Results for "Andrés Aranda"

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Morphism extension classes of countable $L$-colored graphsMay 04 2018In~\cite{Hartman:2014}, Hartman, Hubi\v cka and Ma\v sulovi\'c studied the hierarchy of morphism extension classes for finite $L$-colored graphs, that is, undirected graphs without loops where sets of colors selected from $L$ are assigned to vertices ... More
The independence number of HH-homogeneous graphs and a classification of MB-homogeneous graphsFeb 08 2019We show that the independence number of a countably infinite HH-homogeneous graph that does not contain the Rado graph as a spanning subgraph is finite and present a classification of MB-homogeneous graphs up to bimorphism-equivalence as a consequence. ... More
Thin Position for 4-manifoldsMay 22 2018Jan 17 2019Motivated by M. Scharlemann and A. Thompson's definition of thin position of 3-manifolds, we define the width of a Kirby diagram and introduce the notion of thin position of a compact smooth $4-$manifold with connected boundary. We determine all manifolds ... More
Neutrino mixing from the double tetrahedral group T^{\prime}Jul 25 2007Nov 09 2007It is shown that it is possible to create successful models of flavor for both quarks and leptons using the discrete non-abelian group $T^{\prime}$ by itself. Two simple realizations are presented that can be used as the starting point for more general ... More
Electroweak scale neutrinos and HiggsesDec 16 2008We present two different models with electroweak scale right-handed neutrinos. One of the models is created under the constraint that any addition to the Standard Model must not introduce new higher scales. The model contains right-handed neutrinos with ... More
Models of Flavor with Discrete SymmetriesNov 20 2002In an attempt to understand the observed patterns of lepton and quark masses, models invoking a flavor symmetry $G_f$, under which the Standard Model generations are charged, have been proposed. One particularly successful symmetry, U(2), has been extensively ... More
Minimal genus four manifoldsJan 28 2019In 2018, M. Chu and S. Tillmann gave a lower bound for the trisection genus of a closed 4-manifold in terms of the Euler characteristic of $M$ and the rank of its fundamental group. We show that given a group $G$, there exist a 4-manifold $M$ with fundamental ... More
Fine gradings on simple exceptional Jordan pairs and triple systemsAug 21 2015We give a classification up to equivalence of the fine group gradings by abelian groups on the Jordan pairs and triple systems of types bi-Cayley and Albert, under the assumption that the base field is algebraically closed of characteristic different ... More
A new radiative neutrino mass generation mechanism with higher dimensional scalar representations and custodial symmetryAug 05 2015Jan 06 2016A new realization for radiative neutrino mass generation is presented. Based on the requirement of tree-level custodial symmetry and the introduction of higher (greater than two) dimensional representations for scalar fields, a specific scenario with ... More
Standard Model Extension with Flipped GenerationsJul 04 2018Oct 30 2018An extension of the Standard Model is presented that leads to the possible existence of new gauge bosons with masses in the range of a few TeV. Due to the fact that their couplings to Standard Model fermions are strongly suppressed, it is possible for ... More
Generations of Higgs Bosons in Supersymmetric ModelsMay 11 2000Jul 26 2000We examine extensions of the MSSM with more than one generation of Higgs bosons. If one assumes that a symmetry eliminates the tree-level FCNC, then the extra scalar bosons do not acquire VEVs, do not couple to fermions and do not mix with the ordinary ... More
Gradings on composition superalgebrasDec 04 2013Feb 04 2014We classify up to equivalence the gradings on Hurwitz superalgebras and on symmetric composition superalgebras, over any field. Also, classifications up to isomorphism are given in case the field is algebraically closed. By grading, here we mean group ... More
