January 2005 arXiv papers — page 11

F. Bocchino

The detection of a soft thermal X-ray component in the spectrum of a bright knot in the halo of the plerion G21.5-0.9 is reported. Using a collisional ionization equilibrium model for an hot optically thin plasma, a temperature $kT=0.12-0.24$ kev, a mass of 0.3--1.0 M$_\odot$ and a density of 1.6-6 cm$^{-3}$ is derived. The spectral analysis suggests a possi

M. Revnivtsev, S. Fabrika, P. Abolmasov, K. Postnov

We present broad band power spectra of variations of SS433 in radio, optical and X-ray spectral bands. We show that at frequencies lower than 1e-5 Hz the source demonstrates the same variability pattern in all these bands. The broad band power spectrum can be fitted by one power law down to frequencies ~1e-7 Hz with flattening afterwards. Such a flattening m

Chris P. Pearson

Galaxy source counts that simultaneously fit the deep mid-infrared surveys at 24 microns and 15 microns made by the Spitzer Space Telescope and the Infrared Space Observatory (ISO) respectively are presented for two phenomenological models. The models are based on starburst and luminous infrared galaxy dominated populations. Both models produce excellent fit

H. E. S. S. Collaboration, :, F. Aharonian

The region around PSR B1706-44 has been observed with the H.E.S.S. imaging atmospheric Cherenkov telescopes in 2003. No evidence for gamma-ray emission in the TeV range was found at the pulsar position or at the radio arc which corresponds to the supernova remnant G 343.1-2.3. The 99% confidence level flux upper limit at the pulsar position is Ful(E > 350GeV

Annette Ferguson, Rachel Johnson, Daniel Faria, Mike Irwin

We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Te

Rafal M. Nowakowski

We consider evolution of an unstable acoustic mode interacting with an ensemble of stable g-modes. We show that the static multimode solution does not exist. We then find the condition for the stability of the statistical equilibrium. Performing numerical integration of amplitude equations for a simplified system we find that the acoustic mode amplitude exhi

G. Covone, M. Sereno, R. de Ritis

We evaluate the effect of small scale inhomogeneities on large scale observations within the statistics of gravitationally lensed quasars. At this aim, we consider a cosmological model whose large scale properties (dynamics, matter distribution) are the same as in Friedmann-Lemaitre models, but whose matter distribution is locally inhomogeneous. We use the w

F. La Barbera, G. Covone, G. Busarello, M. Capaccioli

We study the Photometric Plane (PHP), namely the relation between the effective radius re, the mean surface brightness within that radius <mi>e, and the Sersic index n, in optical (R and I) and near-infrared (K) bands for a large sample of early-type galaxies (ETGs) in the rich cluster MS1008-1224 at z=0.306. The PHP relation has an intrinsic dispersion of ~

S. E. Shaw, N. Mowlavi, J. Rodriguez, P. Ubertini

We report the discovery of a high-energy transient with the IBIS/ISGRI detector on board the INTEGRAL observatory. The source, namely IGR J00291+5934, was first detected on 2nd December 2004 in the routine monitoring of the IBIS/ISGRI 20--60 keV images. The observations were conducted during Galactic Plane Scans, which are a key part of the INTEGRAL Core Pro

M. J. Coe

This work investigates the possible supernova kick velocities imposed on HMXB systems in the Small Magellanic Cloud. Comparisons are made between the location of such systems and the locations of young, stellar clusters on the premise that these may represent the birthplace of many of these systems. Measurements of the separation of clusters and HMXBs,and an

M. Kregel, P. C. van der Kruit, K. C. Freeman

In earlier papers in this series we determined the intrinsic stellar disc kinematics of fifteen intermediate to late type edge-on spiral galaxies using a dynamical modeling technique. From the photometry we find that intrinsically more flattened discs tend to have a lower face-on central surface brightness and a larger dynamica mass-to-light ratio. This obse

Motokazu Takizawa

Clusters of galaxies form through major merger and/or absorption of smaller groups. In fact, some characteristic structures such as cold fronts, which are likely relevant to moving substructures, are found by {\it Chandra}. It is expected that moving substructures generate turbulence in the intracluster medium (ICM). Such turbulence probably plays a crucial

