Results for "Fernando Alarid-Escudero"

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Characterization and valuation of uncertainty of calibrated parameters in stochastic decision modelsJun 11 2019We evaluated the implications of different approaches to characterize uncertainty of calibrated parameters of stochastic decision models (DMs) in the quantified value of such uncertainty in decision making. We used a microsimulation DM of colorectal cancer ... More
Calculating the Expected Value of Sample Information in Practice: Considerations from Three Case StudiesMay 28 2019Investing efficiently in future research to improve policy decisions is an important goal. Expected Value of Sample Information (EVSI) can be used to select the specific design and sample size of a proposed study by assessing the benefit of a range of ... More
Neutrino decoupling beyond the Standard Model: CMB constraints on the Dark Matter mass with a fast and precise $N_{\rm eff}$ evaluationDec 13 2018Feb 08 2019The number of effective relativistic neutrino species represents a fundamental probe of the thermal history of the early Universe, and as such of the Standard Model of Particle Physics. Traditional approaches to the neutrino decoupling are either very ... More
Degeneracies with the Q.Q interaction in a single j shellMay 10 2016May 29 2016Previously [1] it was shown that for a configuration of 2 protons and 2 neutrons in the g_{9/2}shell there is a certain degeneracy that occurs when the quadrupole-quadrupole interaction (Q.Q) is used to to obtain the wave functions.. We here show 3 other ... More
More on Odd-J Pairing in NucleiDec 29 2012Apr 12 2013We point out a simplicity that arises when we use an interaction in which only an energy with odd J is non-zero. The emphasis is on J=J_{\text{max}} and in particular J=9^{+} in the g_{9/2} shell. It is noted that high overlaps can be deceptive. In many ... More
How degeneracies can obscure interesting physicsNov 16 2012We show how degeneracies, accidental or otherwise, can obscure some interesting physics. We further show how one can get around this problem.
Single j-shell studies of cross-conjugate nuclei and isomerismDec 20 2011May 09 2012It is noted that in a calculation with 4 nucleons with isospin 1 in a single j shell (f_{7/2}, g_{9/2}, h_{11/2}) the state with median angular momentum J = (J_{max}+1)/2 lies very low in energy becoming either an isomeric state or a ground state. Also ... More
Topics in Nuclear StructureJun 06 2013We consider work performed over the last decade on single-j-shell studies. We will discuss four topics.
The (2j-1) rule with other interactionsMay 11 2012Jun 24 2012We recently formulated a rule for isomeric states for a system of 4 nucleons with isospin T=1, namely that if the nucleons are in a single j shell then states with angular momenta J=2 and J=(2j-1) are either isomeric or ground states [ze12]. To show that ... More
Seniority conservation and seniority violation in the g_{9/2} shellNov 07 2005Dec 01 2005The g_{9/2} shell of identical particles is the first one for which one can have seniority-mixing effects. We consider three interactions: a delta interaction that conserves seniority, a quadrupole-quadrupole (QQ) interaction that does not, and a third ... More
Itô vs Stratonovich in the presence of absorbing statesNov 16 2018It is widely assumed that there exists a simple transformation from the It\^o interpretation to the Stratonovich one and back for any stochastic differential equation of applied interest. While this transformation exists under suitable conditions, and ... More
Superconducting properties of FeSe0.5Te0.5 under high pressureJan 07 2016This work reports studies performed in the superconducting compound FeSe0:5Te0:5 under high pressure. Changes were observed in the transition temperature, superconducting critical fields,anomalous variations in the Meissner fraction, and in Ginzburg Landau ... More
A construction of algebraic surfaces with many real nodesJul 18 2011Nov 07 2011A family of algebraic surfaces with many nondegenerate real singularities is introduced with the help of a construction, which has been used in previous works for the generation of substitution tilings.
