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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

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

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

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

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

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

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

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 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

Tight neighborhoods of contact submanifoldsFeb 20 2018We prove that any small enough neighborhood of a closed contact submanifold is always tight under a mild assumption on its normal bundle. The non-existence of $C^0$--small positive loops of contactomorphisms in general overtwisted manifolds is shown as ... More

Design of two combined health recommender systems for tailoring messages in a smoking cessation appAug 25 2016Oct 14 2016In this article, we describe the design of two recommender systems (RS) designed to support the smoking cessation process through a mobile application. We plan to use a hybrid RS (content-based, utility-based, and demographic filtering) to tailor health ... More

Dynamics and eigenvalues in dimension zeroJul 20 2018Nov 21 2018Let $X$ be a compact, metric and totally disconnected space and let $f:X\to X$ be a continuos map. We relate the eigenvalues of $f_{*}:\check{H}_{0}(X;\mathbb{C})\to\check{H}_{0}(X;\mathbb{C})$ to dynamical properties of $f$, roughly showing that if the ... 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

About the homological discrete Conley index of isolated invariant acyclic continuaFeb 05 2013This article includes an almost self-contained exposition on the discrete Conley index and its duality. We work with a local homeomorphism of $\mathds{R}^d$ and an invariant and isolated acyclic continuum, such as a cellular set or a fixed point. In this ... More

A proof of the Trisecant Identity through the Fourier-Mukai transformNov 09 2010Using the technique of the Fourier-Mukai transform we give an explicit set of generators of the ideal defining an algebraic curve as a subscheme of its Jacobian. Essentially, these ideals are generated by the Fay's trisecant identities.

Study of the 5p3/2 -> 6p3/2 electric dipole forbidden transition in atomic rubidium using optical-optical double resonance spectroscopyJun 19 2015Direct evidence of excitation of the 5p3/2 -> 6p3/2 electric dipole forbidden transition in atomic rubidium is presented. The experiments were performed in a room temperature rubidium cell with continuous wave extended cavity diode lasers. Optical-optical ... More

Induced nuclear activity in galaxy pairs with different morphologies (E+E), (E+S) and (S+S)Sep 07 2015We analysed 385 galactic spectra from the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) that belong to the catalog of isolated pairs of galaxies by Karachentsev. The spectra corresponds to physical pairs of galaxies as defined by V $\leq$ 1200 Km/s ... 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

Alternating maps on Hatcher-Thurston graphsNov 30 2016Let $S_{1}$ and $S_{2}$ be connected orientable surfaces of genus $g_{1}, g_{2} \geq 3$, $n_{1},n_{2} \geq 0$ punctures, and empty boundary. Let also $\varphi: \mathcal{HT}(S_{1}) \rightarrow \mathcal{HT}(S_{2})$ be an edge-preserving alternating map ... More

Edge-preserving maps of curve graphsNov 25 2016Suppose $S_{1}$ and $S_{2}$ are orientable surfaces of finite topological type such that $S_{1}$ has genus at least $3$ and the complexity of $S_{1}$ is an upper bound of the complexity of $S_{2}$. Let $\varphi : \mathcal{C}(S_{1}) \rightarrow \mathcal{C}(S_{2})$ ... More

Length 3 Edge-Disjoint Paths and Partial OrientationJan 31 2012In 2003, it was claimed that the following problem was solvable in polynomial time: do there exist k edge-disjoint paths of length exactly 3 between vertices s and t in a given graph? The proof was flawed, and we show that this problem is NP-hard even ... More

Robust utility maximization for Lévy processes: Penalization and solvabilityJun 04 2012In this paper the robust utility maximization problem for a market model based on L\'evy processes is analyzed. The interplay between the form of the utility function and the penalization function required to have a well posed problem is studied, and ... More

The regularizing Levenberg-Marquardt scheme for history matching of petroleum reservoirs,Feb 14 2013In this paper we study a history matching approach that consists of finding stable approximations to the problem of minimizing the weighted least-squares functional that penalizes the misfit between the reservoir model predictions $G(u)$ and noisy observations ... 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

