Results for "Paulo Purreur"

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Submillimeter - sized proximity effect in graphite and bismuthFeb 08 2019In this work, we probe the electrical properties of macroscopic graphite and bismuth in which the electrical current is injected via superconducting electrodes, few millimeters apart from each other. Results reveal the induction of a partial superconducting-like ... More
Large Social Networks can be Targeted for Viral Marketing with Small Seed SetsMay 20 2012Mar 15 2013In a "tipping" model, each node in a social network, representing an individual, adopts a behavior if a certain number of his incoming neighbors previously held that property. A key problem for viral marketers is to determine an initial "seed" set in ... More
Comparison of PBO solvers in a dependency solving domainJul 07 2010Linux package managers have to deal with dependencies and conflicts of packages required to be installed by the user. As an NP-complete problem, this is a hard task to solve. In this context, several approaches have been pursued. Apt-pbo is a package ... More
Towards a Study of Meta-Predicate SemanticsSep 20 2010We describe and compare design choices for meta-predicate semantics, as found in representative Prolog module systems and in Logtalk. We look at the consequences of these design choices from a pragmatic perspective, discussing explicit qualification semantics, ... More
Sampling Superquadric Point Clouds with NormalsFeb 14 2018Superquadrics provide a compact representation of common shapes and have been used both for object/surface modelling in computer graphics and as object-part representation in computer vision and robotics. Superquadrics refer to a family of shapes: here ... More
Proceedings Fifth International Workshop on Classical Logic and ComputationSep 09 2014Classical Logic and Computation (CL&C) 2014 is the fifth edition of this workshop series. The workshop series intends to cover all work aiming to explore computational aspects of classical logic and mathematics. Its focus is on the exploration of the ... More
Entropy and Poincaré recurrence from a geometrical viewpointSep 17 2008Jul 05 2009We study Poincar\'e recurrence from a purely geometrical viewpoint. We prove that the metric entropy is given by the exponential growth rate of return times to dynamical balls. This is the geometrical counterpart of Ornstein-Weiss theorem. Moreover, we ... More
Robust Mean Estimation with the Bayesian Median of MeansJun 04 2019The sample mean is often used to aggregate different unbiased estimates of a parameter, producing a final estimate that is unbiased but possibly high-variance. This paper introduces the Bayesian median of means, an aggregation rule that roughly interpolates ... More
The Continuous Tower of Scalar Fields as a System of Interacting Dark Matter -- Dark EnergyAug 19 2015This paper aims to introduce a new parameterisation for the coupling Q in interacting dark matter and dark energy models by connecting said models with the Continuous Tower of Scalar Fields model. Based upon the existence of a dark matter and a dark energy ... More
A continuous model of ant foraging with pheromones and trail formationFeb 23 2014We propose and numerically analyze a PDE model of ant foraging behavior. Ant foraging is a prime example of individuals following simple behavioral rules based on local information producing complex, organized and ``intelligent'' strategies at the population ... More
Non-uniform specification and large deviations for weak Gibbs measuresJun 18 2009Oct 26 2011We establish bounds for the measure of deviation sets associated to continuous observables with respect to not necessarily invariant weak Gibbs measures. Under some mild assumptions, we obtain upper and lower bounds for the measure of deviation sets of ... More
Finite-sample Guarantees for Winsorized Importance SamplingOct 25 2018Importance sampling is a widely used technique to estimate the properties of a distribution. The resulting estimator is always unbiased, but may sometimes incur huge variance. This paper investigates trading-off some bias for variance by winsorizing the ... More
Poisson quasi-Nijenhuis structures with backgroundAug 29 2008We define the Poisson quasi-Nijenhuis structures with background on Lie algebroids and we prove that to any generalized complex structure on a Courant algebroid which is the double of a Lie algebroid is associated such a structure. We prove that any Lie ... More
Unique SRB measures and transitivity for Anosov diffeomorphismsJun 01 2016Jun 03 2016We prove that every $C^2$ Anosov diffeomorphism in a compact and connected Riemannian manifold has a unique SRB and physical probability measure, whose basin of attraction covers Lebesgue almost every point in the manifold. Then, we use structural stability ... More
