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Phase Transitions for quantum Ising model with competing XY -interactions on a Cayley treeFeb 08 2019The main aim of the present paper is to establish the existence of a phase transition for the quantum Ising model with competing XY interactions within the quantum Markov chain (QMC) scheme. In this scheme, we employ the $C^*$-algebraic approach to the ... More

A new class of rank one transformations with singular spectrumApr 18 2007We introduce a new tool to study the spectral type of rank one transformations using the method of central limit theorem for trigonometric sums. We get some new applications.

The Rudin-Shapiro polynomials and The Fekete polynomials are not $L^α$-flatMar 13 2016Apr 15 2016We establish that the Rudin-Shapiro polynomials are not $L^\alpha$-flat, for any $\alpha \geq 0$. We further prove that the "truncated" Rudin-Shapiro sequence cannot generate a sequence of $L^\alpha$-flat polynomials, for any $\alpha \geq 0$. In the appendix, ... More

On the Erdös flat polynomials problem, Chowla conjecture and Riemann HypothesisSep 12 2016Jan 11 2017There are no square $L^2$-flat sequences of polynomials of the type $$\frac{1}{\sqrt q}( \epsilon_0 + \epsilon_1z + \epsilon_2z^2 + \cdots + \epsilon_{q-2}z^{q-2} +\epsilon_q z^{q-1}),$$ where for each $j,~~ 0 \leq j\leq q-1,~\epsilon_j = \pm 1$. It follows ... More

On the Erdös flat polynomials problemSep 12 2016There are no square $L^2$-flat sequences of polynomials of the type $$\frac{1}{\sqrt q}(\epsilon_0 + \epsilon_1z + \epsilon_2z^2 + \cdots + \epsilon_{q-2}z^{q-2} +\epsilon_q z^{q-1}),$$ where for each $j,~~ 0 \leq j\leq q-1,~\epsilon_j = \pm 1$. It follows ... More

Ergodic Banach problem, flat polynomials and Mahler's measures with combinatoricsAug 26 2015Jan 06 2016We construct a sequence of polynomials that are flat in the almost everywhere sense. The construction is done by appealing to the nice combinatorial properties of the Singer's sets and Sidon sets. As a consequence, we get a positive answer to Littlewood's ... More

Oscillating sequences, Gowers norms and Sarnak's conjectureApr 18 2017Oct 05 2017It is shown that there is an oscillating sequence of higher order which is not orthogonal to the class of dynamical flow with topological entropy zero. We further establish that any oscillating sequence of order $d$ is orthogonal to any $d$-nilsequence ... More

On the spectral type of some class of rank one flowsMay 24 2012Aug 10 2012It is shown that a certain class of Riesz product type measure on $\R$ is singular. This proves the singularity of the spectral types of some class of rank one flows. Our method is based on the extension of the Central Limit Theorem approach to the real ... More

On the spectrum of $α$-rigid mapsFeb 16 2009Apr 02 2009It is shown that there exists an $\alpha$-rigid transformation with $\alpha$ less or equal to $\frac12$ whose spectrum has Lebesgue component. This answers the question raised by Klemes and Reinhold in \cite{Klemes-Reinhold}. We exhibit also a large class ... More

A simple proof of Bourgain's theorem on the singularity of the spectrum of Ornstein's mapsAug 26 2015Aug 30 2015We give a simple proof of Bourgain's theorem on the singularity of Ornstein's maps.

