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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

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

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

Intrinsic and extrinsic measure for Brownian motionFeb 16 2014Based upon the Smoluchowski equation on curved manifolds three physical observables are considered for the Brownian displacement, namely, geodesic displacement, $s$, Euclidean displacement, $\delta{\bf R}$, and projected displacement $\delta{\bf R}_{\perp}$. ... More

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

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

Product Anosov diffeomorphisms and the two-sided limit shadowing propertySep 16 2015We characterize product Anosov diffeomorphisms in terms of the two-sided limit shadowing property. It is proved that an Anosov diffeomorphism is a product Anosov diffeomorphism if and only if any lift to the universal covering has the unique two-sided ... More

Markovian Testing Equivalence and Exponentially Timed Internal ActionsDec 10 2009In the theory of testing for Markovian processes developed so far, exponentially timed internal actions are not admitted within processes. When present, these actions cannot be abstracted away, because their execution takes a nonzero amount of time and ... More

Show me the material evidence: Initial experiments on evaluating hypotheses from user-generated multimedia dataNov 11 2016Subjective questions such as `does neymar dive', or `is clinton lying', or `is trump a fascist', are popular queries to web search engines, as can be seen by autocompletion suggestions on Google, Yahoo and Bing. In the era of cognitive computing, beyond ... More

Information Societies and Digital DividesJul 17 2008The book argues ICT are part of the set of goods and services that determine quality of life, social inequality and the chances for economic development. Therefore understanding the digital divide demands a broader discussion of the place of ICT within ... 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

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

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

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

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

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

Automatic Hardware Synthesis for a Hybrid Reconfigurable CPU Featuring Philips CPLDsNov 12 1998A high-level architecture of a Hybrid Reconfigurable CPU, based on a Philips-supported core processor, is introduced. It features the Philips XPLA2 CPLD as a reconfigurable functional unit. A compilation chain is presented, in which automatic implementation ... More

Weak Markovian Bisimulation Congruences and Exact CTMC-Level Aggregations for Concurrent ProcessesJul 04 2012We have recently defined a weak Markovian bisimulation equivalence in an integrated-time setting, which reduces sequences of exponentially timed internal actions to individual exponentially timed internal actions having the same average duration and execution ... More

On the Expressiveness of Markovian Process Calculi with Durational and Durationless ActionsJun 08 2010Several Markovian process calculi have been proposed in the literature, which differ from each other for various aspects. With regard to the action representation, we distinguish between integrated-time Markovian process calculi, in which every action ... More

Asymptotic Behaviour and Ratios of Complexity in Cellular AutomataApr 10 2013Aug 21 2015We study the asymptotic behaviour of symbolic computing systems, notably one-dimensional cellular automata (CA), in order to ascertain whether and at what rate the number of complex versus simple rules dominate the rule space for increasing neighbourhood ... More

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

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.

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

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

Algebraic and combinatorial properties of ideals and algebras of uniform clutters of TDI systemsJan 09 2008May 27 2009Let C be a uniform clutter, i.e., all the edges of C have the same size, and let A be the incidence matrix of C. We denote the column vectors of A by v1,...,vq. The vertex covering number of C, denoted by g, is the smallest number of vertices in any minimal ... More

Computing the degree of a lattice ideal of dimension oneJun 09 2012Jan 04 2014We show that the degree of a graded lattice ideal of dimension 1 is the order of the torsion subgroup of the quotient group of the lattice. This gives an efficient method to compute the degree of this type of lattice ideals.

Blowup algebras of square-free monomial ideals and some links to combinatorial optimization problemsSep 21 2006Jan 27 2009Let I=(x^{v_1},...,x^{v_q} be a square-free monomial ideal of a polynomial ring K[x_1,...,x_n] over an arbitrary field K and let A be the incidence matrix with column vectors {v_1},...,{v_q}. We will establish some connections between algebraic properties ... 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

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

Diffusion in Flashing Periodic PotentialsOct 07 2005The one-dimensional overdamped Brownian motion in a symmetric periodic potential modulated by external time-reversible noise is analyzed. The calculation of the effective diffusion coefficient is reduced to the mean first passage time problem. We derive ... 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

Holonomy for Gerbes over OrbifoldsJul 09 2003In this paper we compute explicit formulas for the holonomy map for a gerbe with connection over an orbifold. We show that the holonomy descends to a transgression map in Deligne cohomology. We prove that this recovers both the inner local systems in ... More

Extinction statistics in N random interacting speciesOct 05 2008A randomly interacting N-species Lotka-Volterra system in the presence of a Gaussian multiplicative noise is analyzed. The investigation is focused on the role of this external noise into the statistical properties of the extinction times of the populations. ... More

