Results for "Artur Costa-Pazo"

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One DSL to Rule Them All: IDE-Assisted Code Generation for Agile Data AnalysisApr 18 2019Data analysis is at the core of scientific studies, a prominent task that researchers and practitioners typically undertake by programming their own set of automated scripts. While there is no shortage of tools and languages available for designing data ... More
Memory and Resource Leak Defects and their Repairs in Java ProjectsSep 28 2018Jun 27 2019Despite huge software engineering efforts and programming language support, resource and memory leaks are still a troublesome issue, even in memory-managed languages such as Java. Understanding the properties of leak-inducing defects, how the leaks manifest, ... More
Deep Anomaly Detection for Generalized Face Anti-SpoofingApr 17 2019Face recognition has achieved unprecedented results, surpassing human capabilities in certain scenarios. However, these automatic solutions are not ready for production because they can be easily fooled by simple identity impersonation attacks. And although ... More
Generalized Presentation Attack Detection: a face anti-spoofing evaluation proposalApr 12 2019Over the past few years, Presentation Attack Detection (PAD) has become a fundamental part of facial recognition systems. Although much effort has been devoted to anti-spoofing research, generalization in real scenarios remains a challenge. In this paper ... More
On generalized topological spacesApr 30 2009Dec 15 2010In this paper a systematic study of the category GTS of generalized topological spaces (in the sense of H. Delfs and M. Knebusch) and their strictly continuous mappings begins. Some completeness and cocompleteness results are achieved. Generalized topological ... More
Reduction of integration domain in Triebel-Lizorkin spacesOct 26 2018Jan 02 2019We investigate the comparability of generalized Triebel-Lizorkin and Sobolev seminorms on uniform and non-uniform sets when the integration domain is truncated according to the distance from the boundary. We provide numerous examples of kernels and domains ... More
Encoding spatial data into quantum observablesSep 06 2016Aug 03 2017The focus of this work is a correspondence between the Hilbert space operators on one hand, and doubly periodic generalized functions on the other. The linear map that implements it, referred to as the Q-transform, enables a direct application of the ... More
Mirror symmetry and quantum cohomology of projective bundlesOct 25 2006In an earlier paper we conjectured a relation between the quantum $\mathcal D$-modules of a smooth variety $X$ and the projectivisation of a direct sum of line bundles over it. In this paper we prove the conjecture when $X$ is a complete intersection ... More
Mirror symmetry for concavex vector bundles on projective spacesApr 25 2000Jan 26 2005Let $X\subset Y$ be smooth, projective manifolds. Assume that $X$ is the zero locus of a generic section of a direct sum $V+$ of positive line bundles on $\PP^n$. Furthermore assume that the normal bundle $N_{X/Y}$ is a direct sum $V-$ of negative line ... More
Virtual Class of Zero Loci and Mirror TheoremsJul 30 2003Jan 26 2005Let $Y$ be the zero loci of a regular section of a convex vector bundle $E$ over $X$. We provide a new proof of a conjecture of Cox, Katz and Lee for the virtual class of the genus zero moduli of stable maps to $Y$. This in turn yields the expected relationship ... More
The $n$th+1 Prime Number Limit FormulasAug 04 2016Aug 08 2016A new derivation of Golomb's limit formula for generating the $n$th$+1$ prime number is presented. The limit formula is derived by extracting $p_{n+1}$ from Euler's prime product representation of the Riemann zeta function $\zeta(s)$ in the limit as $s$ ... More
Riemann's zeta function and the broadband structure of pure harmonicsMar 10 2016Let $a\in (0,1)$ and let $F_s(a)$ be the periodized zeta function that is defined as $F_s(a) = \sum n^{-s} \exp (2\pi i na)$ for $\Re s >1$, and extended to the complex plane via analytic continuation. Let $s_n = \sigma_n + it_n, \, t_n >0 $, denote the ... More
Well-Behaved Model Transformations with Model SubtypingMar 23 2017In model-driven engineering, models abstract the relevant features of software artefacts and model transformations act on them automating complex tasks of the development process. It is, thus, crucially important to provide pragmatic, reliable methods ... More
Optimal evolution models for quantum tomographyJan 08 2016The research presented in this article concerns the stroboscopic approach to quantum tomography, which is an area of science where quantum Physics and linear algebra overlap. In this article we introduce the algebraic structure of the parametric-dependent ... More