Improved Lindstedt-Poincare method for the solution of nonlinear problemsMar 23 2003We apply the Linear Delta Expansion (LDE) to the Lindstedt-Poincare (``distorted time'') method to find improved approximate solutions to nonlinear problems. We find that our method works very well for a wide range of parameters in the case of the anharmonic ... More
brTPF: Bindings-Restricted Triple Pattern Fragments (Extended Preprint)Aug 29 2016Aug 30 2016The Triple Pattern Fragment (TPF) interface is a recent proposal for reducing server load in Web-based approaches to execute SPARQL queries over public RDF datasets. The price for less overloaded servers is a higher client-side load and a substantial ... More
Orthogonal U(1)'s, Proton Stability and Extra DimensionsDec 07 2000Jan 19 2001In models with a low quantum gravity scale, one might expect that all operators consistent with gauge symmetries are present in the low-energy effective theory. If this is the case, some mechanism must be present to adequately suppress operators that ... More
Limits on a Light Leptophobic Gauge BosonSep 24 1998We consider the phenomenology of a naturally leptophobic $Z$-prime boson in the 1 to 10 GeV mass range. The $Z$-prime's couplings to leptons arise only via a radiatively-generated kinetic mixing with the $Z$ and photon, and hence are suppressed. We map ... More
Quantitative properties of convex representationsApr 25 2011Jan 28 2012Let $\Gamma$ be a discrete subgroup of $\textrm{PGL}(d,\R)$ and fix some euclidean norm $\|\ \|$ on $\R^d.$ Let $N_\Gamma(t)$ be the number of elements in $\Gamma$ whose operator norm is $\leq t.$ In this article we prove an asymptotic for the growth ... More
Cohomological vertex operatorsJul 26 2016Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the ... More
Ga+, In+ and Tl+ Impurities in Alkali Halide Crystals: Distortion TrendsAug 30 2000A computational study of the doping of alkali halide crystals (AX: A = Na, K; X = Cl, Br) by ns2 cations (Ga+, In+ and Tl+) is presented. Active clusters of increasing size (from 33 to 177 ions) are considered in order to deal with the large scale distortions ... More
A characteristic number of bundles determined by mass linear pairsSep 09 2008Nov 13 2008Let $\Delta$ be a Delzant polytope in ${\mathbb R}^n$ and ${\bf b}\in{\mathbb Z}^n$. Let $E$ denote the symplectic fibration over $S^2$ determined by the pair $(\Delta, {\bf b})$. We prove the equivalence between the fact that $(\Delta, {\bf b})$ is a ... More
A Bhatnagar-Gross-Krook-like Model Kinetic Equation for a Granular Gas of Inelastic Rough Hard SpheresJul 05 2010May 25 2011The Boltzmann collision operator for a dilute granular gas of inelastic rough hard spheres is much more intricate than its counterpart for inelastic smooth spheres. Now the one-body distribution function depends not only on the translational velocity ... More
Non-Hamiltonian isotopic Lagrangians on the one-point blow-up of CP^2Feb 14 2017We show that two Hamiltonian isotopic Lagrangians in (CP^2,\omega_\textup{FS}) induce two Lagrangian submanifolds in the one-point blow-up (\widetilde{CP}^2,\widetilde{\omega}_\rho) that are not Hamiltonian isotopic. Furthermore, we show that for any ... More
Spanning Class in the Category of BranesApr 11 2018Given a generic anticanonical hypersurface $Y$ of a toric variety determined by a reflexive polytope, we define a line bundle ${\mathcal L}$ on $Y$ that generates a spanning class in the bounded derivative category $D^b(Y)$. From this fact, we deduce ... More
Equivariant branesFeb 06 2015Feb 10 2015Given a Calabi-Yau manifold $X$ acted by a group $G$ and considering the $B$-branes on $X$ as objects in the derived category of coherent sheaves, we give a definition of equivariant branes, which generalizes the concept of equivariant sheaves. We also ... More
An orbital-free molecular dynamics study of melting in K_20, K_55, K_92, K_142, Rb_55 and Cs_55 clustersMay 22 2000Feb 24 2001The melting-like transition in potasium clusters K_N, with N=20, 55, 92 and 142, is studied by using an orbital-free density-functional constant-energy molecular dynamics simulation method, and compared to previous theoretical results on the melting-like ... More