Equivariant principal bundles and their classifying spacesApr 17 2013Jan 09 2014We consider \Gamma-equivariant principal G-bundles over proper \Gamma-CW-complexes with prescribed family of local representations. We construct and analyze their classifying spaces for locally compact, second countable topological groups with finite ... More

Discussion of "Objective Priors: An Introduction for Frequentists" by M. GhoshAug 17 2011Discussion of "Objective Priors: An Introduction for Frequentists" by M. Ghosh [arXiv:1108.2120]

Comment on "Harold Jeffreys's Theory of Probability Revisited"Jan 18 2010Comment on "Harold Jeffreys's Theory of Probability Revisited" [arXiv:0804.3173]

Finite and countable infinite products of Probabilistic Normed SpacesApr 08 2004In this work we first give for PN spaces results parallel to those obtained by Egbert for the product of PM spaces, and generalize results by Alsina and Schweizer in order to study non-trivial products and the product of $m$-- transforms of several PN ... More

A systematic construction of finite element commuting exact sequencesApr 30 2016We present a systematic construction of finite element exact sequences with a commuting diagram for the de Rham complex in one-, two- and three-space dimensions. We apply the construction in two-space dimensions to rediscover two families of exact sequences ... More

A Spatial-Epistemic Logic for Reasoning about Security ProtocolsFeb 28 2011Reasoning about security properties involves reasoning about where the information of a system is located, and how it evolves over time. While most security analysis techniques need to cope with some notions of information locality and knowledge propagation, ... More

Organizational Fluidity and Sustainable CooperationJul 27 1993Aug 12 1993We show that fluid organizations display higher levels of cooperation than attainable by groups with either a fixed social structure or lacking one altogether. By moving within the organization, individuals cause restructurings that facilitate cooperation. ... More

$Υ$-DB: Managing scientific hypotheses as uncertain dataMay 19 2014In view of the paradigm shift that makes science ever more data-driven, we consider deterministic scientific hypotheses as uncertain data. This vision comprises a probabilistic database (p-DB) design methodology for the systematic construction and management ... More

Differential Characters on Orbifolds and String Connections INov 02 2003In this paper we introduce the Cheeger-Simons cohomology of a global quotient orbifold. We prove that the Cheeger-Simons cohomology of the orbifold is isomorphic to its Beilinson-Deligne cohomology. Furthermore we construct a string connection (\`{a} ... More

Deligne Cohomology for Orbifolds, discrete torsion and B-fieldsJan 23 2002Apr 25 2002In this paper we introduce the concept of Deligne cohomology of an orbifold. We prove that the third Deligne cohomology group of a smooth \'{e}tale groupoid classify gerbes with connection over the groupoid. We argue that the $B$-field and the discrete ... More

A Top-Down Account of Linear Canonical TransformsJun 06 2012We contend that what are called Linear Canonical Transforms (LCTs) should be seen as a part of the theory of unitary irreducible representations of the '2+1' Lorentz group. The integral kernel representation found by Collins, Moshinsky and Quesne, and ... More

Analytical estimation of the Earth's magnetic field scaleDec 08 2012Oct 23 2015In this paper we analytically estimate the magnetic field scale of planets with physical core conditions similar to that of Earth from a statistical point of view. We evaluate the magnetic field on the basis of the physical parameters of the center 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

Petrov type of linearly perturbed type D spacetimesFeb 25 2015We show that a spacetime satisfying the linearized vacuum Einstein equations around a type D background is generically of type I, and that the splittings of the Principal Null Directions (PNDs) and of the degenerate eigenvalue of the Weyl tensor are non ... 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Local Controls for Large Assemblies of Nonlinear ElementsApr 22 1994We introduce a set of local procedures that are capable of controlling distributed systems that exhibit complex dynamical behavior. These local controllers need only perturb local parameters and use local information about the state of the system. Besides ... 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

Generalized Wiener Process and Kolmogorov's Equation for Diffusion induced by Non-Gaussian Noise SourceMay 11 2005We show that the increments of generalized Wiener process, useful to describe non-Gaussian white noise sources, have the properties of infinitely divisible random processes. Using functional approach and the new correlation formula for non-Gaussian white ... More

Design-theoretic encoding of deterministic hypotheses as constraints and correlations into U-relational databasesNov 19 2014In view of the paradigm shift that makes science ever more data-driven, in this paper we consider deterministic scientific hypotheses as uncertain data. In the form of mathematical equations, hypotheses symmetrically relate aspects of the studied phenomena. ... More

A note on the complexity of the causal ordering problemAug 24 2015Jun 13 2016In this note we provide a concise report on the complexity of the causal ordering problem, originally introduced by Simon to reason about causal dependencies implicit in systems of mathematical equations. We show that Simon's classical algorithm to infer ... More