Minimal Number of Observables for Quantum Tomography of Systems with Evolution Given by Double CommutatorsJul 15 2015In this paper we analyze selected evolution models of $N-$level open quantum systems in order to find the minimal number of observables (Hermitian operators) such that their expectation values at some time instants determine the accurate representation ... More
Jordan Form and Quantum TomographyJun 01 2015In this brief article we indicate a connection between Jordan normal form of a square matrix and the stroboscopic approach to quantum tomography. We show that the index of cyclicy of a generator of evolution, which receives much attention in the stroboscopic ... More
Endomorphisms of Cuboidal Hamming Graphs, Latin Hypercuboids of Class $r$, and Mixed MDS CodesFeb 17 2016In this paper we investigate the existence of singular endomorphisms of the cuboidal Hamming graph $H(n_1,...,n_d,S)$ over the set $\left[ n_1\right]\times \left[ n_2\right]\times \cdots \times \left[ n_d\right]$, where $\left[ n\right]=\{1,...,n\}$, ... More
Semiclassical States on Lie AlgebrasOct 02 2014Mar 04 2015The effective technique for analyzing representation-independent features of quantum systems based on the semiclassical approximation (developed elsewhere), has been successfully used in the context of the canonical (Weyl) algebra of the basic quantum ... More
Fluctuation Spectra and Coarse Graining in Stochastic DynamicsNov 30 2013Fluctuations in small biological systems can be crucial for their function. Large-deviation theory characterizes such rare events from the perspective of stochastic processes. In most cases it is very difficult to directly determine the large-deviation ... More
Context unification is in PSPACEOct 16 2013Nov 08 2013Contexts are terms with one `hole', i.e. a place in which we can substitute an argument. In context unification we are given an equation over terms with variables representing contexts and ask about the satisfiability of this equation. Context unification ... More
A new approach to measurement in quantum tomographyApr 02 2015In this article we propose a new approach to quantum measurement in reference to the stroboscopic tomography. Generally, in the stroboscopic approach it is assumed that the information about the quantum system is encoded in the mean values of certain ... More
Almost reducibility and absolute continuity IJun 03 2010We consider one-frequency analytic SL(2,R) cocycles. Our main result establishes the Almost Reducibility Conjecture in the case of exponentially Liouville frequencies. Together with our earlier work, this implies that all cocycles close to constant are ... More
Semiclassical Analysis of Constrained Quantum SystemsNov 03 2009Exact procedures that follow Dirac's constraint quantization of gauge theories are usually technically involved and often difficult to implement in practice. We overview an "effective" scheme for obtaining the leading order semiclassical corrections to ... More
Exceptional and Non-crystallographic Root Systems and the Kochen-Specker TheoremJun 15 2009The Kochen-Specker theorem states that a 3-dimensional complex Euclidean space admits a finite configuration of projective lines such that the corresponding quantum observables (the orthogonal projectors) cannot be assigned with 0 and 1 values in a classically ... More
Global theory of one-frequency Schrodinger operators I: stratified analyticity of the Lyapunov exponent and the boundary of nonuniform hyperbolicityMay 25 2009We study Schrodinger operators with a one-frequency analytic potential, focusing on the transition between the two distinct local regimes characteristic respectively of large and small potentials. From the dynamical point of view, the transition signals ... More
On the spectrum and Lyapunov exponent of limit periodic Schrodinger operatorsJul 28 2008We exhibit a dense set of limit periodic potentials for which the corresponding one-dimensional Schr\"odinger operator has a positive Lyapunov exponent for all energies and a spectrum of zero Lebesgue measure. No example with those properties was previously ... More
Feedforward Neural Networks with Diffused Nonlinear Weight FunctionsOct 27 2003Mar 31 2005In this paper, feedforward neural networks are presented that have nonlinear weight functions based on look--up tables, that are specially smoothed in a regularization called the diffusion. The idea of such a type of networks is based on the hypothesis ... More
On Interference of Signals and Generalization in Feedforward Neural NetworksOct 06 2003Nov 04 2003This paper studies how the generalization ability of neurons can be affected by mutual processing of different signals. This study is done on the basis of a feedforward artificial neural network. The mutual processing of signals can possibly be a good ... More
The absolutely continuous spectrum of the almost Mathieu operatorOct 16 2008We prove that the spectrum of the almost Mathieu operator is absolutely continuous if and only if the coupling is subcritical. This settles Problem 6 of Barry Simon's list of Schr\"odinger operator problems for the twenty-first century.