Young-Wook Lee, Seok-Joo Joo, Sang-Il Han, Chul Chung

Recent observations for the color-magnitude diagrams (CMDs) of the massive globular cluster Omega Centauri have shown that it has a striking double main sequence (MS), with a minority population of bluer and fainter MS well separated from a majority population of MS stars. Here we confirm, with the most up-to-date Y2 isochrones, that this special feature can

Yukari Matsumoto, Kazuo Makishima, Jun&#39;ichi Kotoku, Masato Yoshimori

Gamma-ray emitting solar flares observed with Yohkoh were analyzed from a statistical viewpoint. The four-band hard X-ray (15--95 keV) photometric data, taken with the Hard X-ray Telescope onboard Yohkoh, were utilized in combination with the spectro-photometric gamma-ray (0.2--30 MeV) data obtained with the Gamma-Ray Spectrometer. The GOES class was also in

L. L. Kiss, T. R. Bedding

We investigate blending, binarity and photometric biases in crowded-field CCD imaging. For this, we consider random blend losses, which correspond to the total number of stars left undetected in unresolved blends. We present a simple formula to estimate blend losses, which can be converted to apparent magnitude biases using the luminosity function of the ana

Warrick A. Lawson, Lisa A. Crause

We have conducted a photometric study of late-type members of the TW Hydrae association (TWA) and measured the rotation periods for 16 stars in 12 systems. For TWA stars listed by Webb et al. and Sterzik et al. (TWA 1-13; led by TW Hya = TWA 1) we find a median period of 4.7 d. However, for stars that we measured in the TWA 14-19 group identified by Zuckerma

Maria Beltran, Juan Garcia-Bellido, Julien Lesgourgues, Andrew R Liddle

Present cosmological data are well explained assuming purely adiabatic perturbations, but an admixture of isocurvature perturbations is also permitted. We use a Bayesian framework to compare the performance of cosmological models including isocurvature modes with the purely adiabatic case; this framework automatically and consistently penalizes models which

Carl H. Gibson

The first turbulent combustion arises in a hot big bang cosmological model Gibson (2004) where nonlinear exothermic turbulence permitted by quantum mechanics, general relativity, multidimensional superstring theory, and fluid mechanics cascades from Planck to strong force freeze out scales with gravity balancing turbulent inertial-vortex forces. Interactions

C. -M. Chen, G. V. Kraniotis, V. E. Mayes, D. V. Nanopoulos

We construct an N=1 supersymmetric three-family flipped SU(5) model from type IIA orientifolds on $T^6/(\Z_2\times \Z_2)$ with D6-branes intersecting at general angles. The spectrum contains a complete grand unified and electroweak Higgs sector. In addition, it contains extra exotic matter both in bi-fundamental and vector-like representations as well as two

Pisin Chen, Keshav Dasgupta, K. Narayan, Marina Shmakova

In this paper we study various cosmological solutions for a D3/D7 system directly from M-theory with fluxes and M2-branes. In M-theory, these solutions exist only if we incorporate higher derivative corrections from the curvatures as well as G-fluxes. We take these corrections into account and study a number of toy cosmologies, including one with a novel bac

E. V. Blagov, G. L. Klimchitskaya, V. M. Mostepanenko

The Lifshitz theory of the van der Waals force is extended for the case of an atom (molecule) interacting with a plane surface of an uniaxial crystal or with a long solid cylinder or cylindrical shell made of isotropic material or uniaxial crystal. For a microparticle near a semispace or flat plate made of an uniaxial crystal the exact expressions for the fr

S. A. Paston, E. V. Prokhvatilov, V. A. Franke

With the aim of a further investigation of the nonperturbative Hamiltonian approach in gauge field theories, the mass spectrum of QED-2 is calculated numerically by using the corrected Hamiltonian that was constructed previously for this theory on the light front. The calculations are performed for a wide range of the ratio of the fermion mass to the fermion

Ting Gao, Feng-Li Yan, Zhi-Xi Wang

Two schemes for quantum secure conditional direct communication are proposed, where a set of EPR pairs of maximally entangled particles in Bell states, initially made by the supervisor Charlie, but shared by the sender Alice and the receiver Bob, functions as quantum information channels for faithful transmission. After insuring the security of the quantum c

