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Anomalous Non-linear Optical Response Of Graphene Near Phonon ResonancesJan 31 2017In this work we probe the third-order non-linear optical property of graphene, hexagonal boron nitride and their heterostructure by the use of coherent anti-Stokes Raman Spectroscopy. When the energy difference of the two input fields match the phonon ... More

Early Fusion Strategy for Entity-Relationship RetrievalJul 27 2017Oct 19 2017We address the task of entity-relationship (E-R) retrieval, i.e, given a query characterizing types of two or more entities and relationships between them, retrieve the relevant tuples of related entities. Answering E-R queries requires gathering and ... More

Entity-Relationship Search over the WebOct 08 2018Entity-Relationship (E-R) Search is a complex case of Entity Search where the goal is to search for multiple unknown entities and relationships connecting them. We assume that a E-R query can be decomposed as a sequence of sub-queries each containing ... More

The failure of the Classical Nucleation Theory at low temperatures resolvedFeb 08 2019A relevant observation about crystal nucleation kinetics in glass-forming substances has been a matter of intense debate for several decades. The Classical Nucleation Theory (CNT) allegedly fails to describe the temperature dependence of the homogeneous ... More

Learning Word Embeddings from the Portuguese Twitter Stream: A Study of some Practical AspectsSep 04 2017This paper describes a preliminary study for producing and distributing a large-scale database of embeddings from the Portuguese Twitter stream. We start by experimenting with a relatively small sample and focusing on three challenges: volume of training ... More

Rigidity of marginally outer trapped 2-spheresApr 25 2015Jun 04 2015In a recent work, Galloway [9] proved a local foliation theorem by MOTSs for a 3-dimensional initial data set $(M,g,K)$ with mean curvature $\tau\le0$ in a 4-dimensional spacetime $(\overline M,\overline g)$ when (under suitable assumptions) $M$ has a ... More

Reproducible research using biomodelsJun 04 2018Like other types of computational research, modeling and simulation of biological processes (biomodels) is still largely communicated without sufficient detail to allow independent reproduction of results. But reproducibility in this area of research ... More

The Influence of the Dynamic State of Galaxy Clusters on Segregation Phenomena and Velocity Dispersion ProfilesDec 03 2018In this work we investigate the influence of the dynamic state of galaxy clusters on segregation effects and velocity dispersion profiles (VDPs) for a sample of 111 clusters extracted from SDSS-DR7. We find that 73 clusters have Gaussian (G) velocity ... More

Multiple-antenna fading coherent channels with arbitrary inputs: Characterization and optimization of the reliable information transmission rateOct 25 2012We investigate the constrained capacity of multiple-antenna fading coherent channels, where the receiver knows the channel state but the transmitter knows only the channel distribution, driven by arbitrary equiprobable discrete inputs in a regime of high ... More

Layering Data Structures over Skip Graphs for Increased NUMA LocalityFeb 19 2019We describe an approach for blackbox concurrency based on layering user-provided, sequential data structures over concurrent skip graph variants for increased NUMA locality. We implement sets, maps, and priority queues, although our approach is potentially ... More

A consistent measure for lattice Yang-MillsNov 08 2017The construction of a consistent measure for Yang-Mills is a precondition for an accurate formulation of non-perturbative approaches to QCD, both analytical and numerical. Using projective limits as subsets of Cartesian products of homomorphisms from ... More

Stochastic solutions of nonlinear PDE's and an extension of superprocessesSep 14 2012Stochastic solutions provide new rigorous results for nonlinear PDE's and, through its local non-grid nature, are a natural tool for parallel computation. There are two different approaches for the construction of stochastic solutions: MacKean's and superprocesses. ... More

The deformation-stability fundamental length and deviations from cDec 14 2011The existence of a fundamental length (or fundamental time) has been conjectured in many contexts. However, the "stability of physical theories principle" seems to be the one that provides, through the tools of algebraic deformation theory, an unambiguous ... More

Universal families and quantum control in infinite dimensionsFeb 03 2009In a topological space, a family of continuous mappings is called universal if its action, in at least one element of the space, is dense. If the mappings are unitary or trace-preserving completely positive, the notion of universality is closely related ... More