Unifying Functional Interpretations: Past and FutureOct 16 2014This article surveys work done in the last six years on the unification of various functional interpretations including G\"odel's dialectica interpretation, its Diller-Nahm variant, Kreisel modified realizability, Stein's family of functional interpretations, ... More
On the symmetry properties of the PT kernels and recurrence relationsOct 24 2016Perturbation Theory to Large Scale Structure Cosmology proposes corrections to the linearly evolved density contrast and velocity in terms of a series development in which all terms are integrals of powers of the linear density contrast multiplied by ... More
Holocrine Secretion and Kino Flow in Angiosperms: Their Role and Physiological Advantages in Plant Defence MechanismsFeb 20 2019Kinos are plant exudates, rich in polyphenols, produced by several angiosperms in reaction to damage. They flow out of kino veins, schizolysigenous ducts composing an anatomically distinct continuous system of tangentially anastomosing lacunae produced ... More
A version of Kac's lemma on first return times for suspension flowsNov 14 2014Nov 23 2014In this article we study the mean return times to a given set for suspension flows. In the discrete time setting, this corresponds to the classical version of Kac's lemma \cite{K} that the mean of the first return time to a set with respect to the normalized ... More
Statistical properties of generalized-Viana mapsJul 19 2012Mar 31 2013We study quadratic skew-products with parameters driven over piecewise expanding and Markov interval maps with countable many inverse branches, a generalization of the class of maps introduced by Viana. In particular we construct a class of multidimensional ... More
On a nonlocal hyperbolic conservation law arising from a gradient constraint problemFeb 06 2012In some models involving nonlinear conservation laws, physical mechanisms exist which prevent the formation of shocks. This gives rise to conservation laws with a constraint on the gradient of the solution. We approach this problem by studying a related ... More
Topological Attractors of Contracting Lorenz MapsDec 01 2016We study the non-wandering set of contracting Lorenz maps. We show that if such a map $f$ doesn't have any attracting periodic orbit, then there is a unique topological attractor. Precisely, there is a compact set $\Lambda$ such that $\omega_f(x)=\Lambda$ ... More
Controller synthesis for bisimulation equivalenceJun 06 2007Nov 22 2007The objective of this paper is to solve the controller synthesis problem for bisimulation equivalence in a wide variety of scenarios including discrete-event systems, nonlinear control systems, behavioral systems, hybrid systems and many others. This ... More
Default priors for Gaussian processesMay 27 2005Motivated by the statistical evaluation of complex computer models, we deal with the issue of objective prior specification for the parameters of Gaussian processes. In particular, we derive the Jeffreys-rule, independence Jeffreys and reference priors ... More
A nonlinear model describing a short wave long wave interaction in a viscoelastic mediumFeb 06 2012In this paper we introduce a system coupling a nonlinear Schr\"odinger equation with a system of viscoelasticity, modeling the interaction between short and long waves, acting for instance on media like plasmas or polymers. We prove the existence and ... More
Modeling ant foraging: a chemotaxis approach with pheromones and trail formationSep 11 2014Jun 22 2015We consider a continuous mathematical description of a population of ants and simulate numerically their foraging behavior using a system of partial differential equations of chemotaxis type. We show that this system accurately reproduces observed foraging ... More
On the Structure of Lorenz MapsFeb 12 2014We study the non-wandering set of $C^3$ contracting Lorenz maps $f$ with negative Schwarzian derivative. We show that if $f$ doesn't have attracting periodic orbit, then there is a unique topological attractor. Precisely, there is a transitive compact ... More
Correlation decay and recurrence estimates for some robust nonuniformly hyperbolic mapsMay 18 2008We study decay of correlations, the asymptotic distribution of hitting times and fluctuations of the return times for a robust class of multidimensional non-uniformly hyperbolic transformations. Oliveira and Viana [15] proved that there is a unique equilibrium ... More
Projection Methods for some Constrained SystemsOct 09 2011This article is concerned with a geometric tool given by a pair of projector operators defined by almost product structures on finite dimensional manifolds, polarized by a distribution of constant rank and also endowed with some geometric structures (Riemann,resp.Poisson,resp.symplectic).The ... More
