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Plane branches with Newton nondegenerate polarsJan 27 2016We characterize the equisingularity classes of irreducible plane curve germs whose general members have a Newton nondegenerate general polar curve. In addition, we give explicit Zariski open sets of curves in such equisingularity classes whose general ... More

Disjointly homogeneous Banach lattices and applicationsSep 04 2015This is a survey on disjointly homogeneous Banach lattices and their applicactions. Several structural properties of this class are analyzed. In addition we show how these spaces provide a natural framework for studying the compactness of powers of operators ... More

Buryak-Okounkov formula for the n-point function and a new proof of the Witten conjectureFeb 08 2019Mar 14 2019We identify the formulas of Buryak and Okounkov for the n-point functions of the intersection numbers of psi-classes on the moduli spaces of curves. This allows us to combine the earlier known results and this one into a principally new proof of the famous ... More

Buryak-Okounkov formula for the n-point function and a new proof of the Witten conjectureFeb 08 2019We identify the formulas of Buryak and Okounkov for the n-point functions of the intersection numbers of psi-classes on the moduli spaces of curves. This allows us to combine the earlier known results and this one into a principally new proof of the famous ... More

Global product structure for a space of special matricesAug 23 2018The importance of the Hurwitz Metzler matrices and the Hurwitz symmetric matrices can be appreciated in different applications: communication networks, biology and economics are some of them. In this paper, we use an approach of differential topology ... More

Rewriting and narrowing for constructor systems with call-time choice semanticsSep 12 2012Oct 10 2012Non-confluent and non-terminating constructor-based term rewrite systems are useful for the purpose of specification and programming. In particular, existing functional logic languages use such kind of rewrite systems to define possibly non-strict non-deterministic ... More

Infinite series in cohomology: attractors and Conley indexFeb 07 2018In this paper we study the cohomological Conley index of arbitrary isolated invariant continua for continuous maps $f \colon U \subseteq \mathbb{R}^d \to \mathbb{R}^d$ by analyzing the topological structure of their unstable manifold. We provide a simple ... More

Scaling of graphene field-effect transistors supported on hexagonal boron nitride: radio-frequency stability as a limiting factorApr 28 2017Oct 04 2017The quality of graphene in nanodevices has increased hugely thanks to the use of hexagonal boron nitride as a supporting layer. This paper studies to which extent hBN together with channel length scaling can be exploited in graphene field effect transistors ... More

A simple proof of a theorem of sensitivityOct 30 2017Nov 20 2017We prove that every transitive and non minimal semigroup with dense minimal points is sensitive

$C^1$ stability of endomorphisms on two dimensional manifoldsDec 21 2017A set of necessary conditions for $C^1$ stability of noninvertible maps is presented. It is proved that the conditions are sufficient for $C^1$ stability in compact oriented manifolds of dimension two. An example given by F.Przytycki in 1977 is shown ... More

An example of a map which is $C^2$ robustly transitive but not $C^1$ (robustly transitive)Jun 22 2016The aim of this work is to exhibit an example of an endomorphism of $\T^{2}$ which is $C^2$-robustly transitive but not $C^1$-robustly transitive.

Classification of empty lattice $4$-simplices of width larger than twoApr 24 2017Feb 14 2018A lattice $d$-simplex is the convex hull of $d+1$ affinely independent integer points in ${\mathbb R}^d$. It is called empty if it contains no lattice point apart of its $d+1$ vertices. The classification of empty $3$-simplices is known since 1964 (White), ... More

Deriving sorting algorithms via abductive logic program transformationOct 04 2018Logic program transformation by the unfold/fold method ad- vocates the writing of correct logic programs via the application of some rules to a naive program. This work focuses on how to overcome subgoal- introduction difficulties in synthesizing efficient ... More

Pile-up corrections in laser-driven pulsed x-ray sourcesNov 22 2016May 31 2018A formalism for treating the pile-up produced in solid-state detectors by laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector, assuming ... More

Epireflections in topological algebraic structuresApr 04 2017Nov 20 2018Let $\sR$ be an epireflective category of $\topo$ and let $F_\sR$\, be the epireflective functor associated with $\sR$. If $\sA$ denotes a (semi)topological algebraic subcategory of $\topo$, we study when $F_\sR\,(A)$ is an epireflective subcategory of ... More