Melting behavior of large disordered sodium clustersMay 18 2000The melting-like transition in disordered sodium clusters Na_N, with N=92 and 142 is studied by using a first-principles constant-energy molecular dynamics simulation method. Na_142, whose atoms are distributed in two (surface and inner) main shells with ... More
Lagrangian Floer homology on symplectic blow upsApr 08 2019We show how to compute the Lagrangian Floer homology in the one-point blow up of the proper transform of Lagrangians submanifolds, solely in terms of information of the base manifold. As an example we present an alternative computation of the Lagrangian ... More
Living Without a Mobile Phone: An AutoethnographyApr 13 2018This paper presents an autoethnography of my experiences living without a mobile phone. What started as an experiment motivated by a personal need to reduce stress, has resulted in two voluntary mobile phone breaks spread over nine years (i.e., 2002-2008 ... More
A Quick View of Lagrangian Floer HomologyJan 09 2017In this note we present a brief introduction to Lagrangian Floer homology and its relation with the solution of Arnol'd conjecture, on the minimal number of non-degenerate fixed points of a Hamiltonian diffeomorphism. We start with the basic definition ... More
Action integrals and infinitesimal charactersAug 14 2008Oct 26 2009Let $G$ be a reductive Lie group and ${\mathcal O}$ the coadjoint orbit of a hyperbolic element of ${\frak g}^*$. By $\pi$ is denoted the unitary irreducible representation of $G$ associated with ${\mathcal O}$ by the orbit method. We give geometric interpretations ... More
Comments on "State equation for the three-dimensional system of 'collapsing' hard spheres"Sep 16 2009Nov 09 2009A recent paper [I. Klebanov et al. \emph{Mod. Phys. Lett. B} \textbf{22} (2008) 3153; arXiv:0712.0433] claims that the exact solution of the Percus-Yevick (PY) integral equation for a system of hard spheres plus a step potential is obtained. The aim of ... More
Characteristic number associated to mass linear pairsJun 15 2011Aug 09 2011Let $\Delta$ be a Delzant polytope in ${\mathbb R}^n$ and ${\mathbf b}\in{\mathbb Z}^n$. Let $E$ denote the symplectic fibration over $S^2$ determined by the pair $(\Delta,\,{\mathbf b})$. Under certain hypotheses, we prove the equivalence between the ... More
Hamiltonian diffeomorphisms of toric manifoldsJun 09 2005We prove that $\pi_1(\text{Ham}(M))$ contains an infinite cyclic subgroup, where $\text{Ham}(M)$ is the Hamiltonian group of the one point blow up of ${\Bbb C}P^3$. We give a sufficient condition for the group $\pi_1(\text{Ham}(M))$ to contain an infinite ... More
Critical values of moment maps on quantizable manifoldsNov 02 2007Let $M$ be a quantizable symplectic manifold acted on by $T=(S^1)^r$ in a Hamiltonian fashion and $J$ a moment map for this action. Suppose that the set $M^{T}$ of fixed points is discrete and denote by ${\alpha}_{pj}\in{\mathbb Z}^r$ the weights of the ... More
Cohomological vertex operatorsJul 26 2016Jan 12 2017Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the ... More
The amazing story of a forgotten golden flagOct 04 2015Oct 08 2015We describe the most probable geometric design of the Chilean Independence Flag, which uses the golden ratio in many of its components. We also discuss some related historical aspects.
A remarkable family of left ordered groups: central extensions of Hecke groupsSep 28 2009Oct 23 2010We provide an infinite family of left-ordered groups, all of which have a positive cone that is finitely generated as a semigroup. This family includes the Klein bottle group and the braid group B_3.
Growth of groups and diffeomorphisms of the intervalAug 18 2005Apr 08 2007We prove that the so called Grigorchuk-Maki group of intermadiate growth can be seen as a group of $C^1$ diffeomorphisms of the interval. On the other hand, we prove that every group of $C^{1+\alpha}$ diffeomorphisms of the interval having subexponential ... More
An example concerning the Theory of Levels for codimension-one foliationsSep 06 2008We give an example of a codimension-one foliation which is transversely of class C^1 and which does not satisfy the "Local Minimal Set" property.