Dependability in Aggregation by AveragingNov 30 2010Aggregation is an important building block of modern distributed applications, allowing the determination of meaningful properties (e.g. network size, total storage capacity, average load, majorities, etc.) that are used to direct the execution of the ... More
Second order hydrodynamics of a CFT plasma from boost invariant expansionAug 12 2008Sep 08 2008We compute finite coupling correction to a nonlinear second order hydrodynamic coefficient in the boost invariant expansion of the N=4 supersymmetric Yang-Mills plasma. The result is universal for a large class of strongly coupled four dimensional conformal ... More
$C^r$-generic Anosov diffeomorphisms have trivial centralizerJun 01 2016In the late nineties, Smale proposed a list of problems for the next century. Among these, it was conjectured that for every $r\ge 1$ a $C^r$-generic diffeomorphism has trivial centralizer. Here we provide an affirmative answer to Smale's conjecture on ... More
A Direct Proof of Schwichtenberg's Bar Recursion Closure TheoremJul 18 2016Oct 17 2016In 1979 Schwichtenberg showed that a rule-like version Spector's bar recursion of lowest type levels $0$ and $1$ is closed under system $\text{T}$. More precisely, if the functional $Y$ which controls the stopping condition of Spector's bar recursor is ... More
Charged kaon condensation in high density quark matterOct 21 2001Oct 24 2001We show that at asymptotically high densities the ``color-flavor-locked + neutral kaon condensate'' phase of QCD develops a {\it charged} kaon condensate through the Coleman-Weinberg mechanism. At densities achievable in neutron stars a charged kaon condensate ... More
Backstepping design for incremental stabilityMay 26 2010Nov 10 2010Stability is arguably one of the core concepts upon which our understanding of dynamical and control systems has been built. The related notion of incremental stability, however, has received much less attention until recently, when it was successfully ... More
Quantification of electrical charges in Kaluza Klein theory without strings of DiracJan 28 2006Apr 19 2006It is proposed a formalism of quantification of the electric charges in the Kaluza Klein theory of five dimensions and a explanation of the cause of the variation of the electromagnetic fine-structure constant in cosmological times.There is a formalism ... More
Dimension Estimation Using Random Connection ModelsNov 08 2017Information about intrinsic dimension is crucial to perform dimensionality reduction, compress information, design efficient algorithms, and do statistical adaptation. In this paper we propose an estimator for the intrinsic dimension of a data set. The ... More
Transfer of Tool Affordance and Manipulation Cues with 3D Vision DataOct 13 2017Future service robots working in human environments, such as kitchens, will face situations where they need to improvise. The usual tool for a given task might not be available and the robot will have to use some substitute tool. The robot needs to select ... More
A Note on Cohamiltonian GraphsDec 06 2017Dec 12 2017A connected graph $G$ is said cohamiltonian if it has a bond with $|E(G)|+|V(G)|+2$ edges, such bond is said cohamiltonian. A cohamiltonian bond in a connected planar graph corresponds to a hamiltonian cycle of its dual. The problem to determine if a ... More
Salem--Zygmund Inequality for Locally sub--Gaussian Random Variables and Random Trigonometric PolynomialsOct 18 2016Mar 20 2019In this paper, we provide an extension of the classic Salem--Zygmund inequality for locally sub--Gaussian random variables. As a application we study the location of the roots of a Kac polynomial. Under log--moment assumption, it is well known that the ... More
A Comparison of Methods for Cascade PredictionJun 18 2016Information cascades exist in a wide variety of platforms on Internet. A very important real-world problem is to identify which information cascades can go viral. A system addressing this problem can be used in a variety of applications including public ... More
Masses, Radii, and Equation of State of Neutron StarsMar 08 2016We summarize our current knowledge of neutron star masses and radii. Recent instrumentation and computational advances have resulted in a rapid increase in the discovery rate and precise timing of radio pulsars in binaries in the last few years, leading ... More
Toroidal boards and code coveringOct 28 2015Jul 19 2019A radius-$r$ extend ball with center in an $1$-dimensional vector subspace $V$ of $\mathbb{F}_q^3$ is the set of elements of $\mathbb{F}_q^3$ with Hamming distance to $V$ at most $r$. We define $c(q)$ as the size of a minimum covering of $\fqt$ by radius-$1$ ... More
