Results for "Bernardo Villarreal"

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Nilpotent $n$-tuples in $SU(2)$Nov 18 2016May 08 2019We describe the connected components of the space $\text{Hom}(\Gamma,SU(2))$ of homomorphisms for a discrete nilpotent group $\Gamma$. The connected components arising from homomorphisms with non-abelian image turn out to be homeomorphic to $\mathbb{RP}^3$. ... More
Cosimplicial Groups and Spaces of HomomorphismsJan 18 2016Jul 11 2016Let $G$ be a real linear algebraic group and $L$ a finitely generated cosimplicial group. We prove that the space of homomorphisms $Hom(L_n,G)$ has a homotopy stable decomposition for each $n\geq 1$. When $G$ is a compact Lie group, we show that the decomposition ... More
Commutative cocycles and stable bundles over surfacesJul 10 2018Commutative K-theory, a cohomology theory built from spaces of commuting matrices, has been explored in recent work of Adem, G\'{o}mez, Gritschacher, Lind, and Tillman. In this article, we use unstable methods to construct explicit representatives for ... More
Nilpotent $n$-tuples in $SU(2)$Nov 18 2016Jun 29 2018Let $F_n/\Gamma^{q+1}_n$ denote the free nilpotent group on $n$ generators of nilpotency class $q$ . We calculate the number of connected components of the spaces of homomorphisms $\text{Hom}(F_n/\Gamma^{q+1}_n,SU(2))$ arising from non-commuting $n$-tuples ... More
Nilpotent $n$-tuples in $SU(2)$Nov 18 2016Let $F_n/\Gamma^q_n$ denote the finitely generated free $q$-nilpotent group. We describe the connected components of the spaces of homomorphisms $Hom(F_n/\Gamma^q_n,SU(2))$, $Hom(F_n/\Gamma^q_n,SO(3))$ and $Hom(F_n/\Gamma^q_n,U(2))$. We also describe ... More
Commutative cocycles and stable bundles over surfacesJul 10 2018Mar 27 2019Commutative K-theory, a cohomology theory built from spaces of commuting matrices, has been explored in recent work of Adem, G\'{o}mez, Gritschacher, Lind, and Tillman. In this article, we use unstable methods to construct explicit representatives for ... More
Classifying spaces for commutativity of low-dimensional Lie groupsFeb 10 2018For each of the groups $G = O(2), SU(2), U(2)$, we compute the integral and $\mathbb{F}_2$-cohomology rings of $B_\text{com} G$ (the classifying space for commutativity of $G$), the action of the Steenrod algebra on the mod 2 cohomology, the homotopy ... More
Rees cones and monomial rings of matroidsJan 21 2006Apr 03 2011Using linear algebra methods we study certain algebraic properties of monomial rings and matroids. Let I be a monomial ideal in a polynomial ring over an arbitrary field. If the Rees cone of I is quasi-ideal, we express the normalization of the Rees algebra ... More
Normalization of monomial ideals and Hilbert functionsApr 27 2006Dec 25 2006We study the normalization of a monomial ideal, and show how to compute its Hilbert function (using Ehrhart polynomials) if the ideal is zero dimensional. A positive lower bound for the second coefficient of the Hilbert polynomial is shown.
Observables for Brownian motion on manifoldsDec 19 2012We study the geometrical influence on the Brownian motion over curved manifolds. We focus on the following intriguing question: what observables are appropriated to measure Brownian motion in curved manifolds? In particular, for those d-dimensional manifolds ... More
Nilmanifolds and their associated non local fieldsSep 28 2018Dec 03 2018For six dimensional nilmanifolds we build a module $\mathcal{H}$ of an affine Kac Moody vertex algebras. Then, we associate some logarithmic fields for the module $\mathcal{H}$ and we study their singularities. We also presented a physics motivation behind ... More
Unmixed bipartite graphsJun 20 2006Jul 29 2007In this note we give a combinatorial characterization of all the unmixed bipartite graphs.