Ramsey expansions of metrically homogeneous graphsJul 09 2017Dec 28 2017We discuss the Ramsey property, the existence of a stationary independence relation and the coherent extension property for partial isometries (coherent EPPA) for all classes of metrically homogeneous graphs from Cherlin's catalogue, which is conjectured ... More
TMI! How Knowledge Platforms Tame the Information Overload and Advance Global Development Through TechnologySep 28 2016Finding reliable data to inform decisions about technology for global development remains a challenge. Easily accessible "Knowledge platforms" are a way to curate and standardize information about technology for development. Three collaborators, Engineering ... More
When the C in CP does not matter: anatomy of CP-half-odd scalars and their Yukawa interactionsAug 31 2016Sep 24 2016We explore the origin and Yukawa interactions of the peculiar CP-half-odd scalars that were recently found in a multi-Higgs model based on an order-4 CP symmetry. We relate the existence of such scalars to the enhanced freedom of defining CP, even beyond ... More
Representativity and waist of cable knotsApr 27 2017We study the incompressible surfaces in the exterior of a cable knot and use this to compute the representativity and waist of most cable knots.
Playing with Marbles: Structural and Thermodynamic Properties of Hard-Sphere SystemsOct 21 2013These lecture notes present an overview of equilibrium statistical mechanics of classical fluids, with special applications to the structural and thermodynamic properties of systems made of particles interacting via the hard-sphere potential or closely ... More
Class of consistent fundamental-measure free energies for hard-sphere mixturesAug 15 2012Oct 05 2012In fundamental-measure theories the bulk excess free-energy density of a hard-sphere fluid mixture is assumed to depend on the partial number densities ${\rho_i}$ only through the four scaled-particle-theory variables ${\xi_\alpha}$, i.e., $\Phi({\rho_i})\to\Phi({\xi_\alpha})$. ... More
Comment on `A general integral identity'Sep 29 2011A simple heuristic proof of an integral identity recently derived (Glasser ML 2011 J. Phys. A: Math. Theor. 44 225202) is presented.
Homogeneous Free Cooling State in Binary Granular Fluids of Inelastic Rough Hard SpheresJul 05 2010May 26 2011In a recent paper [A. Santos, G. M. Kremer, and V. Garz\'o, \emph{Prog. Theor. Phys. Suppl.} \textbf{184}, 31-48 (2010)] the collisional energy production rates associated with the translational and rotational granular temperatures in a granular fluid ... More
Flat Affine and Symplectic Geometries on Lie GroupsOct 04 2017In this paper we exhibit a family of flat left invariant affine structures on the double Lie group of the oscillator Lie group of dimension 4, associated to each solution of classical Yang-Baxter equation given by Boucetta and Medina. On the other hand, ... More
Extreme values for $S_n(σ,t)$ near the critical lineJul 31 2018Let $S(\sigma,t)=\frac{1}{\pi}\arg\zeta(\sigma+it)$ be the argument of the Riemann zeta function at the point $\sigma+it$ of the critical strip. For $n\geq 1$ and $t>0$ we define $$ S_{n}(\sigma,t) = \int_0^t S_{n-1}(\sigma,\tau)\,d\tau\, + \delta_{n,\sigma\,}, ... More
Lifting Hamiltonian loops to isotopies in fibrationsFeb 22 2013Let $G$ be a Lie group, $H$ a closed subgroup and $M$ the homogeneous space $G/H$. Each representation $\Psi$ of $H$ determines a $G$-equivariant principal bundle ${\mathcal P}$ on $M$ endowed with a $G$-invariant connection. We consider subgroups ${\mathcal ... More
Sur les rapprochements par conjugaison en dimension 1 et classe C^1Aug 23 2012Nov 08 2013We prove that the space of actions of Z^d by C^1 (orientation-preserving) diffeomorphisms of either the interval or the circle is connected by arcs. This is proved by showing that all such actions can be C^0 conjugated via a 1-parameter family into diffeomorphisms ... More
Group actions on 1-manifolds: a list of very concrete open questionsDec 18 2017Apr 20 2018This text focuses on actions on 1-manifolds. We present a (non exhaustive) list of very concrete open questions in the field, each of which is discussed in some detail and complemented with a large list of references, so that a clear panorama on the subject ... More
Wandering domains for diffeomorphisms of the k-torus: a remark on a theorem by Norton and SullivanFeb 08 2017We show that there is no C^{k+1} diffeomorphism of the k-torus which is semiconjugate to a minimal translation and has a wandering domain all of whose iterates are Euclidean balls.