On symmetries of KdV-like evolution equationsMay 22 1998Jan 09 2007The $x$-dependence of the symmetries of (1+1)-dimensional scalar translationally invariant evolution equations is described. The sufficient condition of (quasi)polynomiality in time $t$ of the symmetries of evolution equations with constant separant is ... More
Spatial embedding of neuronal trees modeled by diffusive growthMay 14 2006The relative importance of the intrinsic and extrinsic factors determining the variety of geometric shapes exhibited by dendritic trees remains unclear. This question was addressed by developing a model of the growth of dendritic trees based on diffusion-limited ... More
The Hall effect in a nonlinear strongly correlated regimeApr 11 2005I examine a model for the Hall effect in the strongly correlated regime. It emerges from an approach proposed in my previous articles [e.g. J. Phys. Chem. Solids, 65 (2004), 1507-1515; J. Geom. Phys., in press, cf. math-ph/0409023]. The model entails ... More
Smooth Siegel disks via semicontinuity: a remark on a proof of Buff and CheritatMay 19 2003Recently, Xavier Buff and Arnaud Cheritat have provided an elegant proof of the existence of quadratic Siegel disks with smooth boundary. In this short note, we show how results of Yoccoz and Risler can be used to conclude the same result. Our proof is ... More
Locally small spaces with an applicationMar 03 2019We develop the theory of locally small spaces in a new simple language and apply this simplification to re-build the theory of locally definable spaces over structures with topologies.
Degree of the Exceptional Component of the Space of Holomorphic Foliations of Degree Two and Codimension One in P3Jun 29 2018The purpose of this thesis is to obtain the degree of the exceptional component of the space of holomorphic foliations of degree two and codimension one in P3. I construct a parameter space as an explicit fiber bundle over the variety of complete flags. ... More
The Dirichlet problem for nonlocal Lévy-type operatorsFeb 03 2017May 31 2017We present the theory of the Dirichlet problem for nonlocal operators which are the generators of general pure-jump symmetric L\'evy processes whose L\'evy measures need not be absolutely continuous. We establish basic facts about the Sobolev spaces for ... More
Infinitely many local higher symmetries without recursion operator or master symmetry: integrability of the Foursov--Burgers system revisitedApr 12 2008Jan 19 2009We consider the Burgers-type system studied by Foursov, w_t &=& w_{xx} + 8 w w_x + (2-4\alpha)z z_x, z_t &=& (1-2\alpha)z_{xx} - 4\alpha z w_x + (4-8\alpha)w z_x - (4+8\alpha)w^2 z + (-2+4\alpha)z^3, (*) for which no recursion operator or master symmetry ... More
A mirror conjecture for projective bundlesSep 18 2006Oct 25 2006We propose, motivate and give evidence for a relation between the $\mathcal D$-modules of the quantum cohomology of a smooth complex projective manifold $X$ and a projective bundle $\PP(\oplus L_i)$ over $X$.