Iterative regularization for ensemble data assimilation in reservoir modelsJan 21 2014Jun 24 2014We propose the application of iterative regularization for the development of ensemble methods for solving Bayesian inverse problems. In concrete, we construct (i) a variational iterative regularizing ensemble Levenberg-Marquardt method (IR-enLM) and ... More

Zero-sum stochastic differential games without the Isaacs condition: random rules of priority and intermediate HamiltoniansSep 29 2016For a zero-sum stochastic game which does not satisfy the Isaacs condition, we provide a value function representation for an Isaacs-type equation whose Hamiltonian lies in between the lower and upper Hamiltonians, as a convex combination of the two. ... 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

Liftings of Nichols algebras of diagonal type II. All liftings are cocycle deformationsMay 10 2016Oct 03 2016Let $V$ be a braided vector space of diagonal type with a principal realization in the category of Yetter-Drinfeld modules of a cosemisimple Hopf algebra $H$ and such that the Nichols algebra $\mathfrak{B}(V)$ is finitely presented. We show that every ... More

Generalized Lie bialgebroids and Jacobi structuresAug 15 2000The notion of a generalized Lie bialgebroid (a generalization of the notion of a Lie bialgebroid) is introduced in such a way that a Jacobi manifold has associated a canonical generalized Lie bialgebroid. As a kind of converse, we prove that a Jacobi ... More

Lie algebroid foliations and ${\cal E}^1(M)$-Dirac structuresJun 11 2001We prove some general results about the relation between the 1-cocycles of an arbitrary Lie algebroid $A$ over $M$ and the leaves of the Lie algebroid foliation on $M$ associated with $A$. Using these results, we show that a ${\cal E}^1(M)$-Dirac structure ... 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

Some linear Jacobi structures on vector bundlesJul 24 2000We study Jacobi structures on the dual bundle $A^\ast$ to a vector bundle $A$ such that the Jacobi bracket of linear functions is again linear and the Jacobi bracket of a linear function and the constant function 1 is a basic function. We prove that a ... More

Influence of dimension on the convergence of level-sets in total variation regularizationNov 29 2018We extend some recent results on the Hausdorff convergence of level-sets for total variation regularized linear inverse problems. Dimensions higher than two and measurements in Banach spaces are considered. We investigate the relation between the dimension ... More

Convective regularization for optical flowMay 19 2015Oct 13 2015We argue that the time derivative in a fixed coordinate frame may not be the most appropriate measure of time regularity of an optical flow field. Instead, for a given velocity field $v$ we consider the convective acceleration $v_t + \nabla v v$ which ... More

Minimal surfaces in S^2xS^2Jan 08 2013A general study of minimal surfaces of the Riemannian product of two spheres S^2xS^2 is tackled. We stablish a local correspondence between (non-complex) minimal surfaces of S^2xS^2 and certain pair of minimal surfaces of the sphere S^3. This correspondence ... More

On stable compact minimal submanifoldsDec 03 2010Stable compact minimal submanifolds of the product of a sphere and any Riemannian manifold are classified whenever the dimension of the sphere is at least three. The complete classification of the stable compact minimal submanifolds of the product of ... More

Surfaces with Parallel Mean Curvature Vector in S^2xS^2 and H^2xH^2Jul 11 2008Oct 16 2008Two holomorphic Hopf differentials for surfaces of non-null parallel mean curvature vector in S^2xS^2 and H^2xH^2 are constructed. A 1:1 correspondence between these surfaces and pairs of constant mean curvature surfaces of S^2xR and H^2xR is established. ... More

Primary Spaces, Mackey's Obstruction, and the Generalized Barycentric DecompositionMar 26 2012Nov 07 2013We call a hamiltonian N-space \emph{primary} if its moment map is onto a single coadjoint orbit. The question has long been open whether such spaces always split as (homogeneous) x (trivial), as an analogy with representation theory might suggest. For ... More