The fractional volatility model: An agent-based interpretationJun 26 2007Aug 29 2007Based on criteria of mathematical simplicity and consistency with empirical market data, a model with volatility driven by fractional noise has been constructed which provides a fairly accurate mathematical parametrization of the data. Here, some features ... More

On some dynamical problems related to boundary layer turbulenceMar 30 1999A number of simplified dynamical problems is studied in an attempt to clarify some of the mechanisms leading to turbulence and the existing proposals to control this transition. A simplified set of boundary layer equations displays a solution that corresponds ... More

Characterizing self-organization and coevolution by ergodic invariantsMar 25 1999In addition to the emergent complexity of patterns that appears when many agents come in interaction, it is also useful to characterize the dynamical processes that lead to their self-organization. A set of ergodic invariants is identified for this purpose, ... More

Searching for the deformation-stability fundamental length (or fundamental time)Nov 23 2011The existence of a fundamental length (or fundamental time) has been conjectured in many contexts. However, the "stability of physical theories principle" seems to be the one that provides, through the tools of algebraic deformation theory, an unambiguous ... More

Some consequences of a noncommutative space-time structureJun 01 2004The existence of a fundamental length (or fundamental time) has been conjecture in many contexts. Here one discusses some consequences of a fundamental constant of this type, which emerges as a consequence of deformation-stability considerations leading ... More

Collision states and scar effects in charged three-body problemsMay 22 1997Semiclassical methods form a bridge between classical systems and their quantum counterparts. An interesting phenomenon discovered in this connection is the scar effect, whereby energy eigenstates display enhancement structures resembling the path of ... More

Social-aware Forwarding in Opportunistic Wireless Networks: Content Awareness or Obliviousness?Jul 31 2014With the current host-based Internet architecture, networking faces limitations in dynamic scenarios, due mostly to host mobility. The ICN paradigm mitigates such problems by releasing the need to have an end-to-end transport session established during ... More

Tabula: A Language to Model Spreadsheet TablesJul 10 2017Spreadsheets provide a flexible and easy to use software development environment, but that leads to error proneness. Work has been done to prevent errors in spreadsheets, including using models to specify distinct parts of a spreadsheet as it is done ... More

Singular Riemannian foliations and their quadratic basic polynomialsNov 07 2016We present a new link between the Invariant Theory of infinitesimal singular Riemannian foliations and Jordan algebras. This, together with an inhomogeneous version of Weyl's First Fundamental Theorems, provides a characterization of the recently discovered ... More

Replica Bounds by Combinatorial Interpolation for Diluted Spin SystemsAug 08 2017Jan 17 2018In two papers Franz, Leone and Toninelli proved bounds for the free energy of diluted random constraints satisfaction problems, for a Poisson degree distribution [5] and a general distribution [6]. Panchenko and Talagrand [16] simplified the proof and ... More

The geometry of noncommutative space-timeOct 18 2017Stabilization, by deformation, of the Poincar\'{e}-Heisenberg algebra requires both the introduction of a fundamental lentgh and the noncommutativity of translations which is associated to the gravitational field. The noncommutative geometry structure ... More

Lipschitz contact equivalence and real analytic functionsJan 17 2018We study the properties of the a complete invariant of the analytic function of two variables with respect to the Lipschitz contact equivalence. This invariant is called pizza. We prove that the pizza of real analytic functions has some continuity properties. ... More

Tight Bounds for Connectivity and Set Agreement in Byzantine Synchronous SystemsMay 16 2015Aug 26 2015In this paper, we show that the protocol complex of a Byzantine synchronous system can remain $(k - 1)$-connected for up to $\lceil t/k \rceil$ rounds, where $t$ is the maximum number of Byzantine processes, and $t \ge k \ge 1$. Protocol complex connectivity ... More

Model Selection Consistency for Cointegrating RegressionsApr 29 2011Oct 10 2011We study the asymptotic properties of the adaptive Lasso in cointegration regressions in the case where all covariates are weakly exogenous. We assume the number of candidate I(1) variables is sub-linear with respect to the sample size (but possibly larger) ... More

The degree of the generators of the canonical ring of surfaces with p_g=0Mar 06 1997It is shown that the canonical ring of a minimal surface of general type with $p_g=0, K^2\geq 2$ is generated by its elements of degree lesser or equal to 5, provided $|2K|$ has no fixed components, and that this bound can be lowered to 4 under the assumption ... More