Pile-up corrections in laser-driven pulsed x-ray sourcesNov 22 2016A formalism for treating the pile-up produced in laser-driven pulsed x-ray sources has been developed. It allows the direct use of x-ray spectroscopy without artificially decreasing the number of counts in the detector. The influence of the pile-up on ... More

Diagnostic of electron temperature from bremsstrahlung in overdense targetsJan 19 2018Models for characterization of laser-accelerated electron via its produced bremsstrahlung are provided for both thin and thick targets. An effective temperature functional is proposed to overcome the so-called cold and hot "temperatures" in the emission ... More

Smooth Lie group actions are parametrized diffeological subgroupsDec 01 2010We show that every effective smooth action of a Lie group G on a manifold M is a diffeomorphism from G onto its image in Diff(M), where the image is equipped with the subset diffeology of the functional diffeology.

Jacobi groupoids and generalized Lie bialgebroidsAug 05 2002Jacobi groupoids are introduced as a generalization of Poisson and contact groupoids and it is proved that generalized Lie bialgebroids are the infinitesimal invariants of Jacobi groupoids. Several examples are discussed.

Spectral methods for bivariate Markov processes with diffusion and discrete components and a variant of the Wright-Fisher modelJul 19 2011The aim of this paper is to study differential and spectral properties of the infinitesimal operator of two dimensional Markov processes with diffusion and discrete components. The infinitesimal operator is now a second-order differential operator with ... More

On the Gauss curvature of compact surfaces in homogeneous 3-manifoldsMar 10 2009Compact flat surfaces of homogeneous Riemannian 3-manifolds with isometry group of dimension 4 are classified. Non-existence results for compact constant Gauss curvature surfaces in these 3-manifolds are established.

Pbca-type In2O3: the lost pressure-induced post-corundum phaseNov 26 2013Contradictory results of high-pressure studies in cubic bixbyite-type indium oxide (c-In2O3) at room temperature (RT) have motivated us to perform high-pressure powder x-ray diffraction and Raman scattering measurements in this material. On increasing ... More

Smear correction of highly-variable, frame-transfer-CCD images with application to polarimetryJun 11 2015Image smear, produced by the shutter-less operation of frame transfer CCD detectors, can be detrimental for many imaging applications. Existing algorithms used to numerically remove smear, do not contemplate cases where intensity levels change considerably ... More

Automorphism groups of simplicial complexes of infinite type surfacesFeb 13 2014Let S be any orientable surface of infinite genus with a finite number of boundary components. In this work we consider the curve complex C(S), the nonseparating curve complex N(S) and the Schmutz graph G(S) of S. When all the topological ends of S carry ... More

On the probabilistic approach to the solution of generalized fractional differential equations of Caputo and Riemann-Liouville typeSep 14 2015Dec 03 2015This paper provides a probabilistic approach to solve linear equations involving Caputo and Riemann-Liouville type derivatives. Using the probabilistic interpretation of these operators as the generators of interrupted Feller processes, we obtain well-posedness ... More

Multi-Atlas Segmentation of Biomedical Images: A SurveyDec 10 2014Jun 12 2015Multi-atlas segmentation (MAS), first introduced and popularized by the pioneering work of Rohlfing, Brandt, Menzel and Maurer Jr (2004), Klein, Mensh, Ghosh, Tourville and Hirsch (2005), and Heckemann, Hajnal, Aljabar, Rueckert and Hammers (2006), is ... More

About $C^{1}$-minimality of the hyperbolic Cantor setsJun 17 2013Jan 27 2014In this work we prove that a $C^{1+\alpha}$-hyperbolic Cantor set contained in $S^1$, close to an affine Cantor set, is not $C^{1}$-minimal.

A dimensao espacial das fases da Lua: contribuicoes para uma proposta de ensinoMay 12 2015In this chapter, we present some reflections about the learning process -and its implications in the teaching- of notions related to the phases of the Moon.