On Veech's proof of Sarnak's theorem on the Möbius flowNov 15 2017Jan 28 2019We present Veech's proof of Sarnak's theorem on the M\"{o}bius flow which say that there is a unique admissible measure on the M\"{o}bius flow. As a consequence, we obtain that Sarnak's conjecture is equivalent to Chowla conjecture with the help of Tao's ... More

Generalized Riesz Products on the Bohr compactification of $\R$Jun 03 2012Dec 19 2014We study a class of generalized Riesz products connected to the spectral type of some class of rank one flows on $\R$. Applying a Central Limit Theorem of Kac, we exhibit a large class of singular generalized Riesz products on the Bohr compactification ... More

Ergodic Banach problem on simple Lebesgue spectrum and flat polynomialsAug 26 2015Aug 07 2018We exhibit a sequence of flat polynomials with coefficients $0,1$. We thus get that there exist a sequences of Newman polynomials that are $L^\alpha$-flat, $0 \leq \alpha <2$. This settles an old question of Littlewood. In the opposite direction, we prove ... More

On the homogeneous ergodic bilinear averages with Möbius and liouville weightsJun 15 2017Aug 15 2018It is shown that the homogeneous ergodic bilinear averages with M\"{o}bius or Liouville weight converge almost surely to zero, that is, if $T$ is a map acting on a probability space $(X,\mathcal{A},\mu)$, and $a,b \in \mathbb{Z}$, then for any $f,g \in ... More

The PAH hypothesis after 25 yearsNov 15 2011The infrared spectra of many galactic and extragalactic objects are dominated by emission features at 3.3, 6.2, 7.7, 8.6 and 11.2 \mu m. The carriers of these features remained a mystery for almost a decade, hence the bands were dubbed the unidentified ... More

D-branes on Noncommutative OrbifoldsMay 19 2001We study tachyon condensation on noncommutative toric orbifolds with a $Z_2$ discrete group and explore the various kins of brane bound states arising in the case of irrational values of the B-field. We show that $Z_$ symmetry of the orbifolds incorporates ... More

Solitons on compact and noncompact spaces in large noncommutativityDec 28 2000Jan 06 2001We study solutions at the minima of scalar field potentials for Moyal spaces and torii in the large non-commutativity and interprete these solitons in terms of non-BPS D-branes of string theory. We derive a mass spectrum formula linking different D-branes ... More

Spin-Magnetic Field Interaction and Realization of Fractional SupersymmetryAug 06 2001The fractional supersymmetry in the case of the non-relativistic motion of one anyon with fractional spin is realized. Thus the associated Hamiltonian is discussed.

Disjointness of the Möbius Transformation and Möbius FunctionNov 29 2017Apr 05 2018We study the distribution of the sequence of elements of the discrete dynamical system generated by the M\"obius transformation $x \mapsto (ax + b)/(cx + d)$ over a finite field of $p$ elements. Motivated by a recent conjecture of P. Sarnak, we obtain ... More

Approximate transitivity property and Lebesgue spectrumMar 03 2009Mar 08 2009Exploiting a spectral criterion for a system not to be AT we give some new examples of zero entropy systems without the AT property. Our examples include those with finite spectral multiplicity -- in particular we show that the system arising from the ... More

A note on actions with finite orbits on dendritesFeb 27 2019Apr 12 2019It is shown that the restriction of the action of any group with finite orbit on the minimal sets of dendrites is equicontinuous. Consequently, we obtain that the action of any amenable group and Thompson group on dendrite restricted on minimal sets is ... More

Corings over rings with local unitsDec 30 2005Apr 27 2009We show that the category of corings over a fixed base ring with local units is equivalent to the category of comonads in (right) unital modules whose underlying functors preserve inductive limits. Changing base rings, we prove a bi-equivalence of bicategories. ... More

On Black Hole Effective Potential in 6D/7D N=2 SupergravityMar 06 2008May 27 2008Using the harmonic superspace method and the duality between real and complex representations of hypermultiplets, we compute the explicit scalar field expression of the quaternionic metric $G_{mn}$ of the moduli space SO(1,1)x[SO(4,k)/(SO(4)xSO(k))] of ... More

Tetrahedron in F-theory CompactificationJul 15 2009Complex tetrahedral surface $\mathcal{T}$ is a non planar projective surface that is generated by four intersecting complex projective planes $CP^{2}$. In this paper, we study the family $\{\mathcal{T}_{m}\} $ of blow ups of $\mathcal{T}$ and exhibit ... More

Minimax Impulse Control Problems in Finite HorizonMay 04 2013We consider the problem of impulse control minimax in finite horizon, when cost functions $(C(t,x,\xi)>0)$. We show existence of value function of the problem. Moreover, the value function is characterized as the unique viscosity solution of an Isaacs ... More

Limit Behaviour of Sequential Empirical Measure ProcessesOct 30 2008In this paper, we obtain some uniform laws of large numbers and functional central limit theorems for sequential empirical measure processes indexed by classes of product functions satisfying appropriate Vapnik-Chervonenkis properties.