Hyperbolicity, transitivity and the two-sided limit shadowing propertyJan 10 2013We explore the notion of two-sided limit shadowing property introduced by Pilyugin \cite{P1}. Indeed, we characterize the $C^1$-interior of the set of diffeomorphisms with such a property on closed manifolds as the set of transitive Anosov diffeomorphisms. ... More
Two characterizations of simple circulant tournamentsJul 13 2015The \textit{acyclic disconnection} $\overrightarrow{\omega }(D)$ (resp. the \textit{directed triangle free disconnection } $\overrightarrow{\omega }_{3}(D)$) of a digraph $D$ is defined as the maximum possible number of connected components of the underlying ... More
Group actions on dg-manifolds and Exact Courant algebroidsOct 26 2010Oct 14 2012Let G be a Lie group acting by diffeomorphisms on a manifold M and consider the image of T[1]G and T[1]M, of G and M respectively, in the category of differential graded manifolds. We show that the obstruction to lift the action of T[1]G on T[1]M to an ... More
On the Betti numbers of some Gorenstein idealsJun 20 1994Assume $R$ is a polynomial ring over a field and $I$ is a homogeneous Gorenstein ideal of codimension $g\ge3$ and initial degree $p\ge2$. We prove that the number of minimal generators $\nu(I_p)$ of $I$ that are in degree $p$ is bounded above by $\nu_0={p+g-1\choose ... More
Combinatorics of Cremona monomial mapsApr 26 2009Apr 07 2011One studies Cremona monomial maps by combinatorial means. Among the results is a simple integer matrix theoretic proof that the inverse of a Cremona monomial map is also defined by monomials of fixed degree, and moreover, the set of monomials defining ... More
Complete intersection vanishing ideals on sets of clutter type over finite fieldsMar 04 2015In this paper we give a classification of complete intersection vanishing ideals on parameterized sets of clutter type over finite fields.
Edge ideals: algebraic and combinatorial propertiesDec 24 2010Mar 29 2011Let C be a clutter and let I(C) be its edge ideal. This is a survey paper on the algebraic and combinatorial properties of R/I(C) and C, respectively. We give a criterion to estimate the regularity of R/I(C) and apply this criterion to give new proofs ... More
Symmetry operators and decoupled equations for linear fields on black hole spacetimesOct 03 2016Oct 11 2016In the class of vacuum Petrov type D spacetimes with cosmological constant, which includes the Kerr-(A)dS black hole as a particular case, we find a set of four-dimensional operators that, when composed {\em off shell} with the Dirac, Maxwell and linearized ... More
Symmetry operators and decoupled equations for linear fields on black hole spacetimesOct 03 2016Mar 27 2017In the class of vacuum Petrov type D spacetimes with cosmological constant, which includes the Kerr-(A)dS black hole as a particular case, we find a set of four-dimensional operators that, when composed {\em off shell} with the Dirac, Maxwell and linearized ... More
Managing large-scale scientific hypotheses as uncertain and probabilistic dataJan 21 2015Feb 12 2015In view of the paradigm shift that makes science ever more data-driven, in this thesis we propose a synthesis method for encoding and managing large-scale deterministic scientific hypotheses as uncertain and probabilistic data. In the form of mathematical ... More
On the Classification of Pointed Fusion Categories up to weak Morita EquivalenceNov 17 2015Mar 11 2017A pointed fusion category is a rigid tensor category with finitely many isomorphism classes of simple objects which moreover are invertible. Two tensor categories $C$ and $D$ are weakly Morita equivalent if there exists an indecomposable right module ... More
On the Classification of Pointed Fusion Categories up to weak Morita EquivalenceNov 17 2015A pointed fusion category is a rigid tensor category with finitely many isomorphism classes of simple objects which moreover are invertible. Two tensor categories $C$ and $D$ are weakly Morita equivalent if there exists an indecomposable right module ... More
High-temperature cuprate superconductors studied by x-ray Compton scattering and positron annihilation spectroscopiesJun 25 2013The bulk Fermi surface in an overdoped ($x = 0.3$) single crystal of La$_{2-x}$Sr$_{x}$CuO$_{4}$ has been observed by using x-ray Compton scattering. This momentum density technique also provides a powerful tool for directly seeing what the dopant Sr ... More
Orbifold Cohomology of the Symmetric ProductSep 18 2001Chen and Ruan's orbifold cohomology of the symmetric product of a complex manifold is calculated. An isomorphism of rings (up to a change of signs) $H_{orb}^*(X^n/S_n;\complex) \cong H^*(X^{[n]};\complex)$ between the orbifold cohomology of the symmetric ... More