Robust Linear Temporal LogicOct 30 2015Although it is widely accepted that every system should be robust, in the sense that "small" violations of environment assumptions should lead to "small" violations of system guarantees, it is less clear how to make this intuitive notion of robustness ... More
Mass Renormalization in Lorentz-violating Scalar Field TheoryMar 07 2014In this work we evaluate the $\gamma_{m}$ function corresponding to mass renormalization for O($N$) scalar field theory with Lorentz violation. We calculate this function up to two-loop order for a theory renormalized utilizing the counterterm method ... More
Positive Lyapunov exponents for Hamiltonian linear differential systemsApr 13 2013Jul 01 2014In the present paper we give a positive answer to some questions posed by Viana on the existence of positive Lyapunov exponents for Hamiltonian linear differential systems. We prove that there exists an open and dense set of Hamiltonian linear differential ... More
A criterion for the triviality of the centralizer for vector fields and applicationsMar 17 2019In this paper we establish a criterion for the triviality of the $C^1$-centralizer for vector fields and flows. In particular we deduce the triviality of the centralizer at homoclinic classes of $C^r$ vector fields ($r\ge 1$). Furthermore, we show that ... More
Causal Inference for Early Detection of Pathogenic Social Media AccountsJun 26 2018Aug 03 2018Pathogenic social media accounts such as terrorist supporters exploit communities of supporters for conducting attacks on social media. Early detection of PSM accounts is crucial as they are likely to be key users in making a harmful message "viral". ... More
A Schwartz type algebra for the Tangent GroupoidFeb 25 2008We construct an algebra of smooth functions over the tangent groupoid associated to any Lie groupoid. This algebra is a field of algebras over the closed interval [0, 1] which fiber at zero is the algebra of Schwartz functions over the Lie algebroid, ... More
On Various Negative TranslationsJan 28 2011Several proof translations of classical mathematics into intuitionistic mathematics have been proposed in the literature over the past century. These are normally referred to as negative translations or double-negation translations. Among those, the most ... More
Functional Interpretations of Intuitionistic Linear LogicDec 06 2010Mar 24 2011We present three different functional interpretations of intuitionistic linear logic ILL and show how these correspond to well-known functional interpretations of intuitionistic logic IL via embeddings of IL into ILL. The main difference from previous ... More
Total cohomology of solvable Lie algebras and linear deformationsMar 17 2014Given a finite dimensional Lie algebra $\mathfrak{g}$, let $\Gamma_\circ(\mathfrak{g})$ be the set of irreducible $\mathfrak{g}$-modules with non-vanishing cohomology. We prove that a $\mathfrak{g}$-module $V$ belongs to $\Gamma_\circ(\mathfrak{g})$ only ... More
Hubbert's theory and photovoltaics: the nonsense race of breaking energy-conversion recordsOct 03 2017Feb 02 2018The wide public sees solar energy as the future of mankind, and media channels quite oftenly states that our challenge is to improve efficiencies and reduce cost. However, one may point some unconvenient truth's about the physical limits we are facing, ... More
A Sampling Theorem for Rotation Numbers of Linear Processes in ${\R}^{2}$Apr 22 2014We prove an ergodic theorem for the rotation number of the composition of a sequence os stationary random homeomorphisms in $S^{1}$. In particular, the concept of rotation number of a matrix $g\in Gl^{+}(2,{\R})$ can be generalized to a product of a sequence ... More
Multifractal analysis of the irregular set for almost-additive sequences via large deviationsOct 08 2014Aug 23 2015In this paper we introduce a notion of free energy and large deviations rate function for asymptotically additive sequences of potentials via an approximation method by families of continuous potentials. We provide estimates for the topological pressure ... More
Non-Holonomic Connections Following Élie CartanOct 06 2011In this note we revisit E. Cartan's address at the 1928 International Congress of Mathematicians at Bologna, Italy. The distributions considered here will be of the same class as those considered by Cartan, a special type which we call strongly non-holonomic. ... More
A Survey of Distributed Data Aggregation AlgorithmsOct 04 2011Distributed data aggregation is an important task, allowing the decentralized determination of meaningful global properties, that can then be used to direct the execution of other applications. The resulting values result from the distributed computation ... More
A Scalable Heuristic for Viral Marketing Under the Tipping ModelSep 11 2013In a "tipping" model, each node in a social network, representing an individual, adopts a property or behavior if a certain number of his incoming neighbors currently exhibit the same. In viral marketing, a key problem is to select an initial "seed" set ... More