Network Routing Optimization Using Swarm IntelligenceSep 18 2012Aug 17 2015The aim of this paper is to highlight and explore a traditional problem, which is the minimum spanning tree, and finding the shortest-path in network routing, by using Swarm Intelligence. This work to be considered as an investigation topic with combination ... More

On the asymptotic normality of frequency polygons for strongly mixing spatial processesJul 26 2013This paper establishes the asymptotic normality of frequency polygons in the context of stationary strongly mixing random fields indexed by $\Z^d$. Our method allows us to consider only minimal conditions on the width bins and provides a simple criterion ... More

Efficient techniques for mining spatial databasesJun 01 2012Clustering is one of the major tasks in data mining. In the last few years, Clustering of spatial data has received a lot of research attention. Spatial databases are components of many advanced information systems like geographic information systems ... More

Cell Associations that Maximize the Average Uplink-Downlink Degrees of FreedomMay 13 2016We study the problem of associating mobile terminals to base stations in a linear interference network, with the goal of maximizing the average rate achieved over both the uplink and downlink sessions. The cell association decision is made at a centralized ... More

Parametric estimation of hidden stochastic model by contrast minimization and deconvolution: application to the Stochastic Volatility ModelFeb 12 2012Mar 14 2013We study a new parametric approach for particular hidden stochastic models such as the Stochastic Volatility model. This method is based on contrast minimization and deconvolution. After proving consistency and asymptotic normality of the estimation leading ... More

Common-Description Learning: A Framework for Learning Algorithms and Generating Subproblems from Few ExamplesMay 01 2016Current learning algorithms face many difficulties in learning simple patterns and using them to learn more complex ones. They also require more examples than humans do to learn the same pattern, assuming no prior knowledge. In this paper, a new learning ... More

Cloud-Based Topological Interference Management: A Case with No Cooperative Transmission GainMay 17 2016We study the problem of managing interference in linear networks, with backhaul constraints that admit centralized allocation of messages to transmitters through the cloud. Our setting is that of a generic channel, where no channel state information is ... More

A non-unital algebra has UUNP iff its unitization has UUNPDec 10 2015Let $A$ be a non-unital Banach algebra, S. J. Bhatt and H. V. Dedania showed that $A$ has the unique uniform norm property (UUNP) if and only if its unitization has UUNP. Here we prove this result for any non-unital algebra.

On saturated uniformly A-convex algebrasJan 07 2013Aug 11 2014Following ideas of A.C.Cochran, we give a suitable definition of a saturated uniformly A-convex algebra. In the m-convex case, such algebra is a uniform topological one.

Positive linear functionals on BP*-algebrasMay 07 2013Apr 12 2015Let A be a BP*-algebra with identity e, P_{1}(A) be the set of all positive linear functionals f on A such that f(e) = 1, and let M_{s}(A) be the set of all nonzero hermitian multiplicative linear functionals on A. We prove that M_{s}(A) is the set of ... More

Counting positive intersection points of a trinomial and a $\mathbf{T}$-nomial curves via Groethendieck's dessin d'enfantDec 17 2015We consider real polynomial systems $f=g=0$ in two variables where $f$ has $t\geq 3$ monomial terms and $g$ has $3$ monomials terms. We prove that the number of positive isolated solutions of such a system does not exceed $3\cdot 2^{t-2} - 1$. This improves ... More