Unruh Duality and Maximum Acceleration in String TheoryJan 25 2019Feb 07 2019It is argued that the Unruh effect may be interpreted as a duality of a theory on different backgrounds. This issue is revisited in String Theory in the path integral formalism. By using T-duality and the Unruh effect, the T-dual transformation for acceleration ... More
Conformal invariance, complex structures, and the Teukolsky connectionMay 29 2018We show that the Teukolsky connection, which defines generalized wave operators governing the behavior of massless fields on Einstein spacetimes of Petrov type D, has its origin in a distinguished conformally and GHP covariant connection on the conformal ... More
Axially symmetric membranes with polar tethersAug 09 2006Jan 25 2007Axially symmetric equilibrium configurations of the conformally invariant Willmore energy are shown to satisfy an equation that is two orders lower in derivatives of the embedding functions than the equilibrium shape equation, not one as would be expected ... More
Vanishing ideals over finite fieldsFeb 19 2015Jun 19 2016Let $\mathbb{F}_q$ be a finite field, let $\mathbb{X}$ be a subset of a projective space ${\mathbb P}^{s-1}$, over the field $\mathbb{F}_q$, parameterized by rational functions, and let $I(\mathbb{X})$ be the vanishing ideal of $\mathbb{X}$. The main ... More
Inverted catenoids, curvature singularities and tethered membranesFeb 14 2007If a catenoid is inverted in any interior point, a deflated compact geometry is obtained which touches at two points (its poles). The catenoid is a minimal surface and, as such, is an equilibrium shape of a symmetric fluid membrane. The conformal symmetry ... More
Cohen-Macaulay, Shellable and unmixed clutters with a perfect matching of König typeAug 22 2007Nov 06 2007Let $\mathcal{C}$ be a clutter with a perfect matching $e_1,...,e_g$ of K\"onig type and let $\Delta_\mathcal{C}$ be the Stanley-Reisner complex of the edge ideal of $\mathcal{C}$. If all c-minors of $\mathcal{C}$ have a free vertex and $\mathcal{C}$ ... More
Go game formal revealing by Ising modelOct 19 2017Go gaming is a struggle for territory control between rival, black and white, stones on a board. We model the Go dynamics in a game by means of the Ising model whose interaction coefficients reflect essential rules and tactics employed in Go to build ... More
Active motion on curved surfacesDec 13 2017A theoretical analysis of active motion on curved surfaces is presented in terms of a generalization of the Telegrapher's equation. Such generalized equation is explicitly derived as the polar approximation of the hierarchy of equations obtained from ... More
Stellar, gas and dark matter content of barred galaxiesNov 14 2016We select a sample of galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) where galaxies are classified, through visual inspection, as hosting strong bars, weak bars or as unbarred galaxies, and make use of HI mass and kinematic information ... More
Persistently Exciting Tube MPCMay 21 2015This paper presents a new approach to deal with the dual problem of system identification and regulation. The main feature consists of breaking the control input to the system into a regulator part and a persistently exciting part. The former is used ... More
Classification of Pointed Fusion Categories of dimension 8 up to weak Morita EquivalenceJul 11 2017In this paper we give a complete classification of pointed fusion categories over $\mathbb{C}$ of global dimension 8. We first classify the equivalence classes of pointed fusion categories of dimension 8, and then we proceed to determine which of these ... More
Orbifold Virtual Cohomology of the Symmetric ProductFeb 14 2007Nov 19 2007The virtual cohomology of an orbifold is a ring structure on the cohomology of the inertia orbifold whose product is defined via the pull-push formalism and the Euler class of the excess intersection bundle. In this paper we calculate the virtual cohomology ... More
Instability of asymptotically anti de Sitter black holes under Robin conditions at the timelike boundaryNov 10 2016The static region outside the event horizon of an asymptotically anti de Sitter black hole has a conformal timelike boundary $\mathscr{I}$, the evolution from initial data of linear fields satisfying hyperbolic equations is a well posed problem only after ... More
A short note on the monotonicity of the Erlang C formula in the Halfin-Whitt regimeDec 15 2011We prove a monotonicity condition satisfied by the Erlang C formula when computed in the Halfin-Whitt regime. This property was recently conjectured in Janssen et al. [2011].