J. Maurice Rojas

Suppose X is the complex zero set of a finite collection of polynomials in Z[x_1,...,x_n]. We show that deciding whether X contains a point all of whose coordinates are d_th roots of unity can be done within NP^NP (relative to the sparse encoding), under a plausible assumption on primes in arithmetic progression. In particular, our hypothesis can still hold

Che-Ming Li, Y. -N. Chen, C. -W. Luo, Jin-Yuan Hsieh

A study on the cause of the multi-particle entanglement is presented in this work. We investigate how dot-like single quantum well excitons, which are independently coupled through a single microcavity mode, evolve into maximally entangled state as a series of conditional measurements are taken on the cavity field state. We first show how cavity photon affec

Tianxing Ma, Shiping Feng

Within the t-t&#39;-J model, the charge asymmetry in superconductivity of hole- and electron-doped cuprates is studied based on the kinetic energy driven superconducting mechanism. It is shown that superconductivity appears over a narrow range of doping in electron-doped cuprates, and the superconducting transition temperature displays the same kind of the d

Antonio Ribeiro, Luis Matias, Rui Taborda

Soft or Deformable Plate Tectonics in the sphere must follow geometric rules inferred from the orthographic projection. An analytic equivalent of this geometry can be derived by the application of Potential Field Methods in the case of Atlantic type oceans. Laplace equation must be obeyed by the velocity field between the ridge and the passive margin if we n

Bruce D. Scott

The details of fluctuation free energy conservation in the gyrofluid model are examined. The polarisation equation relates ExB flow and eddy energy to combinations of the potential and the density and perpendicular temperature. These determine the combinations which must appear under derivatives in the moment equations so that not only thermal free energy bu

Angela Bonaccorso

The INFN (Italian National Institute for Nuclear Physics) has approved a national theoretical network on &#34;Structure and Reactions with Exotic Nuclei&#34;. The project involves the INFN branches of Laboratorio Nazionale del Sud, Padova and Pisa. The aim of the project is to start coordinating and to homogenize the research already performed in Italy in th

B. Hong et al

We present transverse momentum and rapidity spectra of charged pions in central Ru + Ru collisions at 400$A$ and 1528$A$ MeV. The data exhibit enhanced production at low transverse momenta compared to the expectations from the thermal model that includes the decay of $Δ(1232)$-resonances and thermal pions. Modification of the $Δ$-spectral function and the Co

F. Toschi, L. Biferale, G. Boffetta, A. Celani

We report recent results from a high resolution numerical study of fluid particles transported by a fully developed turbulent flow. Single particle trajectories were followed for a time range spanning more than three decades, from less than a tenth of the Kolmogorov time-scale up to one large-eddy turnover time. We present some results concerning acceleratio

Alexander Beilinson, Vladimir Drinfeld

This article is an elementary introduction to opers without new results. We hope it can be useful for students.

Pietro Di Giuseppe

The classification, by topological conjugacy, of invertible holomorphic germs $f:(\mathbb{C}^n,0)\to (\mathbb{C}^n,0)$, with $λ_1,...,λ_n$ eigenvalues of $df_0$, and $|λ_i|\neq 1$ for $i=2,...,n$ while $λ_1$ is a root of the unity, is given, in the suitable hypothesis of ``quasi-absence&#39;&#39; of resonances.

Vassily Olegovich Manturov

We prove that a virtual link diagrams satisfying two conditions on the Khovanov homology is minimal, that is, there is no virtual diagram representing the same link with smaller number of crossings. This approach works for both classical and virtual links

Mitsuhiro Miyazaki

Let $K$ be a field, $D$ a finite distributive lattice and $P$ the set of all join-irreducible elements of $D$. We show that if $\{y\in P\mid y\geq x\}$ is pure for any $x\in P$, then the Hibi ring $\RRRRR_K(D)$ is level. Using this result and the argument of sagbi basis theory, we show that the homogeneous coordinate rings of Schubert subvarieties of Grassma

F. Hiai, D. Petz

We give a new proof of the free transportation cost inequality for measures on the circle following M. Ledoux&#39;s idea.

