photospheric waves in sunspots moving radially outwards at speeds faster than the characteristic wave velocities have been recently detected. It has been suggested that they are the visual pattern of $p-$modes excited around 5 Mm beneath the sunspot. ... More

Graded polynomial identities and central polynomials of matrices over an infinite integral domainMar 17 2014Aug 06 2014Let $K$ be an infinite integral domain and $M_{n}(K)$ be the algebra of all $n\times n$ matrices over $K$. This paper aims for the following goals: Find a basis for the graded identities for elementary grading in $M_{n}(K)$ when the neutral component ... More

Tropical schemes, tropical cycles, and valuated matroidsJan 19 2014Dec 10 2017We show that the weights on a tropical variety can be recovered from the tropical scheme structure proposed by the Giansiracusas in arXiv:1308.0042, so there is a well-defined Hilbert-Chow morphism from a tropical scheme to the underlying tropical cycle. ... More

A remark on the well-posedness of the degenerated Zakharov systemDec 07 2013We extend the local well-posedness theory for the Cauchy problem associated to a degenerated Zakharov system. The new main ingredients are the derivation of Strichartz and maximal function norm estimates for the linear solution of a Schrodinger type equation ... More

On graded polynomial identities of $sl_{2}(F)$ over a finite fieldNov 15 2013Apr 14 2015Let $F$ be a finite field of $char F > 3$ and $sl_{2}(F)$ be the Lie algebra of traceless $2\times 2$ matrices over $F$. This paper aims for the following goals: Find a basis for the $\mathbb{Z}_{2}$-graded identities of $sl_{2}(F)$; Find a basis for ... More

Smoothed analysis of componentwise condition numbers for sparse matricesFeb 25 2013We perform a smoothed analysis of the componentwise condition numbers for determinant computation, matrix inversion, and linear equations solving for sparse n times n matrices. The bounds we obtain for the ex- pectations of the logarithm of these condition ... More

Control and Stabilization of the Benjamin-Ono Equation on a Periodic DomainSep 22 2012It was proved by Linares and Ortega that the linearized Benjamin-Ono equation posed on a periodic domain T with a distributed control supported on an arbitrary subdomain is exactly controllable and exponentially stabilizable. The aim of this paper is ... More

Nonequilibrium mesoscopic Fermi reservoirs distributions and particle current through a coherent quantum systemFeb 01 2013We study particle current and occupation distribution in a recently proposed model for coherent quantum transport. In this model a system connected to mesoscopic Fermi reservoirs (mesoreservoir) is driven out of equilibrium by the action of superreservoirs ... More

Tropical Plane Geometric Constructions: a Transfer Technique in Tropical GeometryNov 29 2005Oct 10 2007The notion of geometric construction is introduced. This notion allows to compare incidence configurations in the algebraic and tropical plane. We provide an algorithm such that, given a tropical instance of a geometric construction, it computes sufficient ... More

Smoothed Analysis of Moore-Penrose InversionFeb 25 2010Apr 30 2010We perform a smoothed analysis of the condition number of rectangular matrices. We prove that, asymptotically, the expected value of this condition number depends only of the elongation of the matrix, and not on the center and variance of the underlying ... More

Photon cooling by dispersive atom-field coupling with atomic postselectionApr 08 2019Apr 16 2019We propose, in a Ramsey interferometer, to cool the cavity field to its ground state, starting from a thermal distribution by a dispersive atom-field coupling followed by an atomic postselection. We also analyze the effect of the cavity and atomic losses. ... More

On real tropical bases and real tropical discriminantsNov 09 2013We explore the concept of real tropical basis of an ideal in the field of real Puiseux series. We show explicit tropical bases of zero-dimensional real radical ideals, linear ideals and hypersurfaces coming from combinatorial patchworking. But we also ... More

A characterization of μ-equicontinuity for topological dynamical systemsSep 02 2013Oct 04 2014Two different notions of {\mu}-equicontinuity that apply to topological dynamical systems and probability measures were studied by Gilman (1987) and Huang-Lu-Ye (2011). One was used to classify measure preserving topological dynamical systems and the ... More

Limit behaviour of $μ-$equicontinuous cellular automataOct 27 2014Sep 15 2015The concept of $\mu-$equicontinuity was introduced by Gilman to classify cellular automata. We show that under some conditions the sequence of Cesaro averages of a measure $\mu,$ converge under the actions of a $\mu -$equicontinuous CA. We address questions ... More

Relativizing an incompressible number and an incompressible function through subrecursive extensions of Turing machinesDec 15 2016We show in this article that uncomputability is also a relative property of subrecursive classes built on a recursive relative incompressible function, which acts as a higher-order "yardstick" of irreducible information for the respective subrecursive ... More

A decentralized route to the origins of scaling in human languageMay 16 2017Apr 02 2019The Zipf's law establishes that if the words of a (large) text are ordered by decreasing frequency, the frequency versus the rank decreases as a power law with exponent close to $-1$. Previous work has stressed that this pattern arises from a conflict ... More

Fluctuations of the Longest Common Subsequence for Sequences of Independent BlocksJan 08 2010Nov 12 2010The problem of the fluctuation of the Longest Common Subsequence (LCS) of two i.i.d. sequences of length $n>0$ has been open for decades. There exist contradicting conjectures on the topic. Chvatal and Sankoff conjectured in 1975 that asymptotically the ... More

Interpolation Formulas With Derivatives In De Branges Spaces IIOct 28 2015We consider the problem of reconstruction of entire functions of exponential type $\tau$ that are elements of certain weighted $L^p(\mu)$-spaces from their values and the values of their derivatives up to a fixed order. In this paper we extend the interpolation ... More

The quantum effects of the spin and the Bohm potential in the oblique propagation of magnetosonic wavesOct 01 2010We study the quantum corrections to the oblique propagation of the magnetosonic waves in a warm quantum magnetoplasma composed by mobile ions and electrons. We use a fluid formalism to include quantum corrections due to the Bohm potential and to magnetization ... More

Coulomb gauge QCD as a tool for the excited spectrumSep 28 2010A distinct feature of Coulomb gauge QCD is that it can be formulated in terms of physical, transverse gluons and quarks alone. The state-counting is then transparent, and the gauge is suited for studies of the excited spectrum. Leaving aside exotic spectroscopy, ... More

Local and global well-posedness for the 2D generalized Zakharov-Kuznetsov equationOct 26 2010This paper addresses well-posedness issues for the initial value problem (IVP) associated with the generalized Zakharov-Kuznetsov equation, namely, \{equation*} \quad \left\{\{array}{lll} {\displaystyle u_t+\partial_x \Delta u+u^ku_x = 0,}\qquad (x,y) ... More