Proceedings of the 5th International Workshop on Software Engineering Methods in Spreadsheets (SEMS'18)Aug 28 2018Proceedings of the 5th International Workshop on Software Engineering Methods in Spreadsheets (SEMS'18), held on October 1st, 2018, in Lisbon, Portugal, and co-located with the 2018 IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC). ... More

Tuning the pn junction at a metal-graphene interface via H2 exposureMar 15 2016Combining experiment and theory, we investigate how the naturally created heterojunction at a graphene and metallic contact is modulated via interaction with molecular hydrogen (H2). Due to electrostatic interaction, a Cr/Au electrode induces a pn junction ... More

Electron-photon interaction in a quantum point contact coupled to a microwave resonatorApr 13 2016We study a single-mode cavity weakly coupled to a voltage-biased quantum point contact. In a perturbative analysis, the lowest order predicts a thermal state for the cavity photons, driven by the emission noise of the conductor. The cavity is thus emptied ... More

Severi type inequalities for irregular surfaces with ample canonical classApr 06 2009Let S be a smooth minimal complex projective surface of maximal Albanese dimension. Under the assumption that the canonical class of S is ample and the irregularity of S, q(S), is greater or equal to 5 we show that K^2>= 4\chi(S)+(10/3)q(S)-8, thus improving ... More

Non-commutative space-time and the uncertainty principleJun 12 2001The full algebra of relativistic quantum mechanics (Lorentz plus Heisenberg) is unstable. Stabilization by deformation leads to a new deformation parameter $\epsilon \ell ^{2}$, $\ell $ being a length and $\epsilon$ a $\pm$ sign. The implications of the ... More

Form Factors in the Heavy Quark and Chiral Limit: Pole dominance in $\bar B\to πe \barν_e$Jan 21 1994Jan 23 1994It is shown that the form factors in the semileptonic decay of ground state heavy mesons to light pseudoscalar mesons are dominated by the vector meson pole at all momentum transfers. First, the general approaches to modeling form factors in terms of ... More

Segregation assisted grain boundary precipitation in a model Al-Zn-Mg-Cu alloyJul 11 2018Understanding the composition evolution of grain boundaries and grain boundary precipitation at near-atomic scale in aluminum alloys is crucial to tailor mechanical properties and to increase resistance to corrosion and stress corrosion cracking. Here, ... More

Godeaux surfaces with an Enriques involution and some stable degenerationsFeb 16 2015We give an explicit description of the Godeaux surfaces that admit an involution such that the quotient surface is birational to an Enriques surface; these surfaces give a 6-dimensional unirational irreducible subset of the moduli space of surfaces of ... More

Atomic-scale grain boundary engineering to overcome hot-cracking in additively-manufactured superalloysMay 23 2019Aug 01 2019There are still debates regarding the mechanisms that lead to hot cracking in parts build by additive manufacturing (AM) of non-weldable Ni-based superalloys. This lack of in-depth understanding of the root causes of hot cracking is an impediment to designing ... More

Long range dependence and the dynamics of exploited fish populationsJun 04 2014Long range dependence or long memory is a feature of many processes in the natural world, which provides important insights on the underlying mechanisms that generate the observed data. The usual tools available to characterize the phenomenon are mostly ... More

Dynamics of conservative Bykov cycles: tangencies, generalized cocoon bifurcations and elliptic solutionsNov 27 2015This paper presents a mechanism for the coexistence of hyperbolic and non-hyperbolic dynamics arising in a neighbourhood of a conservative Bykov cycle where trajectories turn in opposite directions near the two saddle-foci. We show that {within the class ... More

On the Dirac OscillatorJul 08 2007Dec 18 2007In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra $C\ell_7.$ The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit.