Lewis Bowen

We prove the following: 1. Let epsilon>0 and let S_1,S_2 be two closed hyperbolic surfaces. Then there exists locally-isometric covers S&#39;_i of S_i (for i=1,2) such that there is a (1+ε) bi-Lipschitz homeomorphism between S&#39;_1 and S&#39;_2 and both covers S&#39;_i have bounded injectivity radius. 2. Let M be a closed hyperbolic 3-manifold. Then there

Daniel Matei, Alexander I. Suciu

We present a method for computing the number of epimorphisms from a finitely-presented group G to a finite solvable group Γ, which generalizes a formula of Gäschutz. Key to this approach are the degree 1 and 2 cohomology groups of G, with certain twisted coefficients. As an application, we count low-index subgroups of G. We also investigate the finite solvab

Harry J. Lipkin

The $Θ^+$ Pentaquark is a Very narrow $Γ\approx 1$ MeV KN Resonance. Why do some experiments see it and others do not? The lowest quark configuration that can describe it is exotic $uudd \bar s$. Why have no exotics been seen before? Is this the beginning of a new spectroscopy? Can it help toteach us about How QCD makes hadrons from quarks and gluons?

Atmospheric Neutrino Experiments Working Group

Both the first evidence and the first discoveries of neutrino flavor transformation have come from experiments which use neutrino beams provided by Nature. These discoveries were remarkable not only because they were unexpected--they were discoveries in the purest sense--but that they were made initially by experiments whose primary goals were aimed at other

Erhan Bayraktar, Li Chen, H. Vincent Poor

In this paper consistency problems for multi-factor jump-diffusion models, where the jump parts follow multivariate point processes are examined. First the gap between jump-diffusion models and generalized Heath-Jarrow-Morton (HJM) models is bridged. By applying the drift condition for a generalized arbitrage-free HJM model, the consistency condition for jum

T. Feil, H. -P. Tranitz, M. Reinwald, W. Wegscheider

The fundamental condition for operating a superlattice (SL) as a Bloch oscillator is a homogeneous electric field alignment under large applied bias. This can be done by combining the nonlinear miniband transport channel with a parallel shunt channel, connected through lateral transport. We report here about the first realization of such a SL-shunt system. W

K. Malarz, K. Kulakowski

We present the distance matrix evolution for different types of networks: exponential, scale-free and classical random ones. Statistical properties of these matrices are discussed as well as topological features of the networks. Numerical data on the degree and distance distributions are compared with theoretical predictions.

Gregg Lois, Anaël Lemaître, Jean M. Carlson

We numerically and theoretically study macroscopic properties of dense, sheared granular materials. In this process we first introduce an invariance in Newton&#39;s equations, explain how it leads to Bagnold&#39;s scaling, and discuss how it relates to the dynamics of granular temperature. Next we implement numerical simulations of granular materials in two

S. Hubrig, P. North, T. Szeifert

We rediscuss the evolutionary state of upper main sequence magnetic stars using a sample of Ap and Bp stars with accurate Hipparcos parallaxes and definitely determined longitudinal magnetic fields. FORS1 at the VLT in spectropolarimetric mode has been used to carry out a systematic search for magnetic fields in chemically peculiar stars whose magnetic field

S. Hubrig, T. Szeifert, P. North, M. Schoeller

We present the results of a magnetic survey with FORS1 in polarimetric mode of a sample of B and Herbig Ae stars with previously undetected magnetic fields. For the first time a mean longitudinal magnetic field at a level higher than 3 sigma has been detected in one normal B star, two HgMn stars, one PGa star and four SPB stars. The observations of the three

R. Nesci, S. Sclavi, E. Massaro

We investigate the nature of the BL Lac candidates in the northern part of the 2BL sample (\cite{Londish02}) searching for optical variability by means of $R_C$ band photometry with the Asiago 1.8 and Loiano 1.5 meter telescopes during years 2002, 2003 and 2004. We also made aperture photometry of the candidates on the plates available on the web from the Pa

Dan Maoz

Measurements of SN rates in different environments and redshifts can shed light on the nature of SN-Ia progenitors, star formation history, and chemical enrichment history. I summarize some recent work by our group in this area, and discuss the implications. The current evidence favors production of most of the iron in the ICM (and perhaps everywhere) by cor

Dan Maoz

In the pre-WMAP, pre-Supernova-Ia-Hubble-diagram era, quasar lensing statistics stubbornly indicated low values of Omega_Lambda. In contrast, a number of recent lensing statistics studies either find the data support the standard Lambda-CDM picture, or simply take the standard cosmological parameters as a given. Have the data or the analyses changed or impro