Multidimensional spectral order for selfadjoint operatorsJul 04 2019The aim of this paper is to extend the notion of the spectral order for finite families of pairwise commuting bounded and unbounded selfadjoint operators in Hilbert space. It is shown that the multidimensional spectral order $\preccurlyeq$ is preserved ... More
Improving Viterbi is Hard: Better Runtimes Imply Faster Clique AlgorithmsJul 14 2016Nov 03 2016The classic algorithm of Viterbi computes the most likely path in a Hidden Markov Model (HMM) that results in a given sequence of observations. It runs in time $O(Tn^2)$ given a sequence of $T$ observations from a HMM with $n$ states. Despite significant ... More
Quantitative analysis of nonadiabatic effects in dense H$_3$S and PH$_3$ superconductorsJul 04 2017The comparison study of high pressure superconducting state of recently synthesized H$_3$S and PH$_3$ compounds are conducted within the framework of the strong-coupling theory. By generalization of the standard Eliashberg equations to include the lowest-order ... More
Generalized Cauchy identities, trees and multidimensional Brownian motions. Part II: Combinatorial differential calculusAug 25 2007We present an analogue of the differential calculus in which the role of polynomials is played by certain ordered sets and trees. Our combinatorial calculus has all nice features of the usual calculus and has an advantage that the elements of the considered ... More
Weak mixing properties of interval exchange transformations and translation flowsMay 10 2016Let $d >1$. In this paper we show that for an irreducible permutation $\pi$ which is not a rotation, the set of $[\lambda]\in \mathbb{P}_+^{d-1}$ such that the interval exchange transformation $f([\lambda],\pi)$ is not weakly mixing does not have full ... More
Some monoids of Pisot matricesJun 11 2015We show that several monoids of non-negative integer matrices enjoy a Pisot property: each matrix in that monoid has only one eigenvalue with absolute value larger than one. These monoids come from multidimensional continued fractions, namely the fully ... More
Inverses, Powers and Cartesian products of topologically deterministic mapsOct 11 2010We show that if (X,T) is a topological dynamical system with is deterministic in the sense of Kamiski, Siemaszko and Szymaski then T^{-1} and the product system need not be determinstic in this sense. However if the product system is deterministic then ... More
Bornological quasi-metrizability in generalized topologyMay 17 2015Oct 17 2018A concept of quasi-metrizability with respect to a bornology of a generalized topological space in the sense of Delfs and Knebusch is introduced. Quasi-metrization theorems for generalized bornological universes are deduced. A uniform quasi-metrizability ... More
Degree of the exceptional component of foliations in P3Jun 13 2018The purpose of this work is to obtain the degree of the exceptional component of the space of holomorphic foliations of degree two and codimension one in P^3. We construct a parameter space as an explicit fiber bundle over the variety of complete flags. ... More
A mass, energy, enstrophy and vorticity conserving (MEEVC) mimetic spectral element discretization for the 2D incompressible Navier-Stokes equationsApr 01 2016In this work we present a mimetic spectral element discretization for the 2D incompressible Navier-Stokes equations that in the limit of vanishing dissipation exactly preserves mass, kinetic energy, enstrophy and total vorticity on unstructured grids. ... More
Asymptotic and exact expansions of heat tracesDec 15 2014We study heat traces associated with positive unbounded operators with compact inverses. With the help of the inverse Mellin transform we derive necessary conditions for the existence of a short time asymptotic expansion. The conditions are formulated ... More
Improving Viterbi is Hard: Better Runtimes Imply Faster Clique AlgorithmsJul 14 2016The classic algorithm of Viterbi computes the most likely path in a Hidden Markov Model (HMM) that results in a given sequence of observations. It runs in time $O(Tn^2)$ given a sequence of $T$ observations from a HMM with $n$ states. Despite significant ... More
Randomized Communication Without Network KnowledgeMay 13 2018Radio networks are a long-studied model for distributed system of devices which communicate wirelessly. When these devices are mobile or have limited capabilities, the system is often best modeled by the ad-hoc variant, in which the devices do not know ... More