Topological properties of the unitary groupJul 07 2014We show that the strong operator topology, the weak operator topology and the compact-open topology agree on the space of unitary operators of a infinite dimensional separable Hilbert space. Moreover, we show that the unitary group endowed with any of ... More
Stringy product on twisted orbifold K-theory for abelian quotientsJun 21 2007Feb 15 2008In this paper we present a model to calculate the stringy product on twisted orbifold K-theory of Adem-Ruan-Zhang for abelian complex orbifolds. In the first part we consider the non-twisted case on an orbifold presented as the quotient of a manifold ... More
Extended manifolds and extended equivariant cohomologyAug 13 2006Sep 27 2007We define the category of manifolds with extended tangent bundles, we study their symmetries and we consider the analogue of equivariant cohomology for actions of Lie groups in this category. We show that when the action preserves the splitting of the ... More
Generic Gaussian idealsOct 04 2002The content of a polynomial $f(t)$ is the ideal generated by its coefficients. Our aim here is to consider a beautiful formula of Dedekind-Mertens on the content of the product of two polynomials, to explain some of its features from the point of view ... More
Optimal investment under behavioural criteria in incomplete diffusion market modelsJan 07 2015The most commonly accepted model for investors' preferences is expected utility theory. More recently, other theories have emerged and pose new challenges to mathematics. The present paper treats preferences of cumulative prospect theory (CPT), where ... More
Shellable graphs and sequentially Cohen-Macaulay bipartite graphsJan 10 2007Nov 06 2007Associated to a simple undirected graph G is a simplicial complex whose faces correspond to the independent sets of G. We call a graph G shellable if this simplicial complex is a shellable simplicial complex in the non-pure sense of Bjorner-Wachs. We ... More
A Search for Extended Radio Sources in 1.3 sr of the VLA Sky Survey (VLASS)Aug 22 2018We report preliminary results of a visual inspection of ~4300 deg$^2$ covered by 4414 images of the 3-GHz VLA Sky Survey (VLASS, epoch 1.1) in search of extended radio structures. Over 7600 positions were registered, and for a subset of 270 of the most ... More
The Degree and regularity of vanishing ideals of algebraic toric sets over finite fieldsOct 10 2011Jun 21 2013Let X* be a subset of an affine space A^s, over a finite field K, which is parameterized by the edges of a clutter. Let X and Y be the images of X* under the maps x --> [x] and x --> [(x,1)] respectively, where [x] and [(x,1)] are points in the projective ... More
Symbolic Rees algebras, vertex covers and irreducible representations of Rees conesDec 08 2007Mar 04 2009Let G be a simple graph and let J be its ideal of vertex covers. We give a graph theoretical description of the irreducible b-vertex covers of G, i.e., we describe the minimal generators of the symbolic Rees algebra of J. Then we study the irreducible ... More
Optimal investment under behavioural criteria -- a dual approachMay 15 2014Jun 20 2014We consider a discrete-time, generically incomplete market model and a behavioural investor with power-like utility and distortion functions. The existence of optimal strategies in this setting has been shown in a previous paper under certain conditions ... More
Exact results for Casimir forces using Surface Impedance: Nonlocal MediaJun 20 2003We show that exact results are obtained for the calculation of Casimir forces between arbitrary materials using the concept of surface impedances, obtaining in a trivial way the force in the limit of perfect conductors and also Lifshitz formula in the ... More
Complete intersections in binomial and lattice idealsMay 03 2012Jun 11 2013For the family of graded lattice ideals of dimension 1, we establish a complete intersection criterion in algebraic and geometric terms. In positive characteristic, it is shown that all ideals of this family are binomial set theoretic complete intersections. ... More
Ring graphs and complete intersection toric idealsMar 30 2006Mar 17 2009We study the family of graphs whose number of primitive cycles equals its cycle rank. It is shown that this family is precisely the family of ring graphs. Then we study the complete intersection property of toric ideals of bipartite graphs and oriented ... More
Higher-order phase transitions with line-tension effectNov 09 2009The behavior of energy minimizers at the boundary of the domain is of great importance in the Van de Waals-Cahn-Hilliard theory for fluid-fluid phase transitions, since it describes the effect of the container walls on the configuration of the liquid. ... More
Disjunctive Probabilistic Modal Logic is Enough for Bisimilarity on Reactive Probabilistic SystemsJan 22 2016Apr 09 2016Larsen and Skou characterized probabilistic bisimilarity over reactive probabilistic systems with a logic including true, negation, conjunction, and a diamond modality decorated with a probabilistic lower bound. Later on, Desharnais, Edalat, and Panangaden ... More