Xifan Wu, David Vanderbilt, D. R. Hamann

The methods of density-functional perturbation theory may be used to calculate various physical response properties of insulating crystals including elastic, dielectric, Born charge, and piezoelectric tensors. These and other important tensors may be defined as second derivatives of the total energy with respect to atomic-displacement, electric-field, or str

Sasha Sodin

If the Euclidean norm is strongly concentrated with respect to a measure, the average distribution of an average marginal of this measure has Gaussian asymptotics that captures tail behaviour. If the marginals of the measure have exponential moments, Gaussian asymptotics for the distribution of the average marginal implies Gaussian asymptotics for the distri

S. Boettcher, S. E. Cooke

Recently, a method has been proposed to obtain accurate predictions for low-temperature properties of lattice spin glasses that is practical even above the upper critical dimension, $d_c=6$. This method is based on the observation that bond-dilution enables the numerical treatment of larger lattices, and that the subsequent combination of such data at variou

Hiroyuki Abe, Yutaka Sakamura

We derive 5D N=1 superspace action including the radion superfield. The radion is treated as a dynamical field and identified as a solution of the equation of motion even in the presence of the radius stabilization mechanism. Our derivation is systematic and based on the superconformal formulation of 5D supergravity. We can read off the couplings of the dyna

M. P. Ulmer, C. Adami, G. Covone, F. Durret

This is a report of Chandra, XMM-Newton, HST and ARC observations of an extended X-ray source at z = 0.59. The apparent member galaxies range from spiral to elliptical and are all relatively red (i&#39;-Ks about 3). We interpret this object to be a fossil group based on the difference between the brightness of the first and second brightest cluster members i

David Chandler, Juan P. Garrahan

In recent papers, we have argued that kinetically constrained coarse grained models can be applied to understand dynamic properties of glass forming materials, and we have used this approach in various applications that appear to validate this view. In one such paper [J.P. Garrahan and D. Chandler, Proc. Nat. Acad. Sci. USA 100, 9710 (2003)], among other thi

Hsien-Chung Kao, Wo-Lung Lee, Feng-Li Lin

We calculate the angular scale of the acoustic oscillation from the BOOMERANG and WMAP data on the cosmic microwave background (CMB) to constrain the holographic dark energy model recently proposed by Li. We find that only the phantom-like holographic dark energy survives the cosmological tests. This is, however, inconsistent with the positive energy conditi

M. Samsonov

We obtain explicit formulas for the semi-classical twists deforming the coalgebraic structure of U(sl(3)) and U(sl(4)). In rank 2 and 3 the corresponding universal R-matrices quantize the boundary r-matrices of Cremmer-Gervais type defining Lie Frobenius structures on the maximal parabolic subalgebras in sl(n).

Chun-Hsien Wu, Da-Shin Lee

We employ the Schwinger-Keldysh formalism to study the nonequilibrium dynamics of the mirror with perfect reflection moving in a quantum field. Within the regime of linear response in terms of a first order expansion of the mirror&#39;s displacement, the coarse-grained effective action is obtained by integrating out quantum fields with the method of influenc

Frederic Herau

We consider the linear Fokker-Planck equation in a confining potential in space dimension $d \geq 3$. Using spectral methods, we prove bounds on the derivatives of the solution for short and long time, and give some applications.

Salah Aly, Andreas Klappenecker, Pradeep Kiran Sarvepalli

An attractive feature of BCH codes is that one can infer valuable information from their design parameters (length, size of the finite field, and designed distance), such as bounds on the minimum distance and dimension of the code. In this paper, it is shown that one can also deduce from the design parameters whether or not a primitive, narrow-sense BCH cont

Ted Theodosopoulos

This paper describes the construction of a lower bound for the tails of general random variables, using solely knowledge of their moment generating function. The tilting procedure used allows for the construction of lower bounds that are tighter and more broadly applicable than existing tail approximations.