Lepton masses and mixings in orbifold models with three Higgs familiesOct 19 2007Nov 05 2007We analyse the phenomenological viability of heterotic Z(3) orbifolds with two Wilson lines, which naturally predict three supersymmetric families of matter and Higgs fields. Given that these models can accommodate realistic scenarios for the quark sector ... More
Complex tensor factorisation with PARAFAC2 for the estimation of brain connectivity from the EEGMay 02 2017Objective: The coupling between neuronal populations and its magnitude have been shown to be informative for various clinical applications. One method to estimate brain connectivity is with electroencephalography (EEG) from which the cross-spectrum between ... More
Baryogenesis and Dark Matter from $B$ MesonsOct 01 2018Feb 21 2019We present a new mechanism of Baryogenesis and dark matter production in which both the dark matter relic abundance and the baryon asymmetry arise from neutral $B$ meson oscillations and subsequent decays. This set-up is testable at hadron colliders and ... More
P-V criticality in AdS black holes of massive gravityNov 16 2016In this paper we have studied the extended phase space thermodynamics in the canonical ensemble of black holes in massive gravity in AdS space. The black holes considered here belong to a theory of massive gravity where the graviton gain a mass due to ... More
An introduction to quantum plasmasJun 05 2012Shielding effects in non-degenerate and degenerate plasmas are compared. A detailed derivation of the Wigner-Poisson system is provided for electrostatic quantum plasmas where relativistic, spin and collisional effects are not essential. Later a detailed ... More
L-Borderenergetic graphsMay 14 2016The energy of a graph is defined as the sum the absolute values of the eigenvalues of its adjacency matrix. A graph G on n vertices is said to be borderenergetic if its energy equals the energy of the complete graph Kn. In this paper, we promote this ... More
Gaugino Condensation, Duality and Supersymmetry BreakingNov 17 1995The status of gaugino condensation in low-energy string theory is reviewed. Emphasis is given to the determination of the efective action below condensation scale in terms of the 2PI and Wilson actions. We illustrate how the different perturbative duality ... More
Noncompact Coset Spaces in String TheoryApr 03 1992A brief overview of strings propagating on noncompact coset spaces G/H is presented in terms of WZW models. The role played by isometries in the existence of target space duality and by fixed points of the gauge transformations in the existence of singularities ... More
Searches for Young PulsarsMay 19 2004I review the results of radio and X-ray searches for pulsations from young neutron stars, emphasizing work accomplished in the last five years. I cover undirected searches, as well as directed searches of pulsar wind nebulae, EGRET gamma-ray sources, ... More
Deep Searches for Young PulsarsOct 29 2002By 2000 there were only 10 established Galactic pulsar-supernova remnant associations. Two years later there are 16 such associations known. I discuss the work leading to this substantial increase. In particular I summarize an ongoing search project that ... More
A criterion for positive polynomialsDec 26 2003Jul 28 2004Let F be a homogeneous real polynomial of even degree in any number of variables. We consider the problem of giving explicit conditions on the coefficients so that F is positive definite or positive semi-definite. In this note we produce a necessary condition ... More
Towards the Self-constructive Brain: emergence of adaptive behaviorAug 07 2016Adaptive behavior is mainly the result of adaptive brains. We go a step beyond and claim that the brain does not only adapt to its surrounding reality but rather, it builds itself up to constructs its own reality. That is, rather than just trying to passively ... More
The approach of St"ohr-Voloch to the Hasse-Weil bound with applications to optimal curves and plane arcsNov 14 2000This is an expository paper concerning topics on rational points of curves defined over finite fields based on a paper by St"ohr and Voloch.
On the constellations of Weierstrass pointsApr 04 1996We prove that the constellation of Weierstrass points characterizes the isomorphism-class of double covering of curves of genus large enough.