A Direct Proof of Schwichtenberg's Bar Recursion Closure TheoremJul 18 2016In 1979 Schwichtenberg showed that a rule-like version Spector's bar recursion of lowest type levels $0$ and $1$ is closed under system $\text{T}$. More precisely, if the functional $Y$ which controls the stopping condition of Spector's bar recursor is ... More
Unexpected behavior in 3He films and the theory of fermions in two dimensionsAug 24 2000Sep 01 2000It is shown that the recently observed and unexplained behavior for the spin diffusion in 3He films can be understood in terms of the Fermi liquid theory, provided nonperturbative effects characteristic of the two dimensions are taken into account. It ... More
On sensitivity to initial conditions and uniqueness of conjugacies for structurally stable diffeomorphismsMay 23 2016In this paper we study $C^1$-structurally stable diffeomorphisms, that is, $C^1$ Axiom A diffeomorphisms with the strong transversality condition. In contrast to the case of dynamics restricted to a hyperbolic basic piece, structurally stable diffeomorphisms ... More
Computing Robust Controlled Invariant Sets of Linear SystemsJan 04 2016We consider controllable linear discrete-time systems with perturbations and present two methods to compute robust controlled invariant sets. The first method results in an (arbitrarily precise) outer approximation of the maximal robust controlled invariant ... More
On the adoption of abductive reasoning for time series interpretationSep 19 2016Time series interpretation aims to provide an explanation of what is observed in terms of its underlying processes. The present work is based on the assumption that common classification-based approaches to time series interpretation suffer from a set ... More
Eccentric Binary Millisecond PulsarsJul 18 2009In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have ... More
Exploiting isochrony in self-triggered controlSep 27 2010Apr 26 2011Event-triggered control and self-triggered control have been recently proposed as new implementation paradigms that reduce resource usage for control systems. In self-triggered control, the controller is augmented with the computation of the next time ... More
Toroidal boards and code coveringOct 28 2015Aug 06 2018A radius-$r$ extend ball with center in an $1$-dimensional vector subspace $V$ of $\mathbb{F}_q^3$ is the set of elements of $\mathbb{F}_q^3$ with Hamming distance to $V$ at most $r$. We define $c(q)$ as the size of a minimum covering of $\fqt$ by radius-$1$ ... More
Stability boundaries of a Mathieu equation having PT symmetryDec 09 2018I've applied multiple-scale perturbation theory to a generalized complex PT-symmetric Mathieu equation in order to find the stability boundaries between bounded and unbounded solutions. The analysis suggests that the non-Hermitian parameter present in ... More
Non-Separating Cocircuits and Graphicness in MatroidsNov 25 2012Let $M$ be a 3-connected binary matroid and let $Y(M)$ be the set of elements of $M$ avoiding at least $r(M)+1$ non-separating cocircuits of $M$. Lemos proved that $M$ is non-graphic if and only if $Y(M)\neq\emp$. We generalize this result when by establishing ... More
Convergence to a Lévy process in the Skorohod $M_1$ and $M_2$ topologies for nonuniformly hyperbolic systems, including billiards with cuspsSep 18 2018Nov 23 2018We prove convergence to a Levy process for a class of dispersing billiards with cusps. For such examples, convergence to a stable law was proved by Jung & Zhang. For the corresponding functional limit law, convergence is not possible in the usual Skorohod ... More
Local up-down asymmetrically shaped equilibrium model for tokamak plasmasOct 11 2017Jun 22 2018A local magnetic equilibrium model is presented, with finite aspect ratio and up-down asymmetrically shaped cross section, that depends on eight free parameters. In contrast with other local equilibria, which provide simple magnetic-surface parametrizations ... More
A Fast Incremental Gaussian Mixture ModelJun 14 2015Jun 18 2015This work builds upon previous efforts in online incremental learning, namely the Incremental Gaussian Mixture Network (IGMN). The IGMN is capable of learning from data streams in a single-pass by improving its model after analyzing each data point and ... More
Positive Lyapunov exponents for symplectic cocyclesJul 01 2014Jun 28 2017In the present paper we give a positive answer to a question posed by Viana on the existence of positive Lyapunov exponents for symplectic cocycles. Actually, we prove that for an open and dense set of Holder symplectic cocycles over a non-uniformly hyperbolic ... More