E. Hernandez, A. Jauregui, A. Mondragon, L. Nellen

We show that when an isolated doublet of unbound states of a physical system becomes degenerate for some values of the control parameters of the system, the energy hypersurfaces representing the complex resonance energy eigenvalues as functions of the control parameters have an algebraic branch point of rank one in parameter space. Associated with this singu

John H. Carpenter, Karin A. Dahmen

Spreading of bacteria in a highly advective, disordered environment is examined. Predictions of super-diffusive spreading for a simplified reaction-diffusion equation are tested. Concentration profiles display anomalous growth and super-diffusive spreading. A perturbation analysis yields a crossover time between diffusive and super-diffusive behavior. The ti

Ilya A. Shkrob

Given the difficulty of obtaining compact analytical solutions for diffusion of interacting geminate pairs (such as electron-hole pairs generated by ionization of liquid) it is common, following the original method of Mozumder, to &#34;prescribe&#34; this diffusion. With this approach, the survival probability of the pair is represented as a product of the s

Joe Henson

This essay discusses the idea that a Theory of Everything would not be complete without a theory of consciousness as one of its parts, and the suggestion that new physics may be needed to describe consciousness. I argue that the motivations behind searching for such a theory arise as the result of misunderstandings over the use of language when talking about

G. Gonzalez

A necessary and sufficient condition for a parameter transformation that leaves invariant the energy of a one dimensional autonomous system is obtained. Using a parameter transformation the Hamilton-Jacobi equation is solved by a quadrature. An example of this approach is given.

G. Gaeta, S. Walcher

Integration of nonlinear dynamical systems is usually seen as associated to a symmetry reduction, e.g. via momentum map. In Lax integrable systems, as pointed out by Kazhdan, Kostant and Sternberg in discussing the Calogero system, one proceeds in the opposite way, enlarging the nonlinear system to a system of greater dimension. We discuss how this approach

Miloslav Znojil

The characteristic anti-linear (parity/time reversal, PT) symmetry of non-Hermitian Hamiltonians with real energies is presented as a source of two new forms of solvability of Schrödinger&#39;s bound-state problems. In detail we describe (1) their very specific semi-exact solvability (SES) and (2) their innovated variational tractability. SES technicalities

Yang Chen, Gunnar Pruessner

In this paper we present a brief description of a ladder operator formalism applied to orthogonal polynomials with discontinuous weights. The two coefficient functions, A_n(z) and B_n(z), appearing in the ladder operators satisfy the two fundamental compatibility conditions previously derived for smooth weights. If the weight is a product of an absolutely co

T. Alazard

The low Mach number limit for classical solutions to the full Navier Stokes equations is here studied. The combined effects of large temperature variations and thermal conduction are accounted. In particular we consider general initial data. The equations leads to a singular problem, depending on a small scaling parameter, whose linearized is not uniformly w

Yusuf Z. Gurtas

Positive Dehn twist products for some elements of finite order in the mapping class group of a 2-dimensional closed, compact, oriented surface $Σ_g$, which are rotations of $Σ_g$ through $2π/p$, are presented. The homeomorphism invariants of the resulting simply connected symplectic 4- manifolds are computed.

G. M. Kelly, V. Schmitt

Given a class Phi of weights, we study the following classes: Phi^+ of Phi-flat weights which are the psi for which psi-colimits commute in the base V with limits with weights in Phi; and Phi^-, dually defined, of weights psi for which psi-limits commute in the base V with colimits with weights in Phi. We show that both these classes are saturated (i.e. clos

S. I. Agafonov

It is shown that discrete analogs of z^c and log(z) have the same asymptotic behavior as their smooth counterparts. These discrete maps are described in terms of special solutions of discrete Painleve-II equations, asymptotics of these solutions providing the behaviour of discrete z^c and log(z) at infinity.

James S. Milne, Niranjan Ramachandran

We show how the Z_p(r)-cohomologies of a smooth projective algebraic variety can be obtained via its de Rham-Witt complex.