Unified quantum density matrix description of coherence and polarizationJun 03 2016The properties of coherence and polarization of light has been the subject of intense investigations and form the basis of many technological applications. These concepts which historically have been treated independently can now be formulated under a ... More
Distributed Model Predictive Control Using a Chain of TubesMar 07 2016A new distributed MPC algorithm for the regulation of dynamically coupled subsystems is presented in this paper. The current control action is computed via two robust controllers working in a nested fashion. The inner controller builds a nominal reference ... More
On Polymorphic Sessions and Functions: A Tale of Two (Fully Abstract) EncodingsNov 02 2017Jan 25 2018This work exploits the logical foundation of session types to determine what kind of type discipline for the pi-calculus can exactly capture, and is captured by, lambda-calculus behaviours. Leveraging the proof theoretic content of the soundness and completeness ... More
Unified quantum density matrix description of coherence and polarizationJun 03 2016May 10 2017The properties of coherence and polarization of light has been the subject of intense investigations and form the basis of many technological applications. These concepts which historically have been treated independently can now be formulated under a ... More
Small field inflation in ${\cal N}=1$ supergravity with a single chiral superfieldMay 06 2016Jun 24 2016We consider "new inflation" inflationary models at small fields, embedded in minimal ${\cal N}=1$ supergravity with a single chiral superfield. Imposing a period of inflation compatible with experiment severely restricts possible models, classified in ... More
Proposed parameter-free model for interpreting the measured positron annihilation spectra of materials using a generalized gradient approximationApr 13 2015Positron annihilation spectroscopy is often used to analyze the local electronic structure of materials of technological interest. Reliable theoretical tools are crucial to interpret the measured spectra. Here, we propose a parameter-free gradient correction ... More
A hybridizable discontinuous Galerkin method for fractional diffusion problemsSep 25 2014We study the use of the hybridizable discontinuous Galerkin (HDG) method for numerically solving fractional diffusion equations of order $-\alpha$ with $-1<\alpha<0$. For exact time-marching, we derive optimal algebraic error estimates {assuming} that ... More
Calibration and Performance of the ATLAS Tile CalorimeterMay 02 2013The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most central region of the ATLAS experiment at the LHC. It is a key detector for the measurement of hadrons, jets, tau leptons and missing transverse energy. The TileCal calibration ... More
Managing large-scale scientific hypotheses as uncertain and probabilistic data with support for predictive analyticsMay 22 2014May 17 2015The sheer scale of high-resolution raw data generated by simulation has motivated non-conventional approaches for data exploration referred as `immersive' and `in situ' query processing of the raw simulation data. Another step towards supporting scientific ... More
Novel layout for reflective arrayed waveguide gratings based on Sagnac loop reflectors with custom spectral responseFeb 18 2014A novel layout for a reflective Arrayed Waveguide Grating is presented in this paper. The device consists of one half of a regular AWG where each arm waveguide in the array is terminated with a phase shifter and a Sagnac loop reflector. The theoretical ... More
Inertia Orbifolds, Configuration Spaces and the Ghost Loop SpaceOct 15 2002Dec 13 2002In this paper we define and study the "ghost loop orbifold" of an orbifold $X$ consisting of those loops that remain constant in the coarse moduli space of $X$. We construct a configuration space model for the ghost loop orbifold using an idea of G. Segal. ... More
Loop Groupoids, Gerbes, and Twisted Sectors on OrbifoldsOct 18 2001Oct 30 2002The purpose of this paper is to introduce the notion of loop groupoid associated to a groupoid. After studying the general properties of the loop groupoid, we show how this notion provides a very natural geometric interpretation for the twisted sectors ... More
Gerbes over Orbifolds and Twisted K-theoryMay 05 2001Mar 19 2002In this paper we construct an explicit geometric model for the group of gerbes over an orbifold $X$. We show how from its curvature we can obtain its characteristic class in $H^3(X)$ via Chern-Weil theory. For an arbitrary gerbe $\LL$, a twisting $\Korb{\LL}(X)$ ... More
Clustered Volatility in Multiagent DynamicsMar 01 1995Large distributed multiagent systems are characterized by vast numbers of agents trying to gain access to limited resources in an unpredictable environment. Agents in these system continuously switch strategies in order to opportunistically find improvements ... More
Diversity and Collective ActionJul 27 1993Aug 12 1993We elucidate the dynamics of ongoing collective action among intentional agents with diverse beliefs and imperfect information. Their decisions on whether or not to contribute to the collective good depend not only on the past but also on their expectations ... More