Evolution of Anisotropies in Eddington-Born-Infeld CosmologyJun 23 2008Sep 16 2008Recently a Born-Infeld action for dark energy and dark matter that uses additional affine connections was proposed. At background level, it was shown that the new proposal can mimic the standard cosmological evolution. In Bianchi cosmologies, contrary ... More

Fano-like Anti-resonances in Nanomechanical and Optomechanical SystemsAug 08 2008Feb 11 2009We study a resonator coupled to a generic detector and calculate the noise spectra of the two sub-systems. We describe the coupled system by a closed, linear, set of Langevin equations and derive a general form for the finite frequency noise of both the ... More

Anisotropic Cosmological Constant and the CMB Quadrupole AnomalyAug 08 2007Jan 25 2008There are evidences that the cosmic microwave background (CMB) large-angle anomalies imply a departure from statistical isotropy and hence from the standard cosmological model. We propose a LCDM model extension whose dark energy component preserves its ... More

Formation of a Black Hole in the DarkMay 12 2003We show that the black hole in the x-ray binary Cygnus X-1 was formed in situ and did not receive an energetic trigger from a nearby supernova. The progenitor of the black hole had an initial mass greater than 40 solar masses and during the collapse to ... More

Nonlocal games, synchronous correlations, and Bell inequalitiesJul 19 2017Sep 21 2017A nonlocal game with a synchronous correlation is a natural generalization of a function between two finite sets, and has recently appeared in the context of quantum graph homomorphisms. In this work we examine analogues of Bell's inequalities for synchronous ... More

Algebraic and Dirac-Hestenes Spinors and Spinor FieldsDec 10 2002May 31 2005Almost all presentations of Dirac theory in first or second quantization in Physics (and Mathematics) textbooks make use of covariant Dirac spinor fields. An exception is the presentation of that theory (first quantization) offered originally by Hestenes ... More

Semiglobal exponential stabilization of nonautonomous semilinear parabolic-like systemsMar 18 2019It is shown that an explicit oblique projection nonlinear feedback controller is able to stabilize semilinear parabolic equations, with time-dependent dynamics and with a polynomial nonlinearity. The actuators are typically modeled by a finite number ... More

A Neural Network Approach to ECG DenoisingDec 20 2012We propose an ECG denoising method based on a feed forward neural network with three hidden layers. Particulary useful for very noisy signals, this approach uses the available ECG channels to reconstruct a noisy channel. We tested the method, on all the ... More

The $q$-Deformed Wigner Oscillator in Quantum MechanicsAug 28 2003Using a super-realization of the Wigner-Heisenberg algebra a new realization of the q-deformed Wigner oscillator is implemented.

The Quantum Mechanics SUSY Algebra: An Introductory ReviewMay 02 2002Sep 12 2002Starting with the Lagrangian formalism with N=2 supersymmetry in terms of two Grassmann variables in Classical Mechanics, the Dirac canonical quantization method is implemented. The N=2 supersymmetry algebra is associated to one-component and two-component ... More

"Non-renormalization" without supersymmetryNov 03 2006Dec 19 2006The g_{YM} perturbed, non supersymmetric extension of the dual single matrix description of 1/2 BPS states, within the Hilbert space reduction to the oscillator subsector associated with chiral primaries is considered. This matrix model is described in ... More

Morphisms in categories of nonlocal gamesOct 23 2018Synchronous correlations provide a class of nonlocal games that behave like functions between finite sets. In this work we examine categories whose morphisms are games with synchronous classical, quantum, or general nonsignaling correlations. In particular, ... More

Strange attractors and non wandering domains near a homoclinic cycle to a bifocusJan 11 2018Jun 06 2018In this paper, we explore the three-dimensional chaotic set near a homoclinic cycle to a hyperbolic bifocus at which the vector field has negative divergence. If the invariant manifolds of the bifocus satisfy a non-degeneracy condition, a sequence of ... More

Asymptotic stability of Oseen vortices for a density-dependent incompressible viscous fluidNov 20 2006In the analysis of the long-time behaviour of two-dimensional incompressible viscous fluids, Oseen vortices play a major role as attractors of any homogeneous solution with integrable initial vorticity. As a first step in the study of the density-dependent ... More

Optimal Control and Numerical Optimization Applied to Epidemiological ModelsJan 29 2014The relationship between epidemiology, mathematical modeling and computational tools allows to build and test theories on the development and battling of a disease. This PhD thesis is motivated by the study of epidemiological models applied to infectious ... More

Preheating in Generalized Einstein TheoriesFeb 08 1999Jul 14 1999We study the preheating scenario in Generalized Einstein Theories, considering a class of such theories which are conformally equivalent to those of an extra field with a modified potential in the Einstein frame. Resonant creation of bosons from oscillating ... More