Philippe Flajolet, Stefan Gerhold, Bruno Salvy

We establish that the sequences formed by logarithms and by &#34;fractional&#34; powers of integers, as well as the sequence of prime numbers, are non-holonomic, thereby answering three open problems of Gerhold [Electronic Journal of Combinatorics 11 (2004), R87]. Our proofs depend on basic complex analysis, namely a conjunction of the Structure Theorem for

Friedrich Wehrung

We prove the following result: Let K be a lattice, let D be a distributive lattice with zero, and let $ϕ$: Con K $\to$ D be a {&#8744;, 0}-homomorphism, where Conc K denotes the {&#8744;, 0}-semilattice of all &#64257;nitely generated congruences of K. Then there are a lattice L, a lattice homomorphism f : K $\to$ L, and an isomorphism $\ga$: Conc L $\to$ D

Jiri Tuma, Friedrich Wehrung

Let S be a distributive {&#8744;, 0}-semilattice. In a previous paper, the second author proved the following result: Suppose that S is a lattice. Let K be a lattice, let $ϕ$: Con K $\to$ S be a {&#8744;, 0}-homomorphism. Then $ϕ$ is, up to isomorphism, of the form Conc f, for a lattice L and a lattice homomorphism f : K $\to$ L. In the statement above, Conc

Jiri Tuma, Friedrich Wehrung

We investigate categorical and amalgamation properties of the functor Idc assigning to every partially ordered abelian group G its semilattice of compact ideals Idc G. Our main result is the following. Theorem 1. Every diagram of finite Boolean semilattices indexed by a finite dismantlable partially ordered set can be lifted, with respect to the Idc functor,

Jiri Tuma, Friedrich Wehrung

We review recent results on congruence lattices of (in&#64257;nite) lattices. We discuss results obtained with box products, as well as categorical, ring-theoretical, and topological results.

Friedrich Wehrung

For a given complete lattice L, we investigate whether L can be decomposed as a direct product of directly indecomposable lattices. We prove that this is the case if every element of L is a join of join-irreducible elements and dually, thus extending to non-algebraic lattices a result of L. Libkin. We illustrate this by various examples and counterexamples.

Friedrich Wehrung

We say that a (&#8744;,0)-semilattice S is conditionally co-Brouwerian, if (1) for all nonempty subsets X and Y of S such that X $\leq$ Y (i.e., x $\leq$ y for all (x, y) $\in$ X x Y), there exists z $\in$ S such that X $\leq$ z $\leq$ Y, and (2) for every subset Z of S and all a, b $\in$ S, if a $\leq$ b &#8744; z for all z $\in$ Z, then there exists c $\in

Friedrich Wehrung

The notion of a capped tensor product, introduced by G. Grätzer and the author, provides a convenient framework for the study of tensor products of lattices that makes it possible to extend many results from the finite case to the infinite case. In this paper, we answer several open questions about tensor products of lattices. Among the results that we obtai

George Grätzer, Harry Lakser, Friedrich Wehrung

J. Tuma proved an interesting &#34;congruence amalgamation&#34; result. We are generalizing and providing an alternate proof for it. We then provide applications of this result: --A.P. Huhn proved that every distributive algebraic lattice $D$ with at most $\aleph\_1$ compact elements can be represented as the congruence lattice of a lattice $L$. We show that

Friedrich Wehrung

We prove the following result: Theorem. Every algebraic distributive lattice D with at most $\aleph\_1$ compact elements is isomorphic to the ideal lattice of a von Neumann regular ring R. (By earlier results of the author, the $\aleph\_1$ bound is optimal.) Therefore, D is also isomorphic to the congruence lattice of a sectionally complemented modular latti

George Grätzer, Friedrich Wehrung

For a finite lattice L, let EL denote the reflexive and transitive closure of the join-dependency relation on L, defined on the set J(L) of all join-irreducible elements of L. We characterize the relations of the form EL, as follows: Theorem. Let E be a quasi-ordering on a finite set P. Then the following conditions are equivalent: (i) There exists a finite

Friedrich Wehrung, Kira Adaricheva

For a class C of finite lattices, the question arises whether any lattice in C can be embedded into some atomistic, biatomic lattice in C. We provide answers to the question above for C being, respectively, --The class of all finite lattices; --The class of all finite lower bounded lattices (solved by the first author&#39;s earlier work). --The class of all

Bassam Fayad, Anatole Katok

We present an overview and some new applications of the approximation by conjugation method introduced by Anosov and the second author more than thirty years ago \cite{AK}. Michel Herman made important contributions to the development and applications of this method beginning from the construction of minimal and uniquely ergodic diffeomorphisms jointly with