Schrödinger Diffusion for Shape Analysis with TextureOct 02 2012In recent years, quantities derived from the heat equation have become popular in shape processing and analysis of triangulated surfaces. Such measures are often robust with respect to different kinds of perturbations, including near-isometries, topological ... More

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

Constraint on the time variation of the fine-structure constant with the SDSS-III/BOSS DR12 quasar sampleJan 03 2015Aug 13 2015From the Sloan Digital Sky Survey (SDSS) Data Release 12, which covers the full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate the possible variation of the fine-structure constant over cosmological time-scales. We analyse ... More

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

Helium ordered trapping in arsenolite under compression: Synthesis of He2As4O6Feb 15 2015The compression of arsenolite (cubic As2O3) has been studied from a joint experimental and theoretical point of view. Experimental X-ray diffraction and Raman scattering measurements of this molecular solid at high pressures with different pressure-transmitting ... More

On the solution of two-sided fractional ordinary differential equations of Caputo typeJan 18 2017This paper provides well-posedness results and stochastic representations for the solutions to equations involving both the right- and the left-sided generalized operators of Caputo type. As a special case, these results show the interplay between two-sided ... More

Isomorphisms between curve graphs of infinite-type surfaces are geometricJun 12 2017Let $\phi:\mathcal{C}(S)\to\mathcal{C}(S')$ be a simplicial isomorphism between the curve graphs of two infinite-type surfaces. In this paper we show that in this situation $S$ and $S'$ are homeomorphic and $\phi$ is induced by a homeomorphism $h:S\to ... More

The maximum diameter of pure simplicial complexes and pseudo-manifoldsMar 20 2016We construct $d$-dimensional pure simplicial complexes and pseudo-manifolds (without boundary) with $n$ vertices whose combinatorial diameter grows as $c_d n^{d-1}$ for a constant $c_d$ depending only on $d$, which is the maximum possible growth. Moreover, ... 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

$\mathfrak{c}$-many types of a $Ψ$-spaceMay 31 2018We show that for any cardinal $\omega<\kappa \leq \mathfrak{c}$ with $cf(\kappa) > \omega$, there are $\mathfrak{c}$ many AD families whose $\Psi$-spaces are pairwise non-homeomorphic and they can be Luzin families or branch families of $2^\omega$.

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

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

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

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

Accessible points rotate as prime ends in backward or forward timeDec 22 2016Aug 31 2018Let $X$ be a closed invariant subset of the half--open annulus $\mathbb{A}$ such that $\mathbb{A} \setminus X$ is homeomorphic to $\mathbb{A}$. We prove that either the rotation number of all forward semi--orbits of accessible points of $X$ are well--defined ... More

Greedy type algorithms for RIP matrices. A study of two selection rulesMay 29 2013Some consequences of the Restricted Isometry Property (RIP) of matrices have been applied to develop a greedy algorithm called "ROMP" (Regularized Orthogonal Matching Pursuit) to recover sparse signals and to approximate non-sparse ones. These consequences ... 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

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

FlavorspinFeb 13 2015Jul 02 2015We propose that the flavor structure of the quark sector of the Standard Model is determined by a vectorial SU(2) flavor symmetry, which we dub Flavorspin, under which quarks transform as triplets. The fundamental Yukawa couplings are real and CP violation ... More

Relaxed Disk PackingMay 13 2015Motivated by biological questions, we study configurations of equal-sized disks in the Euclidean plane that neither pack nor cover. Measuring the quality by the probability that a random point lies in exactly one disk, we show that the regular hexagonal ... More

Shape Aware Matching of Implicit Surfaces based on Thin Shell EnergiesSep 22 2015Feb 21 2017A shape sensitive, variational approach for the matching of surfaces considered as thin elastic shells is investigated. The elasticity functional to be minimized takes into account two different types of nonlinear energies: a membrane energy measuring ... 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