Convergence Rates for Mixture-of-ExpertsOct 10 2011Nov 01 2011In mixtures-of-experts (ME) model, where a number of submodels (experts) are combined, there have been two longstanding problems: (i) how many experts should be chosen, given the size of the training data? (ii) given the total number of parameters, is ... More

The order of finite algebraic fundamental groups of surfaces with K^2<=3χ-2May 29 2006We study the structure of the algebraic fundamental group for minimal surfaces of general type S satisfying K_S^2<=3\chi-2$ and not having any irregular etale cover. We show that, if K_S^2<=3\chi-2, then then the algebraic fundamental group of S has order ... More

A dichotomy in area-preserving reversible mapsMar 14 2014In this paper we study R-reversible area-preserving maps f on a two-dimensional Riemannian closed manifold M, i.e. diffeomorphisms f such that Ro f=f^{-1}o R where R is an isometric involution on M. We obtain a C1-residual subset where any map inside ... More

La conjecture $ε$ locale de Kato en dimension $2$Feb 18 2017Feb 16 2018We show an Iwasawa functional equation for a two dimensional $p$-adic representation of the absolute Galois group of $\mathbf{Q}_p$. This allows us to complete Nakamura's proof of Kato's local $\epsilon$-conjecture in dimension $2$.

Parametrization for a class of Rauzy FractalSep 03 2014Aug 21 2017In this paper, we study a class of Rauzy fractals ${\mathcal R}_a$ given by the polynomial $x^3- ax^2+x-1$ where $a \geq 2$ is an integer. In particular we give explicitly an automaton that generates the boundary of ${\mathcal R}_a$ and using an exotic ... More

Large N Spectrum of two Matrices in a Harmonic Potential and BMN energiesOct 28 2005The large N spectrum of the quantum mechanical hamiltonian of two hermitean matrices in a harmonic potential is studied in a framework where one of the matrices is treated exactly and the other is treated as a creation operator impurity in the background ... More

Electromagnetic Dualities on Noncommutative Space-Time and Symplectic FormalismsNov 07 2006In this thesis we analyze extensions of classical electromagnetic dualities to the noncommutative (NC) 3D and 4D space-times. It is known that the noncomutativity parameter theta becomes its Hodge dual *theta through the NC 4D electromagnetic duality ... More

Elliptical galaxies kinematics within general relativity with renormalization group effectsMar 10 2012Sep 04 2012The renormalization group framework can be applied to Quantum Field Theory on curved space-time, but there is no proof whether the beta-function of the gravitational coupling indeed goes to zero in the far infrared or not. In a recent paper we have shown ... More

Sheaves as modulesNov 28 2007Jan 28 2008We revisit sheaves on locales by placing them in the context of the theory of quantale modules. The local homeomorphisms $p:X\to B$ are identified with the Hilbert $B$-modules that are equipped with a natural notion of basis. The homomorphisms of these ... More

A spinorial approach to constant scalar curvature hypersurfaces in pseudo-hyperbolic manifoldsJun 04 2018Using spinorial techniques, we prove, for a class of pseudo-hyperbolic ambient manifolds, a Heintze-Karcher type inequality. We then use this inequality to show an Alexandrov type theorem in such spaces.

Boundary crisis for degenerate singular cyclesSep 13 2016The term boundary crisis refers to the destruction or creation of a chaotic attractor when parameters vary. The locus of a boundary crisis may contain regions of positive Lebesgue measure marking the transition from regular dynamics to the chaotic regime. ... More

Intervalley scattering of graphene massless Dirac fermions at 3-periodic grain boundariesJul 12 2016We study how low-energy charge carriers scatter off periodic and linear graphene grain boundaries oriented along the zigzag direction with a periodicity three times greater than that of pristine graphene. These defects map the two Dirac points into the ... More

Symmetries for Julia sets of rational mapsFeb 25 2019Since the 1980s, much progress has been done in completely determining which functions share a Julia set. The polynomial case was completely solved in 1995, and it was shown that the symmetries of the Julia set play a central role in answering this question. ... More

On the Effectiveness of Punishments in a Repeated Epidemic Dissemination GameAug 29 2013Aug 30 2013This work uses Game Theory to study the effectiveness of punishments as an incentive for rational nodes to follow an epidemic dissemination protocol. The dissemination process is modeled as an infinite repetition of a stage game. At the end of each stage, ... More