Creation of a Deep Convolutional Auto-Encoder in CaffeDec 04 2015Apr 22 2016The development of a deep (stacked) convolutional auto-encoder in the Caffe deep learning framework is presented in this paper. We describe simple principles which we used to create this model in Caffe. The proposed model of convolutional auto-encoder ... More
Leader Election in Multi-Hop Radio NetworksMay 22 2015Mar 16 2019In this paper we present a framework for leader election in multi-hop radio networks which yield randomized leader election algorithms taking $O(\text{broadcasting time})$ in expectation, and another which yields algorithms taking fixed $O(\sqrt{\log ... More
Chaotic and non-chaotic mixed oscillations in a logistic systems with delayApr 04 2016The paper deals with the theoretical analysis of a logistic system composed of at least two elements with distributed parameters. It has been shown that such a system may generate specific oscillations in spite of the fact that the solutions of the mathematical ... More
On the Convergence and Summability of double Walsh-Fourier series of functions of bounded generalized variationFeb 06 2014The convergence of partial sums and Ces\'aro means of negative order of double Walsh-Fourier series of functions of bounded \ generalized variation is investigated.
Lebesgue measure of Feigenbaum Julia setsApr 12 2015Apr 19 2015We construct Feigenbaum quadratic polynomials whose Julia sets have positive Lebesgue measure. They provide first examples of rational maps for which the hyperbolic dimension is different from the Hausdorff dimension of the Julia set. The corresponding ... More
On the convergence of double Fourier series of functions of bounded partial generalized variationOct 16 2012The convergence of double Fourier series of functions of bounded partial $\Lambda$-variation is investigated. The sufficient and necessary conditions on the sequence $\Lambda=\{\lambda_n\}$ are found for the convergence of Fourier series of functions ... More
Small eigenvalues of the Laplacian for algebraic measures in moduli space, and mixing properties of the Teichmüller flowNov 24 2010We consider the $SL(2,R)$ action on moduli spaces of quadratic differentials. If $\mu$ is an $SL(2,R)$-invariant probability measure, crucial information about the associated representation on $L^2(\mu)$ (and in particular, fine asymptotics for decay ... More
Consistent analysis of neutral- and charged-current (anti)neutrino scattering off carbonApr 17 2013Good understanding of the cross sections for (anti)neutrino scattering off nuclear targets in the few-GeV energy region is a prerequisite for the correct interpretation of results of ongoing and planned oscillation experiments. To clarify a possible source ... More
The full renormalization horseshoe for unimodal maps of higher degree: exponential contraction along hybrid classesMay 26 2010We prove exponential contraction of renormalization along hybrid classes of infinitely renormalizable unimodal maps (with arbitrary combinatorics), in any even degree $d$. We then conclude that orbits of renormalization are asymptotic to the full renormalization ... More
Complete Set of Commuting Symmetry Operators for the Klein-Gordon Equation in Generalized Higher-Dimensional Kerr-NUT-(A)dS SpacetimesNov 29 2007Jan 08 2008We consider the Klein-Gordon equation in generalized higher-dimensional Kerr-NUT-(A)dS spacetime without imposing any restrictions on the functional parameters characterizing the metric. We establish commutativity of the second-order operators constructed ... More
Entropy and density of states from isoenergetic nonequilibrium processesAug 03 2004Apr 05 2005Two identities in statistical mechanics involving entropy differences (or ratios of density of states) at constant energy are derived. The first provides a nontrivial extension of the Jarzynski equality to the microcanonical ensemble [C. Jarzynski, Phys. ... More
Reduction of spurious velocity in finite difference lattice Boltzmann models for liquid - vapor systemsMay 09 2003The origin of the spurious interface velocity in finite difference lattice Boltzmann models for liquid - vapor systems is related to the first order upwind scheme used to compute the space derivatives in the evolution equations. A correction force term ... More