Expected-Delay-Summing Weak Bisimilarity for Markov AutomataSep 29 2015A new weak bisimulation semantics is defined for Markov automata that, in addition to abstracting from internal actions, sums up the expected values of consecutive exponentially distributed delays possibly intertwined with internal actions. The resulting ... More

Disjunctive Probabilistic Modal Logic is Enough for Bisimilarity on Reactive Probabilistic SystemsJan 22 2016Oct 24 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

Topological properties of spaces of projective unitary representationsNov 20 2015Aug 05 2016Let $G$ be a compact and connected Lie group and $PU(\mathcal H)$ be the group of projective unitary operators on a separable Hilbert space $\mathcal H$ endowed with the strong operator topology. We study the space $hom_{st}(G, PU(\mathcal H))$ of continuous ... 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

Algebraic methods for parameterized codes and invariants of vanishing ideals over finite fieldsJan 09 2010Sep 24 2010Let K be a finite field with q elements and let X be a subset of a projective space P^{s-1}, over the field K, which is parameterized by Laurent monomials. Let I(X) be the vanishing ideal of X. Some of the main contributions of this paper are in determining ... 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

Thermodynamics of a quantized electromagnetic field in rectangular cavities with perfectly conducting wallsAug 18 2005The thermodynamical properties of a quantized electromagnetic field inside a box with perfectly conducting walls are studied using a regularization scheme that permits to obtain finite expressions for the thermodynamic potentials. The source of ultraviolet ... 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

Critical Phenomena and Diffusion in Complex SystemsOct 08 2008Editorial of the International Conference on Critical Phenomena and Diffusion in Complex Systems held on 5--7 December, 2006 in Nizhniy Novgorod State University, Russia and was dedicated to the memory and 80th anniversary of Professor Askold N. Malakhov. ... More

On the equivarant de-Rham cohomology for non-compact Lie groupsJul 07 2014Feb 03 2015Let $G$ be a connected and non-necessarily compact Lie group acting on a connected manifold $M$. In this short note we announce the following result: for a $G$-invariant closed differential form on $M$, the existence of a closed equivariant extension ... 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

Information Relaxation is UltradiffusiveOct 09 2013Mar 19 2014We investigate how the overall response to a piece of information (a story or an article) evolves and relaxes as a function of time in social networks like Reddit, Digg and Youtube. This response or popularity is measured in terms of the number of votes/comments ... 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.

Complete intersection vanishing ideals on degenerate tori over finite fieldsJul 01 2012Dec 21 2012We study the complete intersection property and the algebraic invariants (index of regularity, degree) of vanishing ideals on degenerate tori over finite fields. We establish a correspondence between vanishing ideals and toric ideals associated to numerical ... 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

Communities of Practice: Performance and EvolutionOct 26 1994Oct 28 1994We present a detailed model of collaboration in communities of practice and we examine its dynamical consequences for the group as a whole. We establish the existence of a novel mechanism that allows the community to naturally adapt to growth, specialization, ... More

Optimizing Traffic FlowSep 29 1998We present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. The method exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient ... More

How Random are Online Social Interactions?Jul 16 2012Jul 19 2012The massive amounts of data that social media generates has facilitated the study of online human behavior on a scale unimaginable a few years ago. At the same time, the much discussed apparent randomness with which people interact online makes it appear ... More

Long Trend Dynamics in Social MediaSep 08 2011Dec 20 2011A main characteristic of social media is that its diverse content, copiously generated by both standard outlets and general users, constantly competes for the scarce attention of large audiences. Out of this flood of information some topics manage to ... 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

Constructive Provability LogicMay 29 2012We present constructive provability logic, an intuitionstic modal logic that validates the L\"ob rule of G\"odel and L\"ob's provability logic by permitting logical reflection over provability. Two distinct variants of this logic, CPL and CPL*, are presented ... 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

An inequality for Kruskal-Macaulay functionsSep 21 2008Apr 25 2009Given integers $k\geq1$ and $n\geq0$, there is a unique way of writing $n$ as $n=\binom{n_{k}}{k}+\binom{n_{k-1}}{k-1}+...+\binom{n_{1}}{1}$ so that $0\leq n_{1}<...<n_{k-1}<n_{k}$. Using this representation, the \emph{Kruskal-Macaulay function of}$n$ ... More

Pure threshold strategies for a two-node tandem network under partial informationSep 30 2015Nov 03 2015In a two node tandem network, customers decide to join or balk by maximizing a given profit function whose costs are proportional to the sojourn time they spend at each queue. Assuming that their choices are taken without knowing the complete state of ... More