The Toda and Painlevé systems associated with semiclassical matrix-valued orthogonal polynomials of Laguerre typeJan 26 2018Consider the Laguerre polynomials and deform them by the introduction in the measure of an exponential singularity at zero. In "Painlev\'e III and a singular linear statistics in Hermitian random matrix ensembles, I", the authors proved that this deformation ... More

Computing with voting treesNov 02 2012The classical paradox of social choice theory asserts that there is no fair way to deterministically select a winner in an election among more than two candidates; the only definite collective preferences are between individual pairs of candidates. Combinatorially, ... More

Neutrino-induced one-pion production revisited: the $ν_μn\toμ^- nπ^+$ channelDec 07 2016We reanalyze our previous studies of neutrino-induced one-pion production on nucleons for outgoing $\pi N$ invariant masses below 1.4 GeV. Our motivation is to get a better description of the $\nu_\mu n\to\mu^- n\pi^+$ cross section, for which current ... More

Critical region for an Ising model coupled to causal dynamical triangulationsFeb 13 2014Jun 12 2015This paper extends results obtained by [15] for the annealed Ising model coupled to two-dimensional causal dynamical triangulations. We employ the Fortuin-Kasteleyn (FK) representation in order to determine a region in the quadrant of parameters $\beta,\mu>0$ ... 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

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

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

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

Nonstandard quasi-monotonicity: an application to the wave existence in a neutral KPP-Fisher equationJan 28 2019We revisit Wu and Zou non-standard quasi-monotonicity approach for proving existence of monotone wavefronts in monostable reaction-diffusion equations with delays. This allows to solve the problem of existence of monotone wavefronts in a neutral KPP-Fisher ... More

Geometric decompositions of almost contact manifoldsNov 20 2012These notes are intended to be an introduction to the use of approximately holomorphic techniques in almost contact and contact geometry. We develop the setup of the approximately holomorphic geometry. Once done, we sketch the existence of the two main ... More

Resolutions of small sets of fat pointsNov 01 2004Jun 01 2005We investigate the minimal graded free resolutions of ideals of at most n+1 fat points in general position in P^n. Our main theorem is that these ideals are componentwise linear. This result yields a number of corollaries, including the multiplicity conjecture ... More

Lins Neto's examples of foliations and the Mori cone of blow-ups of $P^2$Jan 12 2009Oct 26 2009We use a family of algebraic foliations given by A. Lins Neto to provide new evidences to a conjecture, related to the Harbourne-Hirschowitz's one and implying the Nagata's conjecture, which concerns the structure of the Mori cone of blow-ups of $\mathbb{P}^2$ ... More

A class of non-fillable contact structuresNov 13 2006Nov 28 2006A geometric obstruction, the so called "plastikstufe", for a contact structure to not being fillable has been found by K. Niederkruger. This generalizes somehow the concept of overtwisted structure to dimensions higher than 3. This paper elaborates on ... More

Finite dimensional pointed Hopf algebras over S_4Apr 16 2009Oct 06 2009Let k be an algebraically closed field of characteristic 0. We conclude the classification of finite dimensional pointed Hopf algebras whose group of group-likes is S_4. We also describe all pointed Hopf algebras over S_5 whose infinitesimal braiding ... More

Situational diagnosis for preservice elementary teachers on some basic astronomical phenomenaAug 29 2008The present situation of the teaching-learning relationship in astronomy is rarely investigated in our country. This is so, even when it is widely recognized that astronomy is an integral discipline, at the crossroads of advances in physics, geology, ... More

Investigation carried out with pre-service elementary teachers on some basic astronomical topicsJul 06 2010We perform a situational diagnosis in topics of astronomy of pre-service elementary teachers in order to try and develop didactic tools that better collaborate with their formal education. In this work we present the instrument we designed to put in evidence ... More

Some remarks on a current study involving preservice elementary teachers and some basic astronomical phenomenaJun 01 2010Recent studies have shown that not only primary school students but also their future teachers reach science courses with pre-constructed and consistent models of the world surrounding them. These ideas include many misconceptions which turn out to be ... More