Equivalence and normal forms of bilinear formsNov 04 2013Nov 19 2013We present an alternative account of the problem of classifying and finding normal forms for arbitrary bilinear forms. Beginning from basic results developed by Riehm, our solution to this problem hinges on the classification of indecomposable forms and ... More
Varieties of complexes and foliationsNov 23 2011Let $\mathcal F(r, d)$ denote the moduli space of algebraic foliations of codimension one and degree $d$ in complex proyective space of dimension $r$. We show that $\mathcal F(r, d)$ may be represented as a certain linear section of a variety of complexes. ... More
Homotopy theory of non-symmetric operads II: change of base category and left propernessApr 24 2013Aug 09 2013We prove, under mild assumptions, that a Quillen equivalence between symmetric monoidal model categories gives rise to a Quillen equivalence between their model categories of (non-symmetric) operads, and also between model categories of algebras over ... More
Dwyer-Kan homotopy theory of enriched categoriesJan 07 2012Mar 10 2014We construct a model structure on the category of small categories enriched over a combinatorial closed symmetric monoidal model category satisfying the monoid axiom. Weak equivalences are Dwyer-Kan equivalences, i.e. enriched functors which induce weak ... More
Reversed Dickson polynomials of the (k+1)-th kind over finite fieldsMay 13 2016We discuss the properties and the permutation behaviour of the reversed Dickson polynomials of the $(k+1)$-th kind $D_{n,k}(1,x)$ over finite fields. The results in this paper unify and generalize several recently discovered results on reversed Dickson ... More
Metamagnetism and Weak Ferromagnetism in Nickel (II) oxalate crystalsApr 12 2012Microcrystals of orthorhombic nickel (II) oxalate dihydrate were synthesized through a precipitation reaction of aqueous solutions of nickel chloride and oxalic acid. Magnetic susceptibility exhibits a sharp peak at 3.3 K and a broadrounded maximum near ... More
Weak ferromagnetism in cobalt oxalate crystalsDec 28 2010Microcrystals of diaquocobalt(II) oxalate have been synthesized by the coprecipitation reaction of aqueous solutions of Cobalt (II) bromide and oxalic acid. Chemical analysis and thermal experiments revealed that there is only one phase present. X-ray ... More
The number of J=0 pairs in {44,46,48}TiJan 25 2005In the single j-shell, the configuration of an even-even Ti isotope consists of 2 protons and n neutrons. The I=0 wave function can be written in terms of D(J,Jv)'s, which are the probability amplitudes for the 2 protons to couple to J and the n neutrons ... More
Gradings on classical central simple real Lie algebrasJul 25 2017For any abelian group $G$, we classify up to isomorphism all $G$-gradings on the classical central simple Lie algebras, except those of type $D_4$, over the field of real numbers (or any real closed field).
The Dispirited Case of Gauged $U(1)_{B-L}$ Dark MatterJun 07 2018Sep 18 2018We explore the constraints and phenomenology of possibly the simplest scenario that could account at the same time for the active neutrino masses and the dark matter in the Universe within a gauged $U(1)_{B-L}$ symmetry, namely right-handed neutrino dark ... More
FCNCs in supersymmetric multi-Higgs doublet modelsDec 02 2005Jul 27 2006We conduct a general discussion of supersymmetric models with three families in the Higgs sector. We analyse the scalar potential, and investigate the minima conditions, deriving the mass matrices for the scalar, pseudoscalar and charged states. Depending ... More
Nash multiplicities and resolution invariantsOct 30 2015Dec 20 2016The Nash multiplicity sequence was defined by M. Lejeune-Jalabert as a non-increasing sequence of integers attached to a germ of a curve inside a germ of a hypersurface. M. Hickel generalized this notion and described a sequence of blow ups which allows ... More
Low Momentum Classical Mechanics with Effective Quantum PotentialsMar 02 2005A recently introduced effective quantum potential theory is studied in a low momentum region of phase space. This low momentum approximation is used to show that the new effective quantum potential induces a space-dependent mass and a smoothed potential ... More
Uncertainty, incompleteness, chance, and designJan 29 2013Apr 09 2013The 20th century has revealed two important limitations of scientific knowledge. On the one hand, the combination of Poincar\'e's nonlinear dynamics and Heisenberg's uncertainty principle leads to a world picture where physical reality is, in many respects, ... More
String black hole: Can it be a particle accelerator ?Nov 06 2013Aug 21 2014In this paper we have studied the possibility of the center-of-mass energy of two particles colliding near the horizon of a static charged black hole in string theory. Various cases corresponding to the electric charge and the angular momentum of the ... More