The (> Half) Empty UniverseApr 02 1997Voids are the most prominent feature of the large-scale structure of the universe. Still, they have been generally ignored in quantitative analysis of it, essentially due to the lack of an objective tool to identify the voids and to quantify them. To ... More

A Mobile Management System for Reforming Subsidies Distribution in Developing CountriesApr 30 2014This paper has a specific objective of being useful for showing how the advances in mobile technologies can help for solving social and political aspects involved in the reform of subsidies in developing countries. It describes the work done to build ... More

Search for sharp neutrino features from dark matter decayJun 02 2016The discovery of a neutrino line or, more broadly, a sharp feature in neutrino data could provide a striking hint for the existence of the dark matter particle. We review here a search for sharp spectral features using neutrino data from IceCube. No significant ... More

Weighted Hardy inequality on Riemannian manifoldsApr 04 2015Nov 13 2015Let $(M,g)$ be a smooth compact Riemannian manifold of dimension $N\geq 3$ and we let $\Sigma$ to be a closed submanifold of dimension $1 \leq k \leq N-2. $ In this paper we study existence and non-existence of minimizers of Hardy inequality with weight ... More

Probabilistic pointer analysis for multithreaded programsDec 16 2011The use of pointers and data-structures based on pointers results in circular memory references that are interpreted by a vital compiler analysis, namely pointer analysis. For a pair of memory references at a program point, a typical pointer analysis ... More

Functional continuity of unital $B_{0}$-algebras with orthogonal basesJul 08 2015Mar 12 2016Let $A$ be a unital $B_{0}$-algebra with an orthogonal basis, then every multiplicative linear functional on $A$ is continuous. This gives an answer to a problem posed by Z. Sawon and Z. Wronski.

On a conjecture concerning some automatic continuity theoremsJan 12 2013Let A and B be commutative locally convex algebras with unit. A is assumed to be a uniform topological algebra. Let h be an injective homomorphism from A to B. Under additional assumptions, we characterize the continuity of the homomorphism h^(-1) / Im(h) ... More

Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray BlazarsMar 09 2016The expected level of gamma-gamma absorption in the Broad Line Region (BLR) radiation field of gamma-ray loud Flat Spectrum Radio Quasars (FSRQs)is evaluated as a function of the location of the gamma-ray emission region. This is done self-consistently ... More

Analytic structures of unitary RSOS models with integrable boundary conditionsMay 15 2018In this paper, we consider the unitary critical restricted-solid-on-solid (RSOS) lattice $\mathcal{M}(5,6)$ model with integrable boundary conditions. We introduce its commuting double row transfer matrix satisfying the universal functional relations, ... More

Solving the Course-timetabling Problem of Cairo University Using Max-SATFeb 11 2018Due to the good performance of current SAT (satisfiability) and Max-SAT (maximum ssatisfiability) solvers, many real-life optimization problems such as scheduling can be solved by encoding them into Max-SAT. In this paper we tackle the course timetabling ... More

Optimal Random Access and Random Spectrum Sensing for an Energy Harvesting Cognitive Radio with and without Primary Feedback LeveragingJan 01 2014Apr 27 2014We consider a secondary user (SU) with energy harvesting capability. We design access schemes for the SU which incorporate random spectrum sensing and random access, and which make use of the primary automatic repeat request (ARQ) feedback. We study two ... More

A la Recherche des Facteurs Déterminants de l'Intégration Internationale des Marchés Boursiers : une Analyse sur Données de PanelMay 24 2009The aim of this paper is to identify the determinants of international stock markets integration. Intuitively we selected a great number of factors linked to financial integration. Then, we developed an international asset-pricing model with time-varying ... More

The Ran-Reurings fixed point theorem without partial order: a simple proofNov 18 2014Nov 26 2014The purpose of this note is to generalize the celebrated Ran and Reurings fixed point theorem to the setting of a space with a binary relation that is only transitive (and not necessarily a partial order) and a relation-complete metric. The arguments ... More