Polytropic stars in three-dimensional spacetimeFeb 18 2003We investigate three-dimensional perfect fluid stars with polytropic equation of state, matched to the exterior three-dimensional black hole geometry of Banados, Teitelboim and Zanelli. A new class of exact solutions for a generic polytropic index is ... More
(Dual) Hoops Have Unique HalvingMar 02 2012Oct 14 2013Continuous logic extends the multi-valued Lukasiewicz logic by adding a halving operator on propositions. This extension is designed to give a more satisfactory model theory for continuous structures. The semantics of these logics can be given using specialisations ... More
An analytic index for Lie groupoidsDec 15 2006For a Lie groupoid there is an analytic index morphism which takes values in the $K-$theory of the $C^*$-algebra associated to the groupoid. This is a good invariant but extracting numerical invariants from it, with the existent tools, is very difficult. ... More
Carta a academia: por uma refundação do CNPQ e da ciência brasileiraApr 27 2017In this ``Letter'', I do introduce my point of view about the role of science in the development and organization of our societies, emphasizing that science is too far from our societies. In Brazil we follow a way similarly to that of USA and France concerning ... More
Symbolic Models for Nonlinear Control Systems: Alternating Approximate BisimulationsJul 28 2007Symbolic models are abstract descriptions of continuous systems in which symbols represent aggregates of continuous states. In the last few years there has been a growing interest in the use of symbolic models as a tool for mitigating complexity in control ... More
The structure of the environment and the complexity of rational choice proceduresSep 18 2018Sep 25 2018Beginning with Herbert Simon [10], the literature on bounded rationality has investigated in great detail how internal limitations affect an agent's choice process. The structure of the choice environment, deemed as important as internal limitations by ... More
A Direct Proof of Schwichtenberg's Bar Recursion Closure TheoremJul 18 2016Aug 15 2017In 1979 Schwichtenberg showed that the System $\text{T}$ definable functionals are closed under a rule-like version Spector's bar recursion of lowest type levels $0$ and $1$. More precisely, if the functional $Y$ which controls the stopping condition ... More
On the entropy of conservative flowsFeb 11 2010We obtain a $C^1$-generic subset of the incompressible flows in a closed three-dimensional manifold where Pesin's entropy formula holds thus establishing the continuous-time version of \cite{T}. Moreover, in any compact manifold of dimension larger or ... More
Existence, uniqueness and stability of equilibrium states for non-uniformly expanding mapsMar 18 2008We prove existence of finitely many ergodic equilibrium states for a large class of non-uniformly expanding local homeomorphisms on compact manifolds and Holder continuous potentials with not very large oscillation. No Markov structure is assumed. If ... More
Scalable and Incremental Learning of Gaussian Mixture ModelsJan 14 2017This work presents a fast and scalable algorithm for incremental learning of Gaussian mixture models. By performing rank-one updates on its precision matrices and determinants, its asymptotic time complexity is of \BigO{NKD^2} for $N$ data points, $K$ ... More
The gluing orbit property, uniform hyperbolicity and large deviations principles for semiflowsJul 14 2015Mar 21 2018In this article we introduce a gluing orbit property, weaker than specification, for both maps and flows. We prove that flows with the $C^1$-robust gluing orbit property are uniformly hyperbolic and that every uniformly hyperbolic flow satisfies the gluing ... More
Equilibrium states for non-uniformly expanding maps: decay of correlations and strong stabilityMay 24 2012Jul 19 2012We study the rate of decay of correlations for equilibrium states associated to a robust class of non-uniformly expanding maps where no Markov assumption is required. We show that the Ruelle-Perron-Frobenius operator acting on the space of Holder continuous ... More
Compactly supported analytic indices for Lie groupoidsMar 13 2008For any Lie groupoid we construct an analytic index morphism taking values in a modified $K-theory$ group which involves the convolution algebra of compactly supported smooth functions over the groupoid. The construction is performed by using the deformation ... More
JuliBootS: a hands-on guide to the conformal bootstrapDec 12 2014We introduce {\tt JuliBootS}, a package for numerical conformal bootstrap computations coded in {\tt Julia}. The centre-piece of {\tt JuliBootS} is an implementation of Dantzig's simplex method capable of handling arbitrary precision linear programming ... More