Clifford theory for infinite dimensional modulesApr 28 2015Dec 29 2015Clifford theory of possibly infinite dimensional modules is studied
Normal modes, and acoustic properties, of an elastic solid with line defectsSep 23 2014The normal modes of a continuum solid endowed with a random distribution of line defects that behave like elastic strings are described. These strings interact with elastic waves in the bulk, generating wave dispersion and attenuation. As in amorphous ... More
Coherent-State Overcompleteness, Path Integrals, and Weak ValuesMar 12 2014Feb 18 2016In the Hilbert space of a quantum particle the standard coherent-state resolution of unity is written in terms of a phase-space integration of the outer product $|z\rangle \langle z|$. Because no pair of coherent states is orthogonal, one can represent ... More
Regular black holes in de Sitter universe: scalar field perturbations and quasinormal modesAug 14 2015The purpose of this paper is to study quasinormal modes (QNM) of a regular black hole with a cosmological constant due to scalar perturbations. A detailed study of the QNM frequencies for the massless scalar field were done by varying the parameters of ... More
Irreducible representations of unipotent subgroups of symplectic and unitary groups defined over ringsJul 27 2015Nov 01 2016Let $A$ be a ring with $1\neq 0$, not necessarily finite, endowed with an involution~$*$, that is, an anti-automorphism of order $\leq 2$. Let $H_n(A)$ be the additive group of all $n\times n$ hermitian matrices over $A$ relative to $*$. Let ${\mathcal ... More
Local String Models and Moduli StabilisationApr 21 2014Apr 29 2014A brief overview is presented of the progress made during the past few years on the general structure of local models of particle physics from string theory including: moduli stabilisation, supersymmetry breaking, global embedding in compact Calabi-Yau ... More
The Hyperradical and The Hopkins-Levitzki Theorem for Modular LatticesSep 07 2004Many arguments in the Theory of Rings and Modules are, on close inspection, purely Lattice theoretic arguments. Calagareanu} has a long repertoire of such results in his book. The Hopkins-Levitzki Theorem is interesting from this point of view, because ... More
Web 2.0 Technologies and Social Networking Security Fears in EnterprisesApr 09 2012Web 2.0 systems have drawn the attention of corporation, many of which now seek to adopt Web 2.0 technologies and transfer its benefits to their organizations. However, with the number of different social networking platforms appearing, privacy and security ... More
Determinant of complexes and higher HessiansJan 02 1996Let $X \subset \Bbb P^r$ be a smooth algebraic curve in projective space, over an algebraically closed field of characteristic zero. For each $m \in \Bbb N$, the $m$-flexes of $X$ are defined as the points where the osculating hypersurface of degree $m$ ... More
Massless relativistic wave equations and quantum field theoryMar 12 2003Dec 16 2003We give a simple and direct construction of a massless quantum field with arbitrary discrete helicity that satisfies Wightman axioms and the corresponding relativistic wave equation in the distributional sense. We underline the mathematical differences ... More
Maltsiniotis's first conjecture for K_1Jul 12 2007Oct 19 2007We show that K_1 of an exact category agrees with K_1 of the associated triangulated derivator. More generally we show that K_1 of a Waldhausen category with cylinders and a saturated class of weak equivalences coincides with K_1 of the associated right ... More
A note on the automorphism group of Schubert varietiesMay 12 2016Jan 08 2017In this work we extend some previously known results on the automorphism group of Schubert varieties. We consider the Schubert conditions which define a Schubert variety. An automorphism of the Grassmannian fixes a Schubert variety contained in it if ... More
On The 5D Extra-Force according to Basini-Capozziello-Ponce De Leon Formalism and the Experimental Research of Extra Dimensions On-Board International Space Station(ISS) using Laser BeamsOct 04 2007May 30 2013We analyze the possibility of Experimental Research of Extra Dimensions On-Board International Space Station (ISS) by using a Satellite carrying a Laser device(optical Laser) on the other side of Earth Orbit targeted towards ISS.The Sun will be between ... More
Self-Reciprocal Polynomials and Coterm PolynomialsJun 24 2016We classify all self-reciprocal polynomials arising from reversed Dickson polynomials over $\mathbb{Z}$ and $\mathbb{F}_p$, where $p$ is prime. As a consequence, we also obtain coterm polynomials arising from reversed Dickson polynomials.