Machine Learning simulates Agent-Based ModelDec 12 2017Running agent-based models (ABMs) is a burdensome computational task, specially so when considering the flexibility ABMs intrinsically provide. This paper uses a bundle of model configuration parameters along with obtained results from a validated ABM ... More
Holographic cosmology from "dimensional reduction" of ${\cal N}=4$ SYM vs. $AdS_5\times S^5$Dec 18 2018We propose a way to obtain holographic cosmology models for 3+1 dimensional cosmologies vs. 3 dimensional field theories from a "dimensional reduction" procedure, obtained by integrating over the time direction, of (modifed) standard holographic duals ... More
Distributed Model Predictive Control Using a Chain of TubesMar 07 2016Mar 27 2017A new distributed MPC algorithm for the regulation of dynamically coupled subsystems is presented in this paper. The current control action is computed via two robust controllers working in a nested fashion. The inner controller builds a nominal reference ... More
Persistently Exciting Tube MPCMay 21 2015Mar 27 2017This paper presents a new approach to deal with the dual problem of system identification and regulation. The main feature consists of breaking the control input to the system into a regulator part and a persistently exciting part. The former is used ... More
Volatility Effects on the Escape Time in Financial Market ModelsOct 08 2008We shortly review the statistical properties of the escape times, or hitting times, for stock price returns by using different models which describe the stock market evolution. We compare the probability function (PF) of these escape times with that obtained ... More
Improved generalized gradient approximation for positron states in solidsAug 27 2013Jul 14 2014Several first-principles calculations of positron-annihilation characteristics in solids have added gradient corrections to the local-density approximation within the theory by Arponen and Pajanne [Ann. Phys. (N.Y.) 121, 343 (1979)] since this theory ... More
Multimethods and separate static typechecking in a language with C++-like object modelMay 31 2000The goal of this paper is the description and analysis of multimethod implementation in a new object-oriented, class-based programming language called OOLANG. The implementation of the multimethod typecheck and selection, deeply analyzed in the paper, ... More
Enhancement of Compton Scattering by an Effective Coupling ConstantMay 30 2010Aug 08 2011A robust thermodynamic argument shows that a small reduction of the effective coupling constant $\alpha$ of QED greatly enhances the Compton scattering cross section and that the Thomson scattering length is connected to a fundamental scale $\lambda$. ... More
Modeling tax distribution in metropolitan regions with PolicySpaceDec 31 2018Brazilian executive body has consistently vetoed legislative initiatives easing creation and emancipation of municipalities. The literature lists evidence of the negative results of municipal fragmentation, especially so for metropolitan regions. In order ... More
Proposal for a Direct Measurement of the von Neumann Entropy and the Relative Entropy of CoherenceDec 10 2018Feb 25 2019Quantum coherence is the most distinguished signature of quantum mechanics, also recognized to be an essential resource for many promising quantum technologies, playing a central role in phenomena related to quantum information science, quantum thermodynamics ... More
Positively n-expansive homeomorphisms and the L-shadowing propertyJul 28 2017Oct 25 2017We discuss further the dynamics of n-expansive homeomorphisms with the shadowing property, started in [7]. The L-shadowing property is defined and the dynamics of n-expansive homeomorphisms with such property is explored. In particular, we prove that ... More
Devising superconvergent HDG methods with symmetric approximate stresses for linear elasticity by $M$-decompositionsApr 14 2017We propose a new tool, which we call $M$-decompositions, for devising superconvergent hybridizable discontinuous Galerkin (HDG) methods and hybridized-mixed methods for linear elasticity with strongly symmetric approximate stresses on unstructured polygonal/polyhedral ... More
Stellar, gas and dark matter content of barred galaxiesNov 14 2016Nov 21 2016We select a sample of galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) where galaxies are classified, through visual inspection, as hosting strong bars, weak bars or as unbarred galaxies, and make use of HI mass and kinematic information ... More
N-expansive homeomorphisms with the shadowing propertyApr 03 2016We discuss the dynamics of $n$-expansive homeomorphisms with the shadowing property defined on compact metric spaces. For every $n\in\mathbb{N}$, we exhibit an $n$-expansive homeomorphism, which is not $(n-1)$-expansive, has the shadowing property and ... More