Bayesian inversion in resin transfer moldingJul 12 2017Sep 17 2017We study the Bayesian inverse problem of inferring the permeability of a porous medium within the context of a moving boundary framework motivated by Resin Transfer Molding (RTM), one of the most commonly used processes for manufacturing fiber-reinforced ... More

Tailoring dual reversal modes by helicity control in ferromagnetic nanotubesApr 10 2019We investigate the effects of the competition between exchange ($J$) and dipolar ($D$) interactions on the magnetization reversal mechanisms of ferromagnetic nanotubes. Using first atomistic Monte Carlo (MC) simulations for a model with Heisenberg spins ... More

The conjugation method in symplectic dynamicsMay 30 2016We prove the existence of minimal symplectomorphisms and strictly ergodic contactomorphisms on manifolds which admit a locally free $\mathbb{S}^1$--action by symplectomorphisms and contactomorphisms, respectively. The proof adapts the conjugation method, ... More

Embedding a pair of graphs in a surface, and the width of 4-dimensional prismatoidsFeb 13 2011Apr 15 2011A prismatoid is a polytope with all its vertices contained in two parallel facets, called its bases. Its width is the number of steps needed to go from one base to the other in the dual graph. The author recently showed in arXiv:1006.2814 that the existence ... More

Submanifolds of symplectic manifolds with contact borderJul 06 2000We construct symplectic submanifolds of symplectic manifolds with contact border. The boundary of such submanifolds is shown to be a contact submanifold of the contact border. We also give a topological characterization of the constructed submanifolds ... More

Lefschetz type pencils on contact manifoldsJul 06 2000We define the concept of Lefschetz contact pencil and we show the existence of such structures on any contact manifold. The main idea of the proof is a generalization of the Donaldson arguments used in the symplectic case. We will analyze some of the ... More

The Cayley trick and triangulations of products of simplicesDec 02 2003Apr 08 2004We use the Cayley Trick to study polyhedral subdivisions of the product of two simplices. For arbitrary (fixed) $l$, we show that the numbers of regular and non-regular triangulations of $\Delta^l\times\Delta^k$ grow, respectively, as $k^{\Theta(k)}$ ... More

Non-connected toric Hilbert schemesApr 03 2002Nov 13 2003We construct small (50 and 26 points, respectively) point sets in dimension 5 whose graphs of triangulations are not connected. These examples improve our construction in J. Amer. Math. Soc., 13:3 (2000), 611--637 not only in size, but also in that their ... More

The Cauchy problem for indefinite improper affine spheres and their Hessian equationFeb 22 2013Apr 11 2013We give a conformal representation for indefinite improper affine spheres which solve the Cauchy problem for their Hessian equation. As consequences, we can characterize their geodesics and obtain a generalized symmetry principle. Then, we classify the ... More

Finite size scaling analysis of a nonequilibrium phase transition in the naming game modelSep 09 2016We realize an extensive numerical study of the Naming Game model with a noise term which accounts for perturbations. This model displays a non-equilibrium phase transition between an absorbing ordered consensus state, which occurs for small noise, and ... More

On the locus formed by the maximum heights of projectile motion with air resistanceJan 04 2010Mar 20 2010We present an analysis on the geometrical place formed by the set of maxima of the trajectories of a projectile launched in a media with linear drag. Such a place, the locus of apexes, is written in term of the Lambert $W$ function in polar coordinates, ... More

Anomalous diffusion in the resonant quantum kicked rotorAug 31 2009Mar 26 2010We study the resonances of the quantum kicked rotor subjected to an excitation that follows a deterministic time-dependent prescription. For the primary resonances we find an analytical relation between the long-time behavior of the standard deviation ... More

Remote Filters and Discretely Generated SpacesDec 05 2013Dec 10 2015Alas, Junqueira and Wilson asked whether there is a discretely generated locally compact space whose one point compactification is not discretely generated and gave a consistent example using CH. Their construction uses a remote filter in $\omega\times{}^{\omega}2$ ... More

Fibers of pencils of curves on smooth surfacesMay 12 2006Jul 01 2008Let $X$ be a smooth projective surface such that linear and numerical equivalence of divisors on $X$ coincide and let $\sigma\subseteq |D|$ be a linear pencil on $X$ with integral general fibers. A fiber of $\sigma$ will be called special if either it ... More

The return branch of viscous fingersMay 18 2005We report a simple experiment of two-dimensional pattern formation in a circular Hele-Shaw cell, showing the appearance of a return branch that is equivalent to the upward-connecting leader of lightning. Injecting water from the center into a foam filled ... More