Self-energy renormalization around the flux phase in the $t-J$ model: Possible implications in underdoped cupratesFeb 14 2008The flux phase predicted by the $t-J$ model in the large-N limit exhibits features that make it a candidate for describing the pseudogap regime of cuprates. However certain properties, as for instance the prediction of well defined quasiparticle peaks, ... More
$t-J$ model one-electron renormalizations: high energy features in photoemission experiments of high-$T_c$ cupratesMar 06 2007Recent angle-resolved photoemission experiments in hole doped cuprates reported new and interesting high energy features which may be useful for understanding the electronic properties of these materials. Using a perturbative approach, which allows the ... More
Evidence for two competing order parameters in underdoped cuprates superconductors from a model analysis of the Fermi-arc effectsNov 10 2009Preformed pairs above $T_c$ and the two-gap scenarios are two main proposals for describing the low doping pseudogap phase of high-$T_c$ cuprates. Very recent angle-resolved photoemission experiments have shown features which were interpreted as evidence ... More
On entropy, regularity and rigidity for convex representations of hyperbolic manifoldsMar 27 2013Dec 18 2014Given a convex representation $\rho:\Gamma\to\textrm{PGL}(d,\mathbb{R})$ of a convex co-compact group $\Gamma$ of $\mathbb{H}^k$ we find upper bounds for the quantity $\alpha h_\rho,$ where $h_\rho$ is the entropy of $\rho$ and $\alpha$ is the H\"older ... More
Action Integrals and discrete seriesAug 08 2011Let $G$ be a complex semisimple Lie group and ${G}_{\mathbb R}$ a real form that contains a compact Cartan subgroup $T_{\mathbb R}$. Let $\pi$ be a discrete series representation of $G_{\mathbb R}$. We present geometric interpretations in terms of concepts ... More
Note: An exact scaling relation for truncatable free energies of polydisperse hard-sphere mixturesFeb 03 2012Apr 07 2012A theoretical model for polydisperse systems of hard spheres is said to be truncatable when the excess free energy depends on the size distribution through a finite number $K$ of moments. This Note proves an exact scaling relation for truncatable free ... More
Chemical-Potential Route: A Hidden Percus-Yevick Equation of State for Hard SpheresApr 20 2012Sep 21 2012The chemical potential of a hard-sphere fluid can be expressed in terms of the contact value of the radial distribution function of a solute particle with a diameter varying from zero to that of the solvent particles. Exploiting the explicit knowledge ... More
Solutions of the moment hierarchy in the kinetic theory of Maxwell modelsMar 05 2009Dec 05 2009In the Maxwell interaction model the collision rate is independent of the relative velocity of the colliding pair and, as a consequence, the collisional moments are bilinear combinations of velocity moments of the same or lower order. In general, however, ... More
A Characteristic Number of Hamiltonian Bundles over $S^2$Jun 09 2005Dec 16 2005Each loop $\psi$ in the group $\text{Ham}(M)$ of Hamiltonian diffeomorphisms of a symplectic manifold $M$ determines a fibration $E$ on $S^2$, whose coupling class \cite{G-L-S} is denoted by $c$. If $VTE$ is the vertical tangent bundle of $E$, we relate ... More
Continuous families of Hamiltonian torus actionsMay 19 2008We determine conditions under which two Hamiltonian torus actions on a symplectic manifold $M$ are homotopic by a family of Hamiltonian torus actions, when $M$ is a toric manifold and when $M$ is a coadjoint orbit.