Intersection Theorems for Closed Convex Sets and ApplicationsJan 23 2015A number of landmark existence theorems of nonlinear functional analysis follow in a simple and direct way from the basic separation of convex closed sets in finite dimension via elementary versions of the Knaster-Kuratowski-Mazurkiewicz principle - which ... More

Characterization of circuits supporting polynomial systems with the maximal number of positive solutionsMar 06 2016A polynomial system with $n$ equations in $n$ variables supported on a set $\mathcal{W}\subset\mathbb{R}^n$ of $n+2$ points has at most $n+1$ non-degenerate positive solutions. Moreover, if this bound is reached, then $\mathcal{W}$ is minimally affinely ... More

On the largest eigenvalue of Wishart matrices with identity covariance when n, p and p/n tend to infinitySep 22 2003Let X be a n*p matrix and l_1 the largest eigenvalue of the covariance matrix X^{*}*X. The "null case" where X_{i,j} are independent Normal(0,1) is of particular interest for principal component analysis. For this model, when n, p tend to infinity and ... More

On Relatively Prime Subsets and SupersetsOct 24 2009A nonempty finite set of positive integers A is relatively prime if gcd(A) = 1 and it is relatively prime to n if gcd(A [ fng) = 1. The number of nonempty subsets of A which are relatively prime to n is \Phi(A, n) and the number of such subsets of cardinality ... More

Explicit formulas and vanishing conditions for certain coefficients of Drinfeld-Goss Hecke eigenformsMay 27 2017We obtain a closed form polynomial expression for certain coefficients of Drinfeld-Goss double-cuspidal modular forms which are eigenforms for the degree one Hecke operators with power eigenvalues, and we use those formulas to prove vanishing results ... More

NC Effective Gauge Model for Multilayer FQH StatesAug 20 2002We develop an effective field model for describing FQH states with rational filling factors that are not of Laughlin type. These kinds of systems, which concern single layer hierarchical states and multilayer ones, were observed experimentally; but have ... More

The Best Templates Match Technique For Example Based Machine TranslationJun 04 2014It has been proved that large scale realistic Knowledge Based Machine Translation applications require acquisition of huge knowledge about language and about the world. This knowledge is encoded in computational grammars, lexicons and domain models. Another ... More

A Lemma Based Evaluator for Semitic Language Text Summarization SystemsMar 22 2014Matching texts in highly inflected languages such as Arabic by simple stemming strategy is unlikely to perform well. In this paper, we present a strategy for automatic text matching technique for for inflectional languages, using Arabic as the test case. ... More

Keyphrase Based Arabic Summarizer (KPAS)Jun 23 2012This paper describes a computationally inexpensive and efficient generic summarization algorithm for Arabic texts. The algorithm belongs to extractive summarization family, which reduces the problem into representative sentences identification and extraction ... More

A note on actions with finite orbits on dendritesFeb 27 2019It is shown that the restriction of the action of any group with finite orbit on the minimal sets of dendrites is equicontinuous. Consequently, we obtain that the action of any amenable group and Thompson group on dendrite restricted on minimal sets is ... More

A cubic nonconventional ergodic average with multiplicative or Mangoldt weightsJun 17 2016Nov 04 2016We show that the cubic nonconventional ergodic averages of any order with a bounded multiplicative function weight converge almost surely to zero provided that the multiplicative function satisfies a strong Daboussi-Delange condition. We further obtain ... More

Resonant final-state interactions in D^0 -> \bar{K}^{0} η, \bar{K}^{0} η' DecayOct 13 1999We have investimated the effect of the isospin 1/2, J^P = 0^+ resonant state K^*_0(1950) on the decays D^0 ->\bar{K}^{0}\eta and D^0 ->\bar{K}^0 \eta' as a function of the branching ratio sum r =Br(K^*_0(1950)->\bar{K}^0\eta)+ Br(K^*_0(1950)->\bar{K}^0 ... More

Helicity and partial wave amplitude analysis of D -> K^* ρdecayOct 14 1999We have carried out an analysis of helicity and partial-wave amplitudes for the process D -> K^* \rho in the factorization approximation using several models for the form factors. All the models, with the exception of one, generate partial-wave amplitudes ... More