Complex patterns and tip effect evolutionMay 10 2005We studied the formation of complex patterns using a variational principle and a standard energy functional. These patterns evolve by letting the system to search for the optimal configuration of a high conductivity channel, that in one dimension is equivalent ... More

Understanding the complex patterns of snow crystalsJun 25 2002We will show that the complex shapes of snow crystals can be explained from a simple basic mechanism that is also responsible for the appearance of many others structures in nature. We expect that this new physical mechanism, that follows from minimizing ... More

On Type 0 Open String Amplitudes and the Tensionless LimitNov 18 2013Jun 30 2014The sum over planar multi-loop diagrams in the NS+ sector of type 0 open strings in flat spacetime has been proposed by Thorn as a candidate to resolve non-perturbative issues of gauge theories in the large $N$ limit. With $SU (N)$ Chan-Paton factors, ... More

Liftings of Nichols algebras of diagonal type III. Cartan type $G_2$Jul 26 2016Jan 19 2017We complete the classification of Hopf algebras whose infinitesimal braiding is a principal Yetter-Drinfeld realization of a braided vector space of Cartan type $G_2$ over a cosemisimple Hopf algebra. We develop a general formula for a class of liftings ... More

Shape optimisation with nearly conformal transformationsOct 17 2017Oct 19 2017In shape optimisation it is desirable to obtain deformations of a given mesh without negative impact on the mesh quality. We propose a new algorithm using least square formulations of the Cauchy-Riemann equations. Our method allows to deform meshes in ... More

Multisymplectic geometry and Lie groupoidsDec 22 2013We study higher-degree generalizations of symplectic groupoids, referred to as {\em multisymplectic groupoids}. Recalling that Poisson structures may be viewed as infinitesimal counterparts of symplectic groupoids, we describe "higher'' versions of Poisson ... More

Spectra of symmetric powers of graphs and the Weisfeiler-Lehman refinementsJan 15 2008The k-th power of a n-vertex graph X is the iterated cartesian product of X with itself. The k-th symmetric power of X is the quotient graph of certain subgraph of its k-th power by the natural action of the symmetric group. It is natural to ask if the ... More

Countable dense homogeneity of function spacesApr 09 2019In this paper we consider the question of when the space $C_p(X)$ of continuous real-valued functions on $X$ with the pointwise convergence topology is countable dense homogeneous. In particular, we focus on the case when $X$ is countable with a unique ... More

F-purity versus log canonicity for polynomialsDec 12 2011In this article, we consider the conjectured relationship between F-purity and log canonicity for polynomials over the complex numbers. We associate to a collection M of n monomials a rational polytope P contained in [0,1]^n. Using P and the Newton polyhedron ... More

Paraphrasing verbal metonymy through computational methodsSep 18 2017Verbal metonymy has received relatively scarce attention in the field of computational linguistics despite the fact that a model to accurately paraphrase metonymy has applications both in academia and the technology sector. The method described in this ... More

Delta-epsilon functions and uniform continuity on metric spacesOct 09 2017Under certain general conditions, an explicit formula to compute the greatest delta-epsilon function of a continuous function is given. From this formula, a new way to analyze the uniform continuity of a continuous function is given. Several examples ... More

A Whitney map onto the Long ArcDec 05 2013Feb 12 2014In a recent paper, Garc\'{\i}a-Velazquez has extended the notion of Whitney map to include maps with non-metrizable codomain and left open the question of whether there is a continuum that admits such a Whitney map. In this paper, we consider two examples ... More

Compact minimal surfaces in the Berger spheresJul 07 2010We construct compact arbitrary Euler characteristic orientable and non-orientable minimal surfaces in the Berger spheres. Besides we show an interesting family of surfaces that are minimal in every Berger sphere, characterizing them by this property. ... More

Computing the Convolution of Analog and Discrete Time Exponential Signals AlgebraicallyJun 26 2016We present a procedure for computing the convolution of exponential signals without the need of solving integrals or summations. The procedure requires the resolution of a system of linear equations involving Vandermonde matrices. We apply the method ... More

Recent progress on the combinatorial diameter of polytopes and simplicial complexesJul 22 2013The Hirsch conjecture, posed in 1957, stated that the graph of a $d$-dimensional polytope or polyhedron with $n$ facets cannot have diameter greater than $n - d$. The conjecture itself has been disproved, but what we know about the underlying question ... More