Does the Boltzmann principle need a dynamical correction?Apr 27 2002Jun 10 2004In an attempt to derive thermodynamics from classical mechanics, an approximate expression for the equilibrium temperature of a finite system has been derived [M. Bianucci, R. Mannella, B. J. West, and P. Grigolini, Phys. Rev. E 51, 3002 (1995)] which ... More
Direct detection of quantum entanglementNov 11 2001Quantum entanglement, after playing a significant role in the development of the foundations of quantum mechanics, has been recently rediscovered as a new physical resource with potential commercial applications such as, for example, quantum cryptography, ... More
Spectral functions of argon and calciumOct 20 2008Precise knowledge of the cross sections for neutrino interactions with nuclei is important not only for existing experiments but also for development of future detectors. When momentum transferred to the nucleus by the probe is high enough, the impulse ... More
Gauge Dependence of Gravitational Correction to Running of Gauge CouplingsJun 21 2006Feb 06 2007Recently an interesting idea has been put forward by Robinson and Wilczek that incorporation of quantized gravity in the framework of abelian and nonabelian gauge theories results in a correction to the running of gauge coupling and, in consequence, to ... More
The Ten Martini ProblemMar 17 2005We prove the conjecture (known as the ``Ten Martini Problem'' after Kac and Simon) that the spectrum of the almost Mathieu operator is a Cantor set for all non-zero values of the coupling and all irrational frequencies.
Weak mixing for interval exchange transformations and translation flowsJun 16 2004We show that a typical interval exchange transformation is either weakly mixing or it is an irrational rotation. We also conclude that a typical translation flow on a surface of genus $g \geq 2$ (with prescribed singularity types) is weakly mixing.
Albanian Language Identification in Text DocumentsJan 14 2019In this work we investigate the accuracy of standard and state-of-the-art language identification methods in identifying Albanian in written text documents. A dataset consisting of news articles written in Albanian has been constructed for this purpose. ... More
Pairing in Nuclear Matter and Finite NucleiDec 24 2018Effects of pairing with isospin $T=0$ and $T=1$ are systematically studied in a model, which is based on a realistic nucleon-nucleon interaction and allows to describe the transition from infinite nuclear matter to finite nuclei. Special attention is ... More
Memory equations as reduced Markov processesApr 06 2018A large class of linear memory differential equations in one dimension, where the evolution depends on the whole history, can be equivalently described as a projection of a Markov process living in a higher dimensional space. Starting with such a memory ... More
Spectral action for scalar perturbations of Dirac operatorsDec 17 2010We investigate the leading terms of the spectral action for odd-dimensional Riemannian spin manifolds with the Dirac operator perturbed by a scalar function. We calculate first two Gilkey-de Witt coefficients and make explicit calculations for the case ... More
Large Deviations for stationary probabilities of a family of continuous time Markov chains via Aubry-Mather theoryFeb 04 2014Feb 23 2014We consider a family of continuous time symmetric random walks indexed by $k\in \mathbb{N}$, $\{X_k(t),\,t\geq 0\}$. For each $k\in \mathbb{N}$ the matching random walk take values in the finite set of states $\Gamma_k=\frac{1}{k}(\mathbb{Z}/k\mathbb{Z})$ ... More
Semiclassical limits, Lagrangian states and coboundary equationsDec 25 2015Oct 28 2016Assume that $f$ is a continuous transformation $f:S^1 \to S^1$. We consider here the cases where $f$ is either the transformation $f(z)=z^2$ or $f$ is a smooth diffeomorphism of the circle $S^1$. Consider a fixed continuous potential $\tau:S^1=[0,1) \to ... More
Bornoligies, Topological Games and Function SpacesMar 27 2014In this paper, we continue the study of function spaces equipped with topologies of (strong) uniform convergence on bornologies initiated by Beer and Levi \cite{beer-levi:09}. In particular, we investigate some topological properties these function spaces ... More
Approximating the modulus of an inner functionFeb 16 2006Sep 12 2006We show that the modulus of an inner function can be uniformly approximated in the unit disk by the modulus of an interpolating Blaschke product.