Multi-Topic Multi-Document SummarizerJan 03 2014Current multi-document summarization systems can successfully extract summary sentences, however with many limitations including: low coverage, inaccurate extraction to important sentences, redundancy and poor coherence among the selected sentences. The ... More

An Accurate Arabic Root-Based Lemmatizer for Information Retrieval PurposesMar 15 2012In spite of its robust syntax, semantic cohesion, and less ambiguity, lemma level analysis and generation does not yet focused in Arabic NLP literatures. In the current research, we propose the first non-statistical accurate Arabic lemmatizer algorithm ... More

A cubic nonconventional ergodic average with Möbius and Liouville weightApr 03 2015May 16 2015It is shown that the cubic nonconventional ergodic average of order 2 with M\"obius and Liouville weight converge almost surely to zero. As a consequence, we obtain that the Ces\`aro mean of the self-correlations and some moving average of the self-correlations ... More

A Blockchain Example for Cooperative Interference ManagementAug 04 2018We present an example where a distributed coordinated protocol supported by a blockchain-enabled monetary mechanism leads to achieving optimal information theoretic degrees of freedom gains. The considered setting is that of a linear interference network, ... More

A cubic nonconventional ergodic average with multiplicative or Mangoldt weightsJun 17 2016We show that the cubic nonconventional ergodic averages of any order with a bounded multiplicative function weight converge almost surely to zero provided that the multiplicative function satisfies a strong Daboussi-Delange condition. We further obtain ... More

Graded q-pseudo-differential Operators and Supersymmetric AlgebrasNov 08 2000Dec 06 2000We give a supersymmetric generalization of the sine algebra and the quantum algebra $U_{t}(sl(2))$. Making use of the $q$-pseudo-differential operators graded with a fermionic algebra, we obtain a supersymmetric extension of sine algebra. With this scheme ... More

A Combinatorial Interpretation of the LDU Decomposition of Totally Positive MatricesOct 26 2015We study the combinatorial description of the LDU decomposition of totally positive matrices. We give a description of the lower triangular L, the diagonal D, and the upper triangular U matrices of the LDU decomposition of totally positive matrices in ... More

On the pointwise convergence of the cubic average with multiplicative or von Mangoldt weightsJul 02 2018It is shown that the cubic nonconventional ergodic averages of any order with a bounded aperiodic multiplicative function or von Mangoldt weights converge almost surely.

Topological SL(2) Gauge Theory on ConifoldJan 04 2006Using a two component $SL(2) $ isospinor formalism, we study the link between conifold $T^{\ast}\mathbb{S}^{3}$ and q-deformed non commutative holomorphic geometry in complex four dimensions. Then, thinking about conifold as a projective complex three ... More

Hyperbolic Invariance in Type II SuperstringsFeb 20 2005We first review aspects of Kac Moody indefinite algebras with particular focus on their hyperbolic subset. Then we present two field theoretical systems where these structures appear as symmetries. The first deals with complete classification of $\mathcal{N}=2$ ... More

Mutation Symmetries in BPS Quiver Theories: Building the BPS SpectraApr 02 2012Aug 14 2012We study the basic features of BPS quiver mutations in 4D $\mathcal{N}=2$ supersymmetric quantum field theory with $G=ADE$ gauge symmetries.\ We show, for these gauge symmetries, that there is an isotropy group $\mathcal{G}_{Mut}^{G}$ associated to a ... More

Dead code elimination based pointer analysis for multithreaded programsDec 20 2012This paper presents a new approach for optimizing multitheaded programs with pointer constructs. The approach has applications in the area of certified code (proof-carrying code) where a justification or a proof for the correctness of each optimization ... More

Critical density of a soliton gasDec 08 2015Feb 15 2016We quantify the notion of a dense soliton gas by establishing an upper bound for the integrated density of states of the quantum-mechanical Schr\"odinger operator associated with the KdV soliton gas dynamics. As a by-product of our derivation we find ... More