Self-similar Radiation from Numerical Rosenau-Hyman CompactonsAug 03 2007The numerical simulation of compactons, solitary waves with compact support, is characterized by the presence of spurious phenomena, as numerically-induced radiation, which is illustrated here using four numerical methods applied to the Rosenau-Hyman ... More

Bayesian optimization for tuning and selecting hybrid-density functionalsMar 26 2019Hybrid-density functional methods such as B3LYP are widely used across different fields to predict physical properties of molecular and material systems. The optimization of hybrid-density functionals is computationally demanding. The machine learning ... More

ScratchR: Sharing User-generated Programmable MediaJul 05 2015In this paper, I describe a platform for sharing programmable media on the web called ScratchR. As the backbone of an on-line community of creative learners, ScratchR will give members access to an audience and inspirational ideas from each other. ScratchR ... More

On the zeros of the Pearcey integral and a Rayleigh-type equationJun 02 2015In this work we find a sequence of functions at which the Pearcey function is identically zero. The sequence of functions can be expressed in terms of a second order non-linear ODE, which happens to be the Rayleigh-type. As a byproduct of these facts, ... More

The Duality between Ideals of Multilinear Operators and Tensor NormsDec 01 2018We develop the duality theory between ideals of multilinear operators and tensor norms that arises from the geometric approach of $\Sigma$-operators. To this end, we introduce and develop the notions of $\Sigma$-ideals of multilinear operators and $\Sigma$-tensor ... More

A note on convergence of solutions of total variation regularized linear inverse problemsNov 17 2017Mar 26 2018In a recent paper by A. Chambolle et al. [Geometric properties of solutions to the total variation denoising problem. Inverse Problems 33, 2017] it was proven that if the subgradient of the total variation at the noise free data is not empty, the level-sets ... More

A framework for fake review detection in online consumer electronics retailersMar 29 2019The impact of online reviews on businesses has grown significantly during last years, being crucial to determine business success in a wide array of sectors, ranging from restaurants, hotels to e-commerce. Unfortunately, some users use unethical means ... More

Disentangling the role of environmental processes in galaxy clustersMar 14 2012In this work we present the results of a novel approach devoted to disentangle the role of the environmental processes affecting galaxies in clusters. This is based on the analysis of the NUV-r' distributions of a large sample of star-forming galaxies ... More

A search for naphthalene in diffuse interstellar cloudsSep 16 2011We have obtained high resolution optical spectroscopy of 10 reddened O-type stars with UVES at VLT to search for interstellar bands of the naphthalene cation (C$_{10}$H$_{8}$$^+$) in the intervening clouds. No absorption features were detected near the ... More

The Clustering of Galaxies in the Completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmic Flows and Cosmic Web from Luminous Red GalaxiesMay 31 2016Jan 17 2017We present a Bayesian phase-space reconstruction of the cosmic large-scale matter density and velocity fields from the SDSS-III Baryon Oscillations Spectroscopic Survey Data Release 12 (BOSS DR12) CMASS galaxy clustering catalogue. We rely on a given ... More

Rare Speed-up in Automatic Theorem Proving Reveals Tradeoff Between Computational Time and Information ValueJun 14 2015We show that strategies implemented in automatic theorem proving involve an interesting tradeoff between execution speed, proving speedup/computational time and usefulness of information. We advance formal definitions for these concepts by way of a notion ... More

Undecidability and Irreducibility Conditions for Open-Ended Evolution and EmergenceJun 06 2016Dec 27 2016Is undecidability a requirement for open-ended evolution (OEE)? Using methods derived from algorithmic complexity theory, we propose robust computational definitions of open-ended evolution and the adaptability of computable dynamical systems. Within ... More

The Limits of Decidable States on Open-Ended Evolution and EmergenceJun 06 2016Jun 07 2016Is undecidability a requirement for open-ended evolution (OEE)? Using algorithmic complexity theory methods, we propose robust computational definitions for open-ended evolution and adaptability of computable dynamical systems. Within this framework, ... More