Locally conformal symplectic groupoidsJan 10 2003Locally conformal symplectic (l.c.s.) groupoids are introduced as a generalization of symplectic groupoids. We obtain some examples and we prove that l.c.s. groupoids are examples of Jacobi groupoids in the sense of \cite{IM}. Finally, we describe the ... More

Modeling emergence of norms in multi-agent systems by applying tipping points ideasAug 19 2015Norms are known to be a major factor determining humans behavior. It's also shown that norms can be quite effective tool for building agent-based societies. Various normative architectures have been proposed for designing normative multi-agent systems ... More

A New Method for Estimating the Absolute Magnitude Frequency Distribution of Near Earth Asteroids (NEAs)Jan 21 2019The distribution of solar system absolute magnitudes ($H$) for the near-Earth asteroids (NEAs) observable near opposition -- i.e. Amors, Apollos, and Atens ($A^3$) -- is derived from the set of ALL currently known NEAs. The result is based only on common ... More

Second variation of one-sided complete minimal surfacesJun 13 2011The stability and the index of complete one-sided minimal surfaces of certain three-dimensional Riemannian manifolds with positive scalar curvature are studied.

Some acyclic systems of permutations are not realizable by triangulations of a product of simplicesJan 02 2012Jan 05 2012The acyclic system conjecture of Ardila and Ceballos can be interpreted as saying the following: "Every triangulation of the 3-skeleton of a product of two simplices can be extended to a triangulation of the whole product". We show a counter-example to ... More

A note on the Gauss map of complete nonorientable minimal surfacesDec 22 1998We construct complete nonorientable minimal surfaces whose Gauss map omits two points of the projective plane. This result proves that Fujimoto's theorem is sharp in nonorientable case.

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

Bilinear multipliers on Lorenzt spacesOct 04 2007We give one sufficient and two necessary conditions for boundedness between Lebesgue or Lorentz spaces of several classes of bilinear multiplier operators closely connected with the bilinear Hilbert transform.

Sobre un contraejemplo a la conjetura de HirschJul 19 2010This is an expository paper (in Spanish) describing the origin and history of the Hirsch Conjecture about the maximum diameter of graphs of polytopes, and the ideas that led to the counter-example to it recently announced by the author in arxiv:1006.2814 ... More

A counterexample to the Hirsch conjectureJun 14 2010Nov 08 2011The Hirsch Conjecture (1957) stated that the graph of a $d$-dimensional polytope with $n$ facets cannot have (combinatorial) diameter greater than $n-d$. That is, that any two vertices of the polytope can be connected by a path of at most $n-d$ edges. ... 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

Quasi-Frobenius functors. ApplicationsDec 21 2006Sep 03 2008We investigate functors between abelian categories having a left adjoint and a right adjoint that are \emph{similar} (these functors are called \emph{quasi-Frobenius functors}). We introduce the notion of a \emph{quasi-Frobenius bimodule} and give a characterization ... 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

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

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

Optimising the topological information of the $A_\infty$-persistence groupsJun 19 2017Persistent homology typically studies the evolution of homology groups $H_p(X)$ (with coefficients in a field) along a filtration of topological spaces. $A_\infty$-persistence extends this theory by analysing the evolution of subspaces such as $V := \text{Ker}\, ... More

An implementation of Milstein's method for general bounded diffusionsFeb 27 2018Nov 21 2018Despite its generality and powerful convergence properties, Milstein's method for functionals of spatially bounded stochastic differential equations is widely regarded as difficult to implement. This has likely prevented it from being utilised in applications. ... More

The movement of shadows: a teaching proposal for the secondary schoolOct 30 2009A didactic sequence of activities on some topics of Astronomy, related mainly with the length and orientation of shadows cast by a gnomon, the movement of shadows during daytime in different seasons of the year, and finding the true astronomical North, ... More

Receding horizon decoding of convolutional codesSep 03 2009Decoding of convolutional codes poses a significant challenge for coding theory. Classical methods, based on e.g. Viterbi decoding, suffer from being computationally expensive and are restricted therefore to codes of small complexity. Based on analogies ... More