A note on entire $L$-functionsMay 03 2018In this paper, we exhibit upper and lower bounds with explicit constants for some objects related to entire $L$-functions in the critical strip, under the generalized Riemann hypothesis. The examples include the entire Dirichlet $L$-functions $L(s,\chi)$ ... More
A finitely generated, locally indicable group with no faithful action by C^1 diffeomorphisms of the intervalFeb 26 2009According to Thurston's stability theorem, every group of C^1 diffeomorphisms of the closed interval is locally indicable (.e., every finitely generated subgroup factors through Z). We show that, even for finitely generated groups, the converse of this ... More
Groups, orders, and lawsMay 05 2014We discuss the question whether left-orderable groups satisfying a nontrivial law are locally indicable.
On centralizers of interval diffeomorphisms in critical (intermediate) regularitySep 05 2013We extend to the critical (intermediate) regularity several results concerning rigidity for centralizers and group actions on the interval.
On the dynamics of (left) orderable groupsOct 12 2007Feb 16 2010We study left orderable groups by using dynamical methods. We apply these techniques to study the space of orderings of these groups. We show for instance that for the case of (non-Abelian) free groups, this space is homeomorphic to the Cantor set. We ... More
Non-Hamiltonian isotopic Lagrangians on the one-point blow-up of CP^2Feb 14 2017Apr 11 2019We show that two Hamiltonian isotopic Lagrangians in (CP^2,\omega_\textup{FS}) induce two Lagrangian submanifolds in the one-point blow-up (\widetilde{CP}^2,\widetilde{\omega}_\rho) that are not Hamiltonian isotopic. Furthermore, we show that for any ... More
Charge of $D$-branes on singular varietiesNov 19 2018Considering the $D$-branes on a variety $Z$ as the objects of the derived category $D^b(Z)$, we propose a definition for the charge of $D$-branes on not necessarily smooth varieties. We define the charge $Q({\mathcal G})$ of ${\mathcal G}\in D^b(Z)$ as ... More
Weyl groups of the fine gradings on $\e_6$Aug 02 2013The Weyl groups of the fine gradings with infinite universal grading group on $\mathfrak{e}_6$ are given.
Completing graphs to metric spacesJun 01 2017Mar 04 2019We prove that certain classes of metrically homogeneous graphs omitting triangles of odd short perimeter as well as triangles of long perimeter have the extension property for partial automorphisms and we describe their Ramsey expansions.
Pion dispersion relation at finite density and temperatureJul 04 2002Oct 24 2002We study the behavior of the pion dispersion relation in a pion medium at finite density and temperature. We introduce a pion chemical potential to describe the finite pion number density and argue that such description is valid during the hadronic phase ... More
Completing graphs to metric spacesJun 01 2017Jun 25 2017We prove that certain classes of metrically homogeneous graphs omitting triangles of odd short perimeter as well as triangles of long perimeter have the extension property for partial automorphisms and we describe their Ramsey expansions.