Coding-theorem Like Behaviour and Emergence of the Universal Distribution from Resource-bounded Algorithmic ProbabilityNov 06 2017Apr 13 2018Previously referred to as `miraculous' in the scientific literature because of its powerful properties and its wide application as optimal solution to the problem of induction/inference, (approximations to) Algorithmic Probability (AP) and the associated ... More

Bohr-Fourier series on solenoids via its transversal variationMar 01 2019The Bohr-Fourier series development on one dimensional solenoids is analyzed by using invariant functions and extending Bohr's theory through the study of transversal variation

Wealth Distribution Models with Regulations: Dynamics and EquilibriaApr 11 2019Simple agent based exchange models are a commonplace in the study of wealth distribution in an artificial economy. Generally, in a system that is composed of many agents characterized by their wealth and risk-aversion factor, two agents are selected sequentially ... More

The Limits of Decidable States on Open-Ended Evolution and EmergenceJun 06 2016Nov 19 2016Is undecidability a requirement for open-ended evolution (OEE)? Using algorithmic complexity theory methods, we propose robust computational definitions for open-ended evolution and adaptability of computable dynamical systems. Within this framework, ... More

The differential build-up factorSep 26 2018The build-factor is a magnitude which allows to correct the photon exponential attenuation model to obtain the real value of a certain dosimetric magnitude, like air exposure. Its main weaknesses are the dependences on the response function of such a ... More

SMA millimeter observations of Hot Molecular CoresFeb 11 2014We present Submillimeter Array observations, in the 1.3 mm continuum and the CH_3CN(12-11) line of 17 hot molecular cores associated with young high-mass stars. The angular resolution of the observations ranges from 1".0 to 4".0. The continuum observations ... More

Evidence for the naphthalene cation in a region of the interstellar medium with anomalous microwave emissionSep 04 2008We report high resolution spectroscopy of the moderately reddened (A$_V$=3) early type star Cernis 52 located in a region of the Perseus molecular cloud complex with anomalous microwave emission. In addition to the presence of the most common diffuse ... More

A non-discrete space $X$ with $C_p(X)$ Menger at infinitySep 14 2018In a paper by Bella, Tokg\"os and Zdomskyy it is asked whether there exists a Tychonoff space $X$ such that the remainder of $C_p(X)$ in some compactification is Menger but not $\sigma$-compact. In this paper we prove that it is consistent that such space ... More

Reversible filtersJan 15 2016Mar 03 2016A space is reversible if every continuous bijection of the space onto itself is a homeomorphism. In this paper we study the question of which countable spaces with a unique non-isolated point are reversible. By Stone duality, these spaces correspond to ... More

Non-meager $P$-filters are Countable Dense HomogeneousSep 18 2018We prove that if $\mathcal{F}$ is a non-meager $P$-filter, then both $\mathcal{F}$ and ${}^\omega\mathcal{F}$ are countable dense homogeneous spaces.

Some remarks on the Robust Stackelberg controllability for the heat equation with controls on the boundaryFeb 08 2019In this paper, we present some controllability results for the heat equation in the framework of hierarchic control. We present a Stackelberg strategy combining the concept of controllability with robustness: the main control (the leader) is in charge ... More

Tuning oxygen vacancy diffusion through strain in SrTiO$_3$ thin filmsJul 03 2018Understanding the diffusion of oxygen vacancies in oxides under different external stimuli is crucial for the design of ion-based electronic devices, improve catalytic performance, etc. In this manuscript, using an external electric field produced by ... More

Bautin bifurcation in a minimal model of immunoeditingJul 03 2018One of the simplest model of immune surveillance and neoplasia was proposed by Delisi and Resigno. Later Liu et al proved the existence of non-degenerate Takens-Bogdanov bifurcations defining a surface in the whole set of five positive parameters. In ... More

On the structure of abelian profinite groupsNov 20 2018A subgroup $G$ of a product $\prod\limits_{i\in\mathbb{N}}G_i$ is \emph{rectangular} if there are subgroups $H_i$ of $G_i$ such that $G=\prod\limits_{i\in\mathbb{N}}H_i$. We say that $G$ is \emph{weakly rectangular} if there are finite subsets $F_i\subseteq ... More

Do deep nets really need weight decay and dropout?Feb 20 2018Jul 12 2018The impressive success of modern deep neural networks on computer vision tasks has been achieved through models of very large capacity compared to the number of available training examples. This overparameterization is often said to be controlled with ... More