On homeomorphisms with the two-sided limit shadowing propertyFeb 04 2014We prove that the two-sided limit shadowing property is among the strongest known notions of pseudo-orbit tracing. It implies shadowing, average shadowing, asymptotic average shadowing and specification properties. We also introduce a weaker notion that ... More
Combinatorics of symbolic Rees algebras of edge ideals of cluttersMay 07 2009Aug 14 2010Let C be a clutter and let I be its edge ideal. We present a combinatorial description of the minimal generators of the symbolic Rees algebra Rs(I) of I. It is shown that the minimal generators of Rs(I) are in one to one correspondence with the irreducible ... More
Linear codes over signed graphsApr 20 2019We give formulas, in terms of graph theoretical invariants, for the minimum distance and the generalized Hamming weights of the linear code generated by the rows of the incidence matrix of a signed graph over a finite field, and for those of its dual ... More
Perfect and near perfect adaptation in a model of bacterial chemotaxisNov 20 2002The signaling apparatus mediating bacterial chemotaxis can adapt to a wide range of persistent external stimuli. In many cases, the bacterial activity returns to its pre-stimulus level exactly and this "perfect adaptability" is robust against variations ... More
Hair-dressing Horndeski: an approach to hairy solutions in cubic Horndeski gravityFeb 13 2019In obtaining exact solutions in gravitational theories containing arbitrary model functions, such as Horndeski gravity, one usually starts by prescribing the model functions of the theory and then goes on to solving their corresponding field equations. ... More
Generalized Banach contraction in probabilistic metric/normed spacesJun 11 2007In this paper, we present the generalization of B-contraction and C-contraction due to Sehgal and Hicks respectively. We also study some properties of C-contraction in probabilistic metric space.
A note on Rees algebras and the MFMC propertyNov 11 2005Mar 09 2007We study irreducible representations of Rees cones and characterize the max-flow min-cut property of clutters in terms of the normality of Rees algebras and the integrality of certain polyhedra. Then we present some applications to combinatorial optimization ... More
Bsmooth: Learning from user feedback to disambiguate query terms in interactive data retrievalOct 15 2016There is great interest in supporting imprecise queries over databases today. To support such queries, the system is typically required to disambiguate parts of the user-specified query against the database, using whatever resources are intrinsically ... More
Comparative Advantage Driven Resource Allocation for Virtual Network FunctionsMar 12 2016As Communication Service Providers (CSPs) adopt the Network Function Virtualization (NFV) paradigm, they need to transition their network function capacity to a virtualized infrastructure with different Network Functions running on a set of heterogeneous ... More
Hair-dressing Horndeski: an approach to hairy solutions in cubic Horndeski gravityFeb 13 2019Apr 01 2019In obtaining exact solutions in gravitational theories containing arbitrary model functions, such as Horndeski gravity, one usually starts by prescribing the model functions of the theory and then goes on to solving their corresponding field equations. ... More
Finding Communities in Linear Time: A Physics ApproachOct 26 2003We present a method that allows for the discovery of communities within graphs of arbitrary size in times that scale linearly with their size. This method avoids edge cutting and is based on notions of voltage drops across networks that are both intuitive ... More
How marketing vocabulary was evolving from 2005 to 2014? An illustrative application of statistical methods on text miningFeb 05 2016Here a collection of 1169 abstracts, which corresponds to articles that the Journal of Marketing Research has published from 2005 to 2014, are analysed under a novel approach. We apply several statistical methods, such as Principal Components Analysis ... More
Minimum distance functions of complete intersectionsJan 28 2016Oct 24 2017We study the footprint function, with respect to a monomial order, of complete intersection graded ideals in a polynomial ring with coefficients in a field. For graded ideals of dimension one, whose initial ideal is a complete intersection, we give a ... More
Regularity and algebraic properties of certain lattice idealsJan 17 2013Dec 19 2013We study the regularity and the algebraic properties of certain lattice ideals. We establish a map I --> I\~ between the family of graded lattice ideals in an N-graded polynomial ring over a field K and the family of graded lattice ideals in a polynomial ... More
Indices of Normalization of IdealsJun 23 2010Several numerical indices that control the normalization of ideals are introduced and some relationships among them are derived.
Contraction and incremental stability of switched Carathéodory systems using multiple normsFeb 21 2015Mar 01 2016In this paper, incremental exponential asymptotic stability of a class of switched Carath\'{e}odory nonlinear systems is studied based on the novel concept of measure of switched matrices via multiple norms and the transaction coefficients between these ... More