Group interpretation of the spectral parameter. The case of isothermic surfacesNov 30 2016It is well known that in some cases the spectral parameter has a group interpretation. We discuss in detail the case of Gauss-Codazzi equations for isothermic surfaces immersed in $E^3$. The algebra of Lie point symmetries is 4-dimensional and all these ... More
On Bertelson-Gromov Dynamical Morse EntropyApr 18 2015In this mainly expository paper we present a detailed proof of several results contained in a paper by M. Bertelson and M. Gromov on Dynamical Morse Entropy. This is an introduction to the ideas presented in that work. Suppose $M$ is compact oriented ... More
Global Deterministic Optimization with Artificial Neural Networks EmbeddedJan 22 2018Oct 15 2018Artificial neural networks (ANNs) are used in various applications for data-driven black-box modeling and subsequent optimization. Herein, we present an efficient method for deterministic global optimization of ANN embedded optimization problems. The ... More
Semiclassical limits, Lagrangian states and coboundary equationsDec 25 2015Jan 25 2016Assume that $f$ is a continuous transformation $f:S^1 \to S^1$. We consider here the cases where $f$ is either the transformation $f(z)=z^2$ or $f$ is a smooth diffeomorphism of the circle $S^1$. Consider a fixed continuous potential $\tau:S^1=[0,1) \to ... More
Systematic uncertainties in long-baseline neutrino-oscillation experimentsSep 01 2016May 12 2017Future neutrino-oscillation experiments are expected to bring definite answers to the questions of neutrino-mass hierarchy and violation of charge-parity symmetry in the lepton sector. To realize this ambitious program it is necessary to ensure a significant ... More
L-FLAT: Logtalk Toolkit for Formal Languages and Automata TheoryDec 16 2011We describe L-FLAT, a Logtalk Toolkit for teaching Formal Languages and Automata Theory. L-FLAT supports the definition of \textsl{alphabets}, the definition of \textsl{orders} over alphabet symbols, the partial definition of \textsl{languages} using ... More
Central extensions of cotangent universal hierarchy: (2+1)-dimensional bi-Hamiltonian systemsJul 08 2008Sep 23 2008We introduce the cotangent universal hierarchy that extends the so-called universal hierarchy (as for the latter, see e.g. arXiv:nlin/0202008, arXiv:nlin/0312043 and arXiv:nlin/0310036). Then we construct a (2+1)-dimensional double central extension of ... More
Spectral representation: analyzing single-unit activity in extracellularly recorded neuronal data without spike sortingFeb 24 2005One step in the conventional analysis of extracellularly recorded neuronal data is spike sorting, which separates electrical signal into action potentials from different neurons. Because spike sorting involves human judgment, it can be subjective and ... More
Statistical properties of unimodal maps: physical measures, periodic orbits and pathological laminationsJun 10 2003In this work, we relate the geometry of chaotic attractors of typical analytic unimodal maps to the behavior of the critical orbit. Our main result is an explicit formula relating the combinatorics of the critical orbit with the exponents of periodic ... More
Initial states and decoherence of historiesMay 14 2004We study decoherence properties of arbitrarily long histories constructed from a fixed projective partition of a finite dimensional Hilbert space. We show that decoherence of such histories for all initial states that are naturally induced by the projective ... More
A precise determination of angular momentum in the black hole candidate GRO J1655-40May 04 2001We note that the recently discovered 450 Hz frequency in the X-ray flux of the black hole candidate GRO J1655-40 is in a 3:2 ratio to the previously known 300 Hz frequency of quasi-periodic oscillations (QPO) in the same source. If the origin of high ... More