The Brown-York mass of black holes in Warped Anti-de Sitter spaceDec 10 2012Feb 25 2013We give a direct computation of the mass of black holes in Warped Anti-de Sitter space (WAdS) in terms of the Brown-York stress-tensor at the boundary. This permits to explore to what extent the holographic renormalization techniques can be applied to ... More
Identification of a new relatively old star cluster in the Small Magellanic CloudJul 31 2012We present results on the age and metallicity estimates of the astonishingly unstudied SMC cluster ESO 51-SC09, from CCD BVI photometry obtained at the ESO NTT with the EMMI attached. ESO 51-SC09 turns out to be a relatively small cluster (FWHM = (10 ... More
Minimal data at a given point of space for solutions to certain geometric systemsJan 13 2010We consider a geometrical system of equations for a three dimensional Riemannian manifold. This system of equations has been constructed as to include several physically interesting systems of equations, such as the stationary Einstein vacuum field equations ... More
Time-Symmetric Cellular AutomataDec 03 2010Together with the concept of reversibility, another relevant physical notion is time-symmetry, which expresses that there is no way of distinguishing between backward and forward time directions. This notion, found in physical theories, has been neglected ... More
Multicomponent fluid of nonadditive hard spheres near a wallFeb 03 2013Apr 05 2013A recently proposed rational-function approximation [Phys. Rev. E \textbf{84}, 041201 (2011)] for the structural properties of nonadditive hard spheres is applied to evaluate analytically (in Laplace space) the local density profiles of multicomponent ... More
Limit Models in Metric Abstract Elementary Classes: the Categorical caseApr 25 2013Apr 13 2015We study versions of limit models adapted to the context of *metric abstract elementary classes*. Under categoricity and superstability-like assumptions, we generalize some theorems from [GrVaVi]. We prove criteria for existence and uniqueness of limit ... More
Non-Newtonian Couette-Poiseuille flow of a dilute gasSep 15 2010Jan 20 2011The steady state of a dilute gas enclosed between two infinite parallel plates in relative motion and under the action of a uniform body force parallel to the plates is considered. The Bhatnagar-Gross-Krook model kinetic equation is analytically solved ... More
Multipoint flux mixed finite element methods for slightly compressible flow in porous mediaNov 06 2018In this paper, we consider multipoint flux mixed finite element discretizations for slightly compressible Darcy flow in porous media. The methods are formulated on general meshes composed of triangles, quadrilaterals, tetrahedra or hexahedra. An inexact ... More
Velocity Distribution and Cumulants in the Unsteady Uniform Longitudinal Flow of a Granular GasJul 06 2012Nov 30 2012The uniform longitudinal flow is characterized by a linear longitudinal velocity field $u_x(x,t)=a(t)x$, where $a(t)={a_0}/({1+a_0t})$ is the strain rate, a uniform density $n(t)\propto a(t)$, and a uniform granular temperature $T(t)$. Direct simulation ... More
The star cluster frequency throughout the Large Magellanic CloudOct 16 2013We address the issue about the variation of the star cluster frequency (CF) in the Large Magellanic Cloud (LMC) in terms of the cluster spatial distribution. We adopted the LMC regions traced by Harris & Zaritsky (2009) and used an updated version of ... More
Toward categoricity for classes with no maximal modelsJul 15 1997We provide here the first steps toward Classification Theory of Abstract Elementary Classes with no maximal models, plus some mild set theoretical assumptions, when the class is categorical in some lambda greater than its Lowenheim-Skolem number. We study ... More
The quasi-state space of a C*-algebra is a topological quotient of the representation spaceApr 15 2013Jan 28 2015We show that for any C*-algebra $A$, a sufficiently large Hilbert space $H$ and a unit vector $\xi \in H$, the natural application $rep(A:H) \to Q(A)$, $\pi \mapsto \langle \pi(-)\xi,\xi \rangle$ is a topological quotient, where $rep(A:H)$ is the space ... More
Eigenvalues and Entropy of a Hitchin representationNov 19 2014Dec 18 2014We show that the critical exponent of a representation in the Hitchin component of $PSL(d,\mathbb{R})$ is bounded above, the least upper bound being attained only in the Fuchsian locus. This provides a rigid inequality for the area of a minimal surface ... More