S. Shulga

C++ package {\tt BtoVVana} is aimed to extract physics parameters in decays of the scalar neutral B-meson to two vector particles in the intermediate state, and two leptons and two pseudoscalar mesons in the final state. Improved angular moments method is implemented in the package {\tt BtoVVana}: the method uses the time dependent weighting functions and ti

Farhad Meshkati, Mung Chiang, Stuart C. Schwartz, H. Vincent Poor

In this work, a non-cooperative power control game for multi-carrier CDMA systems is proposed. In the proposed game, each user needs to decide how much power to transmit over each carrier to maximize its overall utility. The utility function considered here measures the number of reliable bits transmitted per joule of energy consumed. It is shown that the us

Chih-Chun Wang, Sanjeev R. Kulkarni, H. Vincent Poor

An extension of the traditional two-armed bandit problem is considered, in which the decision maker has access to some side information before deciding which arm to pull. At each time t, before making a selection, the decision maker is able to observe a random variable X_t that provides some information on the rewards to be obtained. The focus is on finding

Eran Fishler, H. Vincent Poor

One of the features characterizing almost every multiple access (MA) communication system is the processing gain. Through the use of spreading sequences, the processing gain of Random CDMA systems (RCDMA), is devoted to both bandwidth expansion and orthogonalization of the signals transmitted by different users. Another type of multiple access system is Impu

Sinan Gezici, Mung Chiang, H. Vincent Poor, Hisashi Kobayashi

Convex relaxations of the optimal finger selection algorithm are proposed for a minimum mean square error (MMSE) Rake receiver in an impulse radio ultra-wideband system. First, the optimal finger selection problem is formulated as an integer programming problem with a non-convex objective function. Then, the objective function is approximated by a convex fun

Farn Wang

Techniques for the efficient successive under-approximation of the greatest fixpoint in TCTL formulas can be useful in fast refutation of inevitability properties and vacuity checking. We first give an integrated algorithmic framework for both under and over-approximate model-checking. We design the {\em NZF (Non-Zeno Fairness) predicate}, with a greatest fi

Farn Wang

Techniques for the efficient successive under-approximation of the greatest fixpoint in TCTL formulas can be useful in fast refutation of inevitability properties and vacuity checking. We first give an integrated algorithmic framework for both under and over-approximate model-checking. We design the {\em NZF (Non-Zeno Fairness) predicate}, with a greatest fi

Eran Fishler, H. Vincent Poor

Estimating the number of sources impinging on an array of sensors is a well known and well investigated problem. A common approach for solving this problem is to use an information theoretic criterion, such as Minimum Description Length (MDL) or the Akaike Information Criterion (AIC). The MDL estimator is known to be a consistent estimator, robust against de

Jun Ichi Fujii, Ritsuo Nakamoto, Kenjiro Yanagi

Concavity of the auxiliary function which appears in the random coding exponent as the lower bound of the quantum reliability function for general quantum states is proven for s between 0 and 1.

Erhan Bayraktar, H. Vincent Poor

In this paper an arbitrage strategy is constructed for the modified Black-Scholes model driven by fractional Brownian motion or by a time changed fractional Brownian motion, when the volatility is stochastic. This latter property allows the heavy tailedness of the log returns of the stock prices to be also accounted for in addition to the long range dependen

P. Benetatos, T. Munk, E. Frey

Recent Monte Carlo simulations of a grafted semiflexible polymer in 1+1 dimensions have revealed a pronounced bimodal structure in the probability distribution of the transverse (bending) fluctuations of the free end, when the total contour length is of the order of the persistence length [G. Lattanzi et al., Phys. Rev E 69, 021801 (2004)]. In this paper, we

R. Martonak, D. Donadio, M. Parrinello

We report results of molecular dynamics simulations of amorphous ice for pressures up to 22.5 kbar. The high-density amorphous ice (HDA) as prepared by pressure-induced amorphization of Ih ice at T=80 K is annealed to T=170 K at various pressures to allow for relaxation. Upon increase of pressure, relaxed amorphous ice undergoes a pronounced change of struct

Jae Dong Noh, Hyunggyu Park

We introduce a dynamical model of coupled directed percolation systems with two particle species. The two species $A$ and $B$ are coupled asymmetrically in that $A$ particles branch $B$ particles whereas $B$ particles prey on $A$ particles. This model may describe epidemic spreading controlled by reactive immunization agents. We study nonequilibrium phase tr