Homotopy units in A-infinity algebrasNov 11 2011Apr 30 2014We show that the canonical map from the associative operad to the unital associative operad is a homotopy epimorphism for a wide class of symmetric monoidal model categories. As a consequence, the space of unital associative algebra structures on a given ... More
On the functoriality of cohomology of categoriesNov 22 2004In this paper we show that the Baues-Wirsching complex used to define cohomology of categories is a 2-functor from a certain 2-category of natural systems of abelian groups to the 2-category of chain complexes, chain homomorphism and relative homotopy ... More
Common ancestor type distribution: a Moran model and its deterministic limitAug 25 2015We study the common ancestor type distribution in a $2$-type Moran model with population size $N$, mutation and selection, and in the deterministic limit regime arising in the former when $N$ tends to infinity, without any rescaling of parameters or time. ... More
New Parametrizations for the Photon Structure FunctionJan 07 2006In the last year four new parametrizations of the Hadronic Photon Structure Function at Next to Leading Order have appeared. In this talk, I briefly review the main features of three of them: the FFNS_CJK, CJK and AFG.
Geometric properties of RM vector fields along curves in Riemannian manifoldsSep 27 2016Rotation minimizing vector fields and frames were introduced by Bishop as an alternative to the Frenet frame. They are used in CAGD because they can be defined even the curvature vanishes. Nevertheless, many other geometric properties have not been studied. ... More
Casimir effect around disclinationsMay 05 1995This communication concerns the structure of the electromagnetic quantum vacuum in a disclinated insulator. It is shown that a nonzero vacuum energy density appears when the rotational symmetry of a continuous insulating elastic medium is broken by a ... More
Enhancement of the magnetic moment of the electron due to a topological defectMay 23 1995In the framework of the theory of defects/three-dimensional gravitation, it is obtained a positive correction to the magnetic moment of the electron bound to a disclination in a dielectric solid.
Design for a Darwinian Brain: Part 1. Philosophy and NeuroscienceMar 28 2013Physical symbol systems are needed for open-ended cognition. A good way to understand physical symbol systems is by comparison of thought to chemistry. Both have systematicity, productivity and compositionality. The state of the art in cognitive architectures ... More
Non-Euclidean visibility problemsJul 27 2006We consider the analog of visibility problems in hyperbolic plane (represented by Poincar\'{e} half-plane model H), replacing the standard lattice $Z\times Z$ by the orbit $z=i$ under the full modular group $z$. We prove a visibility criterion and study ... More
Bounding the order of automorphisms of certain curvesNov 28 1994Aug 19 1995We study upper bounds on the order of automorphisms of non-singular curves $X$ satisfying at least one of the following hypothesis: 1) $X$ is an $m$-sheeted covering of exactly one non-singular curve of genus $\gamma$, where $m$ is prime; 2) the center ... More
Conformal covariance of massless free netsJun 16 2000In the present paper we review in a fibre bundle context the covariant and massless canonical representations of the Poincare' group as well as certain unitary representations of the conformal group (in 4 dimensions). We give a simplified proof of the ... More
A triangulated category without modelsMar 11 2007We exhibit a triangulated category which is neither the stable category of a Frobenius category nor a full triangulated subcategory of the homotopy category of a stable model category.
Modular Theory by exampleJan 08 2009The present article contains a short introduction to Modular Theory for von Neumann algebras with a cyclic and separating vector. It includes the formulation of the central result in this area, the Tomita-Takesaki theorem, and several of its consequences. ... More
More on Equienergetic Threshold GraphsJul 02 2018The energy of a graph is defined as the sum the absolute values of the eigenvalues of its adjacency matrix. A threshold graph G on n vertices is coded by a binary sequence of length n. In this paper we answer a question posed by Jacobs et al. [Eigenvalues ... More
Explicit solutions of Jensen's auxiliary equations via extremal Lipschitz extensionsJul 22 2019In this note we prove that McShane and Whitney's Lipschitz extensions are viscosity solutions of Jensen's auxiliary equations, known to have a key role in Jensen's celebrated proof of uniqueness of infinity harmonic functions, and therefore of Absolutely ... More
Conjugacy classes of p-cycles of type D in alternating groupsNov 27 2012Mar 04 2014We classify the conjugacy classes of p-cycles of type D in alternating groups. This finishes the open cases in arXiv:0812.4628. We also determine all the subracks of those conjugacy classes which are not of type D.