Relaxation time of a CFT plasma at finite couplingJun 04 2008Following recent formulation of second order relativistic viscous hydrodynamics for conformal fluids, we compute finite coupling corrections to the relaxation time of N=4 supersymmetric Yang-Mills plasma. The result is expected to be universal for any ... More
Metric operators for non-Hermitian quadratic su(2) HamiltoniansDec 01 2010Jun 13 2011A class of non-Hermitian quadratic su(2) Hamiltonians having an anti-linear symmetry is constructed. This is achieved by analysing the possible symmetries of such systems in terms of automorphisms of the algebra. In fact, different realisations for this ... More
Ion and neutral molecules in the W43-MM1(G30.79 FIR 10) infalling clumpSep 17 2011The high mass star forming clump W43-MM1 has been mapped in N$_{2}$H$^{+}(4 \rightarrow 3)$, C$^{18}$O$(3 \rightarrow 2)$, SiO$(8 \rightarrow 7)$, and in a single pointing in DCO$^{+}(5 \rightarrow 4)$ towards the center of the clump. Column densities ... More
Aharonov-Bohm effect and nucleon-nucleon phase shifts on the latticeFeb 14 2004We propose a method for the lattice QCD computation of nucleon-nucleon low-energy interactions. It consists in simulating QCD in the background of a ''electromagnetic" field whose potential is non-vanishing, but whose field strength is zero. By tuning ... More
Solving the mystery of IapetusApr 29 2005Jul 19 2007For a much better-founded theory, check Wing Ip, GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L16203, doi:10.1029/2005GL025386, 2006 (see also
On the localization of the roots for Kac polynomialsJul 30 2018In this paper, under heavy-tail assumption on the independent and identically distributed non-degenerated random coefficients $\xi_0,\ldots,\xi_{n-1}$ of the Kac polynomial $G_n(z)=\sum_{k=0}^{n-1}\xi_kz^k$, with probability approaching to one we locate ... More
On the localization of the roots of random polynomial with exponential moments and random circulant matricesOct 18 2016Apr 15 2018It is well known that under log--moment assumption on the i.i.d. coefficients of a random polynomial, its roots are uniformly gathering around the unit circle. However, the classical results do not provide any clue about how the roots are moving to the ... More
Proposing a Experimental Astronomical Test to the Existence of the Quantum StringsApr 19 2006It is proposed a model of Kaluza Klein that does make the quantification of the electric charges without magnetic monopoles. This model of Kaluza Klein allows to calculate de radius of compactation proposed for Klein. The model is of Kaluza Klein, but ... More
Convergence of a numerical scheme for a coupled Schrödinger--KdV systemFeb 06 2012We prove the convergence in a strong norm of a finite difference semi-discrete scheme approximating a coupled Schr\"odinger--KdV system on a bounded domain. This system models the interaction of short and long waves. Since the energy estimates available ... More
A Game-Theoretic Computational Interpretation of Proofs in Classical AnalysisApr 24 2012It has been shown that a functional interpretation of proofs in mathematical analysis can be given by the product of selection functions, a mode of recursion that has an intuitive reading in terms of the computation of optimal strategies in sequential ... More
Detection Performance with Many Antennas Available for Bandwidth-Efficient Uplink Transmission in MU-MIMO SystemsNov 14 2016This paper is concerned with SC/FDE for bandwidth-efficient uplink block transmission, with QAM schemes, in a MU MIMO system. The number of BS receiver antennas is assumed to be large, but not necessarily much larger than the overall number of transmitter ... More
Contractible edges in 3-connected graphs that preserve a minorJul 21 2015Oct 03 2015Let $G$ be a $3$-connected graph with a $3$-connected (or sufficiently small) simple minor $H$. We establish that $G$ has a forest $F$ with at least $\left\lceil(|G|-|H|+1)/2\right\rceil$ edges such that $G/e$ is $3$-connected with an $H$-minor for each ... More
Equações diferenciais pantográficas: retardo proporcionalMay 24 2014We present initially the motivation, definition and basic properties of differential equations with proportional delay. In the last Section we present open problems.
Estimation of Local Degree Distributions via Local Weighted Averaging and Monte Carlo Cross-ValidationFeb 26 2018Owing to their capability of summarising interactions between elements of a system, networks have become a common type of data in many fields. As networks can be inhomogeneous, in that different regions of the network may exhibit different topologies, ... More
Two problems in Partial Differential Equations (in Portuguese)Jan 13 2018In this work, we examine two important problems in the theory of nonlinear PDEs. In Part I, we propose and solve a more general and complete version of the celebrated Leray's problem for the incompressible Navier-Stokes equations in $ \mathbb{R}^{3} \!$, ... More