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Arxiv.org
by Warren R. Brown; Mukremin Kilic; J. J. Hermes; Carlos Allende Prieto; Scott J. Kenyon; D. E. Winget
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We have discovered a detached pair of white dwarfs (WDs) with a 12.75 min orbital period and a 1,315 km/s radial velocity amplitude. We measure the full orbital parameters of the system using its light curve, which shows ellipsoidal variations, Doppler boosting, and primary and secondary eclipses. The primary is a 0.25 Msun tidally distorted helium WD, only the second tidally distorted WD known. The unseen secondary is a 0.55 Msun carbon-oxygen WD. The two WDs will come into contact in 0.9 Myr...
Source: http://arxiv.org/abs/1107.2389v1
Arxiv.org
by Nicholas J. Wright; Michael J. Barlow; Barbara Ercolano; Thomas Rauch
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We present a 3D photoionization model of the PN NGC 6302, one of the most complex objects of its kind. Our Mocassin model is composed of an extremely dense circumstellar disk and a large pair of diffuse bipolar lobes, a combination necessary to reproduce the observed spectrum. The masses of these components gives a total nebular mass of 4.7Mo. Discrepancies between our model fit and the observations are attributed to complex density inhomogeneities in the nebula. The potential to resolve such...
Source: http://arxiv.org/abs/1107.4554v1
Arxiv.org
by Peter H. Hauschildt; E. Baron
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We discuss an implementation of our 3D radiative transfer (3DRT) framework with the OpenCL paradigm for general GPU computing. We implement the kernel for solving the 3DRT problem in Cartesian coordinates with periodic boundary conditions in the horizontal $(x,y)$ plane, including the construction of the nearest neighbor $\Lstar$ and the operator splitting step. We present the results of a small and a large test case and compare the timing of the 3DRT calculations for serial CPUs and various...
Source: http://arxiv.org/abs/1107.5719v2
Arxiv.org
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For the description of the early inflation, and acceleration expansion of the Universe, compatible with observational data, the 5D noncompact Kaluza--Klein cosmology is investigated. It is proposed that the 5D space is filled with a null perfect fluid, resulting a perfect fluid in 4D universe, plus one along the fifth dimension. By analyzing the reduced field equations for flat FRW model, we show the early inflationary behavior and current acceleration of the universe.
Source: http://arxiv.org/abs/1005.3140v2
Arxiv.org
by Xi Chen; Simon P. Ellingsen; Zhi-Qiang Shen; Anita Titmarsh; Cong-Gui Gan
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We report the results of a systematic survey for 95 GHz class I methanol masers towards a new sample of 192 massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects or EGOs) identified from the Spitzer GLIMPSE survey. The observations were made with the Australia Telescope National Facility (ATNF) Mopra 22-m radio telescope and resulted in the detection of 105 new 95 GHz class I methanol masers. For 92 of the sources our observations...
Source: http://arxiv.org/abs/1107.2914v1
Arxiv.org
by C. Adam; J. Sanchez-Guillen; A. Wereszczynski
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Within the set of generalized Skyrme models, we identify a submodel which has both infinitely many symmetries and a Bogomolny bound which is saturated by infinitely many exact soliton solutions. Concretely, the submodel consists of the square of the baryon current and a potential term only. Further, already on the classical level, this BPS Skyrme model reproduces some features of the liquid drop model of nuclei. Here, we review the properties of the model and we discuss the semiclassical...
Source: http://arxiv.org/abs/1107.5433v2
Arxiv.org
by Sangjib Kim; Oded Yacobi
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The symplectic group branching algebra, B, is a graded algebra whose components encode the multiplicities of irreducible representations of Sp(2n-2,C) in each irreducible representation of Sp(2n,C). By describing on B an ASL structure, we construct an explicit standard monomial basis of B consisting of Sp(2n-2,C) highest weight vectors. Moreover, B is known to carry a canonical action of the n-fold product SL(2) \times ... \times SL(2), and we show that the standard monomial basis is the unique...
Source: http://arxiv.org/abs/1005.2320v2
Arxiv.org
by Xiaolei Xun; Bani Mallick; Raymond J. Carroll; Peter Kuchment
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The article addresses the problem of detecting presence and location of a small low emission source inside of an object, when the background noise dominates. This problem arises, for instance, in some homeland security applications. The goal is to reach the signal-to-noise ratio (SNR) levels on the order of $10^{-3}$. A Bayesian approach to this problem is implemented in 2D. The method allows inference not only about the existence of the source, but also about its location. We derive Bayes...
Source: http://arxiv.org/abs/1107.2980v1
Arxiv.org
by A. R. Conn; G. F. Lewis; R. A. Ibata; Q. A. Parker; D. B. Zucker; A. W. McConnachie; N. F. Martin; M. J. Irwin; N. Tanvir; M. A. Fardal; A. M. N. Ferguson
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We present a new approach for identifying the Tip of the Red Giant Branch (TRGB) which, as we show, works robustly even on sparsely populated targets. Moreover, the approach is highly adaptable to the available data for the stellar population under study, with prior information readily incorporable into the algorithm. The uncertainty in the derived distances is also made tangible and easily calculable from posterior probability distributions. We provide an outline of the development of the...