Balls and Funnels: Energy Efficient Group-to-Group AnycastsMay 23 2016We introduce group-to-group anycast (g2g-anycast), a network design problem of substantial practical importance and considerable generality. Given a collection of groups and requirements for directed connectivity from source groups to destination groups, ... More

Plane Gossip: Approximating rumor spread in planar graphsDec 05 2016Jul 14 2017We study the design of schedules for multi-commodity multicast; we are given an undirected graph $G$ and a collection of source destination pairs, and the goal is to schedule a minimum-length sequence of matchings that connects every source with its respective ... More

Morse families in optimal control problemsNov 19 2012We geometrically describe optimal control problems in terms of Morse families in the Hamiltonian framework. These geometric structures allow us to recover the classical first order necessary conditions for optimality and the starting point to run an integrability ... More

Hot carrier and hot phonon coupling during ultrafast relaxation of photoexcited electrons in grapheneFeb 01 2016We study, by means of a Monte Carlo simulator, the hot phonon effect on the relaxation dynamics in photoexcited graphene and its quantitative impact as compared to considering an equilibrium phonon distribution. Our multi-particle approach indicates that ... More

Random loose packing and an order parameter for the parking lot modelMay 25 2010We have obtained the random loose packing fraction of the parking lot model (PLM) by taking the limit of infinite compactivity in the two-variable statistical description of Tarjus and Viot for the PLM. The PLM is a stochastic model of adsorption and ... More

Variational approach to vortex penetration and vortex interactionJun 06 2008A variational calculation for vortex penetration is presented. Variational trial functions for the Meissner state are combined with variational functions for a vortex near the surface. The latter is based on Clem's trial solutions for a vortex in bulk, ... More

Data augmentation instead of explicit regularizationJun 11 2018Dec 09 2018Modern deep artificial neural networks have achieved impressive results through models with a very large number of parameters---compared to the number of training examples---that control overfitting with the help of regularization. Regularization can ... More

Pre-Schwarzian and Schwarzian derivatives of harmonic mappingsOct 08 2012In this paper we introduce a definition of the pre-Schwarzian and the Schwarzian derivatives of any locally univalent harmonic mapping $f$ in the complex plane without assuming any additional condition on the (second complex) dilatation $\omega_f$ of ... More

Minimal digraph obstructions for small matricesMay 31 2016Given a $\{ 0, 1, \ast \}$-matrix $M$, a minimal $M$-obstruction is a digraph $D$ such that $D$ is not $M$-partitionable, but every proper induced subdigraph of $D$ is. In this note we present a list of all the $M$-obstructions for every $2 \times 2$ ... More

Generalized Fick Jacobs Approach for describing Adsorption Desorption Kinetics in Irregular Pores under Non Equilibrium ConditionsApr 28 2016We present a study exploring the range of applicability of a generalized Fick Jacobs equation in the case when diffusive mass transport of a fluid along a pore includes chemical reactions in the bulk and pore surface. The study contemplates nonequilibrium ... More

Towards a Hamilton-Jacobi Theory for Nonholonomic Mechanical SystemsMay 25 2007Nov 07 2007In this paper we obtain a Hamilton-Jacobi theory for nonholonomic mechanical systems. The results are applied to a large class of nonholonomic mechanical systems, the so-called \v{C}aplygin systems.

Energy Exchange Calculations in a Simple Mechanical System to Investigate the Origin of FrictionJul 19 2017Oct 30 2018The microscopic origin of friction is an important topic in science and technology. To date, noteworthy aspects of it remain unsolved. In an effort to shed some light on the possible mechanisms that could give rise to the macroscopic emergence of friction, ... More

Evaluation of Gaussian approximations for data assimilation in reservoir modelsDec 08 2012In this paper we propose to numerically assess the performance of standard Gaussian approximations to probe the posterior distribution that arises from Bayesian data assimilation in petroleum reservoirs. In particular we assess the performance of (i) ... More

Stochastic LU factorizations, Darboux transformations and urn modelsJun 08 2017We consider UL (and LU) decompositions of the one-step transition probability matrix of a random walk with state space the nonnegative integers, with the condition that both upper and lower triangular matrices in the factorization are also stochastic ... More