Unsteady non-Newtonian hydrodynamics in granular gasesNov 18 2011Feb 07 2012The temporal evolution of a dilute granular gas, both in a compressible flow (uniform longitudinal flow) and in an incompressible flow (uniform shear flow), is investigated by means of the direct simulation Monte Carlo method to solve the Boltzmann equation. ... More
Collisional rates for the inelastic Maxwell model: application to the divergence of anisotropic high-order velocity moments in the homogeneous cooling stateJul 01 2011May 11 2012The collisional rates associated with the isotropic velocity moments $<V^{2r}>$ and the anisotropic moments $<V^{2r}V_i>$ and $<V^{2r}(V_iV_j-d^{-1}V^2\delta_{ij})>$ are exactly derived in the case of the inelastic Maxwell model as functions of the exponent ... More
Eigenvalues and Entropy of a Hitchin representationNov 19 2014Feb 13 2017We show that the critical exponent of a representation in the Hitchin component of $PSL(d,\mathbb{R})$ is bounded above, the least upper bound being attained only in the Fuchsian locus. This provides a rigid inequality for the area of a minimal surface ... More
The ternary Goldbach problemApr 08 2014Apr 12 2014The ternary Goldbach conjecture, or three-primes problem, states that every odd number $n$ greater than $5$ can be written as the sum of three primes. The conjecture, posed in 1742, remained unsolved until now, in spite of great progress in the twentieth ... More
Non-Newtonian Poiseuille flow of a gas in a pipeJun 05 2000The Bhatnagar-Gross-Krook kinetic model of the Boltzmann equation is solved for the steady cylindrical Poiseuille flow fed by a constant gravity field. The solution is obtained as a perturbation expansion in powers of the field (through fourth order) ... More
Energy Production Rates of Multicomponent Granular Gases of Rough Particles. A Unified View of Hard-Disk and Hard-Sphere SystemsSep 07 2018Granular gas mixtures modeled as systems of inelastic and rough particles, either hard disks on a plane or hard spheres, are considered. Both classes of systems are embedded in a three-dimensional space ($d=3$) but, while in the hard-sphere case the translational ... More
Driven and undriven states of multicomponent granular gases of inelastic and rough hard disks or spheresJan 31 2019Starting from a recent derivation of the energy production rates in terms of the number of translational and rotational degrees of freedom, a comparative study on different granular temperatures in gas mixtures of inelastic and rough disks or spheres ... More
An Alternative Derivation of the Analytic Expression of Transmission SpectraAug 16 2018Under some assumptions, an analytic expression for the transmission spectrum can be obtained, which can form the basis of atmospheric retrievals and allows insight on the degeneracies involved. In this Research Note we present an alternative derivation ... More
Indexed Dynamic Programming to boost Edit Distance and LCSS ComputationJun 12 2018There are efficient dynamic programming solutions to the computation of the Edit Distance from $S\in[1..\sigma]^n$ to $T\in[1..\sigma]^m$, for many natural subsets of edit operations, typically in time within $O(nm)$ in the worst-case over strings of ... More
The Value of A Statistical Life in Absence of Panel Data: What can we do?Mar 02 2016In this paper I show how reliable estimates of the Value of a Statistical Life (VSL) can be obtained using cross sectional data using Garen's instrumental variable (IV) approach. The increase in the range confidence intervals due to the IV setup can be ... More
ScratchR: Sharing User-generated Programmable MediaJul 05 2015In this paper, I describe a platform for sharing programmable media on the web called ScratchR. As the backbone of an on-line community of creative learners, ScratchR will give members access to an audience and inspirational ideas from each other. ScratchR ... More
Detection of a diffuse extended halo-like structure around 47 TucAug 21 2017We constructed for the first time a stellar density profile of 47 Tucanae (47 Tuc) out of $\sim$ 5.5 times its tidal radius ($r_t$) using high-quality deep $BV$ photometry. After carefully considering the influence of photometric errors, and Milky Way ... More
Bounding $S_n(t)$ on the Riemann hypothesisFeb 14 2017Let $S(t) = \tfrac{1}{\pi} \arg \zeta (\frac12 + it)$ be the argument of the Riemann zeta-function at the point $\tfrac12 + it$. For $n \geq 1$ and $t>0$ define its iterates \begin{equation*} S_n(t) = \int_0^t S_{n-1}(\tau) \,{\rm d}\tau\, + \delta_n\,, ... More