Cylinders for non-symmetric DG-operads via homological perturbation theoryMay 12 2015We construct small cylinders for cellular non-symmetric DG-operads over an arbitrary commutative ring by using the basic perturbation lemma from homological algebra. We show that our construction, applied to the A-infinity operad, yields the operad parametrizing ... More
Enhanced $A$-infinity obstruction theoryOct 01 2015Mar 12 2018We extend the Bousfield-Kan spectral sequence for the computation of the homotopy groups of the space of minimal A-infinity algebra structures on a graded projective module. We use the new part to define obstructions to the extension of truncated minimal ... More
A Note on Permutation Binomials and Trinomials over Finite FieldsSep 22 2016Feb 05 2017Let $p$ be an odd prime and $e$ be a positive integer. We completely explain the permutation binomials and trinomials arising from the reversed Dickson polynomials of the $(k+1)$-th kind $D_{n,k}(1,x)$ over $\mathbb{F}_{p^e}$ when $n=p^l+2$, where $l\in ... More
Elastic forces that do no work and the dynamics of fast cracksJul 17 1995Jul 18 1995Elastic singularities such as crack tips, when in motion through a medium that is itself vibrating, are subject to forces orthogonal to the direction of motion and thus impossible to determine by energy considerations alone. This fact is used to propose ... More
Quantum Weibel InstabilityNov 06 2007The Weibel instability is analyzed for quantum plasmas described by the Wigner-Maxwell model. For a suitable class of electromagnetic potentials, the Wigner-Maxwell system is linearized yielding a general dispersion relation for transverse electromagnetic ... More
Josephson effect between Bose condensatesOct 26 1998I present an overview of the physics of the Josephson effect between Bose condensed systems, with emphasis on the recently achieved BEC's in trapped alkali gases. I focus mostly on those physical phenomena that are likely to be observed only (or more ... More
On the scaling property in fluctuation theory for stable Lévy processesJul 22 2010We find an expression for the joint Laplace transform of the law of $(T_{[x,+\infty[},X_{T_{[x,+\infty[}})$ for a L\'evy process $X$, where $T_{[x,+\infty[}$ is the first hitting time of $[x,+\infty[$ by $X$. When $X$ is an $\alpha$-stable L\'evy process, ... More
Pseudo-Query ReformulationJul 14 2015Automatic query reformulation refers to rewriting a user's original query in order to improve the ranking of retrieval results compared to the original query. We present a general framework for automatic query reformulation based on discrete optimization. ... More
Born-Infeld-de Sitter gravity: Cold, ultracold and Nariai black holesDec 30 2013Aug 16 2014In this paper, we have presented interesting properties of the static charged Born-Infeld-de Sitter black hole. They can have time-like as well as space-like singularities depending on the parameters of the theory. The degenerate black holes lead to cold, ... More
Quasinormal modes of dilaton-de Sitter black holes: scalar perturbationsJan 24 2016Dilaton black hole solutions in low energy string theory (well known as GMGHS black holes) have analogue black holes with a cosmological constant derived by Gao and Zhang. Here, we study quasi normal modes of this dilaton-de Sitter black hole under neutral ... More
Hamilton-Dirac systems for charged particles in gauge fieldsOct 13 2014Apr 07 2015In this work, we use the Sternberg phase space (which may be considered as the classical phase space of particles in gauge fields) in order to explore the dynamics of such particles in the context of Hamilton-Dirac systems and their associated Hamilton-Pontryagin ... More
Superstring Phenomenology: An OverviewJul 22 1997The different aspects of superstring phenomenology before and after 1995 are briefly reviewed. (Contribution to the conference SUSY97)
Duality and Global SymmetriesJun 27 1997This is a general introduction to duality in field theories. The existence and breaking of global symmetries is used as a guideline to systematically prove duality between different field theories. Systems discussed include abelian and non-abelian T-duality ... More
Hyperbolic classification of natural numbers and Goldbach ConjectureJul 17 2005Jun 22 2007By means of a dynamical process we provide a characterization of the Goldbach Conjecture in an infinite set of even numbers that depends on time.