On uniform topological algebrasJan 20 2013Oct 18 2013The uniform norm on a uniform normed Q-algebra is the only uniform Q-algebra norm on it. The uniform norm on a regular uniform normed Q-algebra with unit is the only uniform norm on it. Let A be a uniform topological algebra whose spectrum M (A) is equicontinuous, ... More

Program Optimization Based Pointer Analysis and Live Stack-Heap AnalysisApr 04 2011In this paper, we present type systems for flow-sensitive pointer analysis, live stack-heap (variables) analysis, and program optimization. The type system for live stack-heap analysis is an enrichment of that for pointer analysis; the enrichment has ... More

On geometrically transitive Hopf algebroidsAug 24 2015Oct 26 2015This paper contributes in the characterization of a certain class of commutative Hopf algebroids. It is shown that a given commutative flat Hopf algebroid with a non trivial base ring and a non empty characters groupoid, is geometrically transitive if ... More

Hospitality Students' Perceptions towards Working in Hotels: a case study of the faculty of tourism and hotels in Alexandria UniversityJul 22 2018The tourism and hospitality industry worldwide has been confronted with the problem of attracting and retaining quality employees. If today's students are to become the effective practitioners of tomorrow, it is fundamental to understand their perceptions ... More

Short proofs for $q$-Raabe formula and integrals for Jacobi theta functionsSep 22 2016We shall answer a question of Mez\H{o} on the $q$-analogue of the Raabe's integral formula for $0<q<1$ and we shall evaluate an integral involving the first theta function. Moreover, we will reproduce short proofs for some identities of Mez\H{o}.

On Conformal Paneitz Curvature Equations in Higher Dimensional SpheresDec 06 2004We study the problem of prescribing the Paneitz curvature on higher dimensional spheres. Particular attention is paid to the blow-up points, i.e. the critical points at infinity of the corresponding variational problem. Using topological tools and a careful ... More

Boundary null-controllability of two coupled parabolic equations : simultaneous condensation of eigenvalues and eigenfunctionsFeb 12 2019Let the matrix operator L = D$\partial$xx + q(x)A0, with D = diag(1, $\nu$), $\nu$ = 1, q $\in$ L $\infty$ (0, $\pi$), and A0 is a Jordan block of order 1. We analyze the boundary null controllability for system yt -- Ly = 0. When v \notin Q * + and q(x) ... More

Optimal Spectrum Access for Cognitive RadiosAug 22 2012Mar 24 2013In this paper, we investigate a time-slotted cognitive setting with buffered primary and secondary users. In order to alleviate the negative effects of misdetection and false alarm probabilities, a novel design of spectrum access mechanism is proposed. ... More

Cognitive Access Protocol for Alleviating Sensing Errors in Cognitive Multiple-Access SystemsOct 29 2016This letter studies a time-slotted multiple-access system with a primary user (PU) and a secondary user (SU) sharing the same channel resource. We propose a novel secondary access protocol which alleviates sensing errors and detects the availability of ... More

Multipliers of uniform topological algebrasAug 19 2016Jan 22 2017Let $E$ be a complete uniform topological algebra with Arens-Michael normed factors $\left(E_{\alpha}\right)_{\alpha\in\Lambda}.$ Then $M\left(E\right) \cong \varprojlim M\left(E_{\alpha}\right)$ within an algebra isomorphism $\varphi$. If each factor ... More

The spectrum of kernel random matricesJan 04 2010We place ourselves in the setting of high-dimensional statistical inference where the number of variables $p$ in a dataset of interest is of the same order of magnitude as the number of observations $n$. We consider the spectrum of certain kernel random ... More

Concentration of measure and spectra of random matrices: Applications to correlation matrices, elliptical distributions and beyondDec 10 2009We place ourselves in the setting of high-dimensional statistical inference, where the number of variables $p$ in a data set of interest is of the same order of magnitude as the number of observations $n$. More formally, we study the asymptotic properties ... More