On the Range of Equilibria Utilities of a Repeated Epidemic Dissemination Game with a MediatorJul 23 2014Oct 19 2014We consider eager-push epidemic dissemination in a complete graph. Time is divided into synchronous stages. In each stage, a source disseminates $\nu$ events. Each event is sent by the source, and forwarded by each node upon its first reception, to $f$ ... More

Accountability in Dynamic NetworksFeb 11 2016May 12 2016We take a game theoretical approach to determine necessary and sufficient conditions under which we can persuade rational agents to exchange messages in pairwise exchanges over links of a dynamic network, by holding them accountable for deviations with ... More

Regression Adjustment for Noncrossing Bayesian Quantile RegressionFeb 04 2015A two-stage approach is proposed to overcome the problem in quantile regression, where separately fitted curves for several quantiles may cross. The standard Bayesian quantile regression model is applied in the first stage, followed by a Gaussian process ... More

The trace formulas yield the inverse metric formulaMay 06 1998May 03 2000It is a well-known fact that the first and last non-trivial coefficients of the characteristic polynomial of a linear operator are respectively its trace and its determinant. This work shows how to compute recursively all the coefficients as polynomial ... More

On the dynamics of Translated Cone Exchange TransformationsSep 14 2018Jan 29 2019In this paper we investigate translated cone exchange transformations, a new family of piecewise isometries and renormalize its first return map to a subset of its partition. As a consequence we show that the existence of an embedding of an interval exchange ... More

Exponential Decay and Lack of Analyticity for the System of the Kirchhoff Love Plates and Membrane Like Electric Network Equation with Fractional Partial DampingAug 13 2019The emphasis in this paper is on the Coupled System of a Kirchhoff Love Plate Equation with the Equation of a Membrane like Electrical Network, where the coupling is of higher order given by the Laplacian of the displacement velocity $-\gamma\Delta u_t$ ... More

Equilibrium States in Numerical Argumentation NetworksAug 28 2014Mar 18 2015Given an argumentation network with initial values to the arguments, we look for algorithms which can yield extensions compatible with such initial values. We find that the best way of tackling this problem is to offer an iteration formula that takes ... More

Killing Vector Fields, Maxwell Equations and Lorentzian SpacetimesJan 23 2008Aug 13 2008In this paper we first analyze the structure of Maxwell equations in a Lorentzian spacetime where the potential A is proportional to 1-form K physically equivalent to a Killing vector field (supposed to exist). We show that such A obeys the Lorenz gauge ... More

Loop Space Hamiltonians And Field Theory Of Non-Critical StringsDec 14 1993Dec 15 1993We consider the loop space representation of multi-matrix models. Explaining the origin of a time variable through stochastic quantization we make contact with recent proposals of Ishibashi and Kawai. We demonstrate how collective field theory with its ... More

Linear Asymptotic Stability and Modulation Behavior near Periodic Waves of the Korteweg-de Vries EquationJun 19 2017We provide a detailed study of the dynamics obtained by linearizing the Korteweg-de Vries equation about one of its periodic traveling waves, a cnoidal wave. In a suitable sense, linearly analogous to space-modulated stability, we prove global-in-time ... More

Sectional curvature and Weitzenböck formulaeAug 29 2017We establish an algebraic characterization of sectional curvature bounds $\sec\geq k$ and $\sec\leq k$ involving the curvature term in the Weitzenb\"ock formulae for symmetric $p$-tensors. This characterization is further clarified by means of a symmetric ... More

Key Stakeholders' Value Propositions for Feature Selection in Software-intensive Products: An Industrial Case StudyOct 30 2018Numerous software companies are adopting value-based decision making. However, what does value mean for key stakeholders making decisions? How do different stakeholder groups understand value? Without an explicit understanding of what value means, decisions ... More

Numerical Godeaux surfaces with an involutionJan 31 2005Minimal algebraic surfaces of general type with the smallest possible invariants have geometric genus zero and K^2=1 and are usually called "numerical Godeaux surfaces". Although they have been studied by several authors, their complete classification ... More