The Deligne-Lusztig curve associated to the Suzuki groupJun 26 1997We give a characterization of the Deligne-Lusztig curve associated to the Suzuki group based on the genus and the number of rational points of the curve.
Some Graded Identities of The Cayley-Dickson AlgebraMay 22 2012We work to find a basis of graded identities for the octonion algebra. We do so for the $\mathbb{Z}_2^2$ and $\mathbb{Z}_2^3$ gradings, both of them derived of the Cayley-Dickson process, the later grading being possible only when the characteristic of ... More
On spectral approximation, Følner sequences and crossed productsAug 06 2010Oct 09 2012In this article we study Foelner sequences for operators and mention their relation to spectral approximation problems. We construct a canonical Foelner sequence for the crossed product of a discrete amenable group $\Gamma$ with a concrete C*-algebra ... More
Equivalence and congruence of matrices under the action of standard parabolic subgroupsAug 21 2013We find necessary and sufficient conditions for $P$-equivalence of arbitrary matrices and $P$-congruence of symmetric and alternating matrices, where $P$ is standard parabolic subgroup of $GL_n(F)$ and $F$ is an arbitrary field.
The first passage time of a stable process conditioned to not overshootNov 15 2012Jan 07 2015Consider a stable L\'evy process $X=(X_t,t\geq 0)$ and let $T_x$, for $x>0$, denote the first passage time of $X$ above the level $x$. In this work, we give an alternative proof of the absolute continuity of the law of $T_x$ and we obtain a new expression ... More
Sufficient conditions for the convergence of the Magnus expansionNov 15 2007Two different sufficient conditions are given for the convergence of the Magnus expansion arising in the study of the linear differential equation $Y' = A(t) Y$. The first one provides a bound on the convergence domain based on the norm of the operator ... More
Homotopy theory of non-symmetric operadsJan 09 2011We endow categories of non-symmetric operads with natural model structures. We work with no restriction on our operads and only assume the usual hypotheses for model categories with a symmetric monoidal structure. We also study categories of algebras ... More
On the unit of a monoidal model categoryNov 05 2014Nov 13 2014In this paper we show how to modify cofibrations in a monoidal model category so that the tensor unit becomes cofibrant while keeping the same weak equivalences. We obtain aplications to enriched categories and coloured operads in stable homotopy theory. ... More
Reversed Dickson Polynomials of the Third KindFeb 15 2016Aug 08 2016Let $p$ be a prime and $q=p^e$. We discuss the properties of the reversed Dickson polynomial $D_{n,2}(1,x)$ of the third kind. We also give several necessary conditions for the reversed Dickson polynomial of the third kind $D_{n,2}(1,x)$ to be a permutation ... More
Singular 2 webs and Polar CurvesApr 21 2013A 2-web in the plane is given by two everywhere transverse 1-foliations. In this paper we introduce the study of singular 2-webs, given by any two foliations, which may be tangent in some points. We show that such two foliations are tangent along a curve, ... More
Enveloping actions and Takai duality for partial actionsJul 17 2000We show that any continuous partial action on a topological space has a unique enveloping action, i.e. it is the restriction of a global action. In the case of C^*-algebras we prove that any partial action has an enveloping action up to Morita equivalence. ... More
Quantum MagnetohydrodynamicsMar 02 2005The quantum hydrodynamic model for charged particle systems is extended to the cases of non zero magnetic fields. In this way, quantum corrections to magnetohydrodynamics are obtained starting from the quantum hydrodynamical model with magnetic fields. ... More
On the relevance of quantum models for plasmasOct 01 2012Recently there has been a claim on the complete irrelevance of quantum modeling for plasmas. We address this subject from basic principles. Physical situations where quantum effects play a decisive role are identified.
The damped Pinney equation and its applications to dissipative quantum mechanicsDec 25 2007Dec 18 2009The work considers the damped Pinney equation, defined as the model arising when a linear in velocity damping term is included in the Pinney equation. In the general case the resulting equation does not admit Lie point symmetries or is reducible to a ... More