Nonparametric regression estimation for random fields in a fixed-designFeb 04 2005We investigate the nonparametric estimation for regression in a fixed-design setting when the errors are given by a field of dependent random variables. Sufficient conditions for kernel estimators to converge uniformly are obtained. These estimators can ... More

Extended Distributive Law: Co-wreath over co-ringsDec 28 2006A basic theory of cowreath or extended distributive laws in the bicategory of unital bimodules, is deciphered. Precisely, we give in terms of tensor product over a scalar base ring, a simplest and equivalent definition for cowreath over coring and for ... More

A gamma function in two variablesMay 09 2013We introduce a gamma function $\Ga(x,z)$ in two complex variables which extends the classical gamma function $\Ga(z)$ in the sense that $\lim_{x\to 1}\Ga(x,z)=\Ga(z)$. We will show that many properties which $\Ga(z)$ enjoys extend in a natural way to ... More

On the pointwise convergence of multiple ergodic averagesJun 10 2014Apr 26 2017It is shown that there exist a subsequence for which the multiple ergodic averages of commuting invertible measure preserving transformations of a Lebesgue probability space converge almost everywhere provided that the maps are weakly mixing with an ergodic ... More

Graded Brauer groups of a groupoid with involutionFeb 09 2012Feb 23 2014We define a group $RBr(\mathcal{G})$ containing, in a sense, the graded complex and orthogonal Brauer groups of a locally compact groupoid $\mathcal{G}$ equipped with an involution. When the involution is trivial, we show that the new group naturally ... More

On groupoids with involutions and their cohomologyFeb 01 2012Feb 06 2012We extend the definitions and main properties of graded extensions to the category of locally compact groupoids endowed with involutions. We introduce Real \v{C}ech cohomology, which is an equivariant-like cohomology theory suitable for the context of ... More

Crossed extensions and equivalences of topological 2-groupoidsFeb 06 2018We provide concrete models for generalized morphisms and Morita equivalences of topological 2-groupoids by introducing the notions of crossings and crossed extensions of groupoid crossed modules. A systematic study of these objects is elaborated and an ... More

On the Construction of Generalized Grassmann Coherent StatesNov 07 2005A generalized definition of a deformation of the fermionic oscillator (k-fermionic oscillators) is proposed. Two prescriptions for the construction of generalized Grassmann coherent states for this kind of oscillators are derived. The two prescriptions ... More

The homogenized equation of a heterogenous Reaction-Diffusion model involving pulsating traveling frontsJul 28 2009Mar 29 2011The goal of this paper is to find the homogenized equation of a heterogenous Fisher-KPP model in a periodic medium. The solutions of this model are pulsating travelling fronts whose \emph{speeds} are superior to a parametric minimal speed $c^*_L$. We ... More

Single Blow up Solutions for a Slightly Subcritical Biharmonic EquationDec 06 2004In this paper, we consider a biharmonic equation under the Navier boundary condition and with a nearly critical exponent $(P_\epsilon): \Delta^2u=u^{9-\epsilon}, u>0$ in $\Omega$ and $u=\Delta u=0$ on $\partial\Omega$, where $\Omega$ is a smooth bounded ... More

Quark Flavor Physics ReviewMar 20 2014I review the status of lattice-QCD calculations relevant to quark flavor physics. The recent availability of physical-mass ensembles with large physical volumes generated by a growing number of lattice collaborations is an exciting development and I discuss ... More

A "milder" version of Calderón's inverse problem for anisotropic conductivities and partial dataJan 29 2015Apr 13 2016Given a general symmetric elliptic operator $$ L\_{a} := \sum\_{k,,j=1}^d \p\_k (a\_{kj} \p\_j) + \sum\_{k=1}^d a\_k \p\_k - \p\_k(\overline{a\_k} .) + a\_0$$we define the associated Dirichlet-to-Neumann (D-t-N) operator with partial data, i.e., data ... More