Kneading Theory for Triangular MapsJan 07 2003Feb 28 2003The main purpose of this paper is to present a kneading theory for two-dimensional triangular maps. This is done by defining a tensor product between the polynomials and matrices corresponding to the one-dimensional basis map and fiber map. We also define ... More

Topological Classification and Finite Determinacy of knotted mapsNov 02 2018We show that the knot type of the link of a real analytic map germ with isolated singularity $f\colon(\mathbb{R}^2,0)\to(\mathbb{R}^4,0)$ is a complete invariant for $C^0$-$\mathscr A$-equivalence. Moreover, we also prove that isolated instability implies ... More

The star-center of the quaternionic numerical rangeJul 31 2019In this paper we prove that the quaternionic numerical range is always star-shaped and its star-center is given by the equivalence classes of the star-center of the bild. We determine the star-center of the bild, and consequently of the numerical range, ... More

Small-world of communities: communication and correlation of the meta-networkDec 02 2008Aug 27 2009Given a network and a partition in n communities, we address the issues ``how communities influence each other'' and ``when two given communities do communicate''. We prove that, for a small-world network, among communities, a simple superposition principle ... More

Effective field theory for models defined over small-world networks. First and second order phase transitionsSep 03 2008We present an effective field theory method to analyze, in a very general way, models defined over small-world networks. Even if the exactness of the method is limited to the paramagnetic regions and to some special limits, it provides, yielding a clear ... More

Portfolios and the market geometryAug 20 2011A geometric analysis of the time series of returns has been performed in the past and it implied that the most of the systematic information of the market is contained in a space of small dimension. Here we have explored subspaces of this space to find ... More

A data-reconstructed fractional volatility modelFeb 01 2006Jun 26 2007Based on criteria of mathematical simplicity and consistency with empirical market data, a stochastic volatility model is constructed, the volatility process being driven by fractional noise. Price return statistics and asymptotic behavior are derived ... More

Quantum sensitive dependenceMay 23 2002Wave functions of bounded quantum systems with time-independent potentials, being almost periodic functions, cannot have time asymptotics as in classical chaos. However, bounded quantum systems with time-dependent interactions, as used in quantum control, ... More

A dynamical characterization of the small world phaseApr 26 2002Small-world (SW) networks have been identified in many different fields. Topological coefficients like the clustering coefficient and the characteristic path length have been used in the past for a qualitative characterization of these networks. Here ... More

Non-commutative time-frequency tomographyDec 12 1997The characterization of non-stationary signals requires joint time and frequency information. However, time (t) and frequency (omega) being non-commuting variables there cannot be a joint probability density in the (t,omega) plane and the time-frequency ... More

Scalar charges and pulsar-timing observables in the presence of nonminimally coupled scalar fieldsMar 27 2019Pulsar-timing has become a celebrated tool for probing modifications to General Relativity in the strong-field surroundings of neutron stars. Here we investigate whether scalar-tensor theories that incorporate a nonminimally coupled scalar degree of freedom ... More

Swimming in spacetime: the view from a Fermi observerJul 27 2017Dec 18 2017An extended test body moving in a curved spacetime does not typically follow a geodesic, because of forces that arise from couplings between its multipole moments and the ambient curvature. An illustration of this fact was provided by Wisdom, who showed ... More

Option pricing with fractional volatilityApr 28 2004Based on empirical market data, a stochastic volatility model is proposed with volatility driven by fractional noise. The model is used to obtain a risk-neutrality option pricing formula and an option pricing equation.

Assessment Model for Opportunistic RoutingJun 02 2014This paper proposes an assessment model, based on a new taxonomy, which comprises an evaluation guideline with performance metrics and experimental setup to aid designers in evaluating solutions through fair comparisons. Simulation results are provided ... More

On chaos of a cubic $p$-adic dynamical systemAug 23 2006In the paper we describe basin of attraction of the $p$-adic dynamical system $f(x)=x^3+ax^2$. Moreover, we also describe the Siegel discs of the system, since the structure of the orbits of the system is related to the geometry of the $p$-adic Siegel ... More

RELink: A Research Framework and Test Collection for Entity-Relationship RetrievalJun 13 2017Improvements of entity-relationship (E-R) search techniques have been hampered by a lack of test collections, particularly for complex queries involving multiple entities and relationships. In this paper we describe a method for generating E-R test queries ... More