Ordering of two small parameters in the shallow water wave problemJan 28 2013The classical problem of irrotational long waves on the surface of a shallow layer of an ideal fluid moving under the influence of gravity as well as surface tension is considered. A systematic procedure for deriving an equation for surface elevation ... More
The Ruelle operator for symmetric $β$-shiftsJul 10 2019Consider $m \in \mathbb{N}$ and $\beta \in (1, m + 1]$. Assume that $a\in \mathbb{R}$ can be represented in base $\beta$ using a development in series $a = \sum^{\infty}_{n = 1}x(n)\beta^{-n}$ where the sequence $x = (x(n))_{n \in \mathbb{N}}$ take values ... More
The effective potential and transshipment in thermodynamic formalism at temperature zeroAug 05 2010Denote the points in {1,2,..,r}^{Z}= {1,2,..,r}^{N} x {1,2,..,r}^{N} by ({y}^*, {x}). Given a Lipschitz continuous observable A: {1,2,..,r}^{Z} \to {R} , we define the map {G}^+: {H}\to {H} by {G}^+(\phi)({y}^*) = \sup_{\mu \in {M}_\sigma} [\int_{\{1,2,..,r\}^{N}} ... More
Evidence for a BKT transition and a pseudogap phase in three-dimensional Gross-Neveu model at nonzero temperatureOct 16 2001We present results from Monte Carlo simulations of the three-dimensional Gross-Neveu model with a U(1) chiral symmetry at nonzero temperature. We provide evidence that the model undergoes a Berezinskii-Kosterlitz-Thouless transition in accordance with ... More
Top quark mass: Latest CDF results, Tevatron combination and electroweak implicationsOct 18 2009A summary of the most up-to-date top quark mass measurements at CDF is presented. These analyses use top-antitop candidate events detected in the CDF experiment at the Tevatron collider with an integrated luminosity of up to ~3/fb. The combination of ... More
Finding Exact Values For Infinite SumsApr 12 1998This paper offers a solution method that allows one to find exact values for a large class of convergent series of rational terms. Sums of this form arise often in problems dealing with Quantum Field Theory.
Behavior of physical observables in the vicinity of the QCD critical end pointFeb 22 2007Using the SU(3) Nambu-Jona-Lasinio (NJL) model, we study the chiral phase transition at finite $T$ and $\mu_B$. Special attention is given to the QCD critical end point (CEP): the study of physical quantities, as the pressure, the entropy, the baryon ... More
A complete solution to the infinite Oberwolfach problemOct 06 2018Jan 26 2019Let $F$ be a $2$-regular graph of order $v$. The Oberwolfach problem, $OP(F)$, asks for a $2$-factorization of the complete graph on $v$ vertices in which each $2$-factor is isomorphic to $F$. Posed by G. Ringel in the 1960s, this problem is still open, ... More
Comments on "Viscosity of high crystal content melts: dependence on solid fraction"Dec 19 2005Dec 21 2005Here we propose a simple modification of the parameterisation presented in Costa (2005) [Viscosity of high crystal content melts: dependence on solid fraction, Geophys. Res. Lett., 32, 2005] which improves all the main positive features of it, yet at ... More
Viscosity of high crystal content melts: dependence on solid fractionOct 21 2005The rheological properties of suspensions containing high solid fractions are investigated. Attention is focused on viscosity of silicate and magmatic melt systems. A general empirical equation which describes the relative viscosity of suspensions as ... More
The problem of a self-gravitating scalar field with positive cosmological constantJun 19 2012Jan 15 2013We study the Einstein-scalar field system with positive cosmological constant and spherically symmetric characteristic initial data given on a truncated null cone. We prove well-posedness, global existence and exponential decay in (Bondi) time, for small ... More
Recent QCD results from the TevatronOct 10 2015Four years after the shutdown of the Tevatron proton-antiproton collider, the two Tevatron experiments, CDF and DZero, continue producing important results that test the theory of the strong interaction, Quantum Chromodynamics (QCD). The experiments exploit ... More