Source: http://arxiv.org/abs/1107.3206v1
Arxiv.org
by Eric B. Ford; Althea V. Moorhead; Dimitri Veras
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We present a Bayesian surrogate model for the analysis of periodic or quasi-periodic time series data. We describe a computationally efficient implementation that enables Bayesian model comparison. We apply this model to simulated and real exoplanet observations. We discuss the results and demonstrate some of the challenges for applying our surrogate model to realistic exoplanet data sets. In particular, we find that analyses of real world data should pay careful attention to the effects of...
Source: http://arxiv.org/abs/1107.4047v1
Arxiv.org
by Yuriy Mishchencko; Joshua T. Vogelstein; Liam Paninski
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Deducing the structure of neural circuits is one of the central problems of modern neuroscience. Recently-introduced calcium fluorescent imaging methods permit experimentalists to observe network activity in large populations of neurons, but these techniques provide only indirect observations of neural spike trains, with limited time resolution and signal quality. In this work we present a Bayesian approach for inferring neural circuitry given this type of imaging data. We model the network...
Source: http://arxiv.org/abs/1107.4228v1
Arxiv.org
by Philipp Gubler; Makoto Oka
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QCD sum rules are analyzed with the help of the Maximum Entropy Method. We develop a new technique based on the Bayesion inference theory, which allows us to directly obtain the spectral function of a given correlator from the results of the operator product expansion given in the deep euclidean 4-momentum region. The most important advantage of this approach is that one does not have to make any a priori assumptions about the functional form of the spectral function, such as the "pole +...
Source: http://arxiv.org/abs/1005.2459v2
Arxiv.org
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We consider scheduling packets with values in a capacity-bounded buffer in an online setting. In this model, there is a buffer with limited capacity $B$. At any time, the buffer cannot accommodate more than $B$ packets. Packets arrive over time. Each packet is associated with a non-negative value. Packets leave the buffer only because they are either sent or dropped. Those packets that have left the buffer will not be reconsidered for delivery any more. In each time step, at most one packet in...
Source: http://arxiv.org/abs/1005.3835v3
Arxiv.org
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The Boltzmann collision operator for a dilute granular gas of inelastic rough hard spheres is much more intricate than its counterpart for inelastic smooth spheres. Now the one-body distribution function depends not only on the translational velocity of the center of mass but also on the angular velocity of the particle. Moreover, the collision rules couple both velocities, involving not only the coefficient of normal restitution but also the coefficient of tangential restitution. The aim of...
Source: http://arxiv.org/abs/1007.0700v2
Arxiv.org
by Blanca Ayuso de Dios; Ariel Lombardi; Paola Pietra; Ludmil Zikatanov
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We consider an exponentially fitted discontinuous Galerkin method and propose a robust block solver for the resulting linear systems.
Source: http://arxiv.org/abs/1107.2831v1
Arxiv.org
by Daoyuan Fang; Ruizhao Zi; Ting Zhang
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We establish a blow-up criterion in terms of the upper bound of the density and temperature for the strong solution to 2D compressible viscous heat-conductive flows. The initial vacuum is allowed.
Source: http://arxiv.org/abs/1107.4663v1
Arxiv.org
by Walid Hachem; Malika Kharouf; Jamal Najim; Jack W. Silverstein
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In this article, we study the fluctuations of the random variable: $$ {\mathcal I}_n(\rho) = \frac 1N \log\det(\Sigma_n \Sigma_n^* + \rho I_N),\quad (\rho>0) $$ where $\Sigma_n= n^{-1/2} D_n^{1/2} X_n\tilde D_n^{1/2} +A_n$, as the dimensions of the matrices go to infinity at the same pace. Matrices $X_n$ and $A_n$ are respectively random and deterministic $N\times n$ matrices; matrices $D_n$ and $\tilde D_n$ are deterministic and diagonal, with respective dimensions $N\times N$ and $n\times...
Source: http://arxiv.org/abs/1107.0145v1
Arxiv.org
by Luc Simard; J. Trevor Mendel; David R. Patton; Sara L. Ellison; Alan W. McConnachie
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We perform two-dimensional, Point-Spread-Function-convolved, bulge+disk decompositions in the $g$ and $r$ bandpasses on a sample of 1,123,718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in...
Source: http://arxiv.org/abs/1107.1518v1
Arxiv.org
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We use a Stochastic Differential Equation satisfied by Brownian motion taking values in the unit sphere $S_{n-1}subsetmathbb{R}^{n}$ and we obtain a Central Limit Theorem for a sequence of such Brownian motions. We also generalize the results to the case of the $n$-dimensional Ornstein-Uhlenbeck processes.
Source: http://arxiv.org/abs/1107.3230v3
Arxiv.org
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New observations show that the lightcurve of Kuiper belt contact binary (139775) 2001 QG298 has changed substantially since the first observations in 2003. The 2010 lightcurve has a peak-to-peak photometric of range \Deltam{2010}=0.7\pm0.1 mag, significantly lower than in 2003, \Deltam{2003}=1.14\pm0.04 mag. This change is most simply interpreted if 2001 QG298 has an obliquity near 90 deg. The observed decrease in \Deltam is caused by a change in viewing geometry, from equator-on in 2003 to...
Source: http://arxiv.org/abs/1107.3507v1
Arxiv.org
by H. R. Jacobson; C. A. Pilachowski; E. D. Friel
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We present a detailed chemical abundance study of evolved stars in 10 open clusters based on Hydra multi-object echelle spectra obtained with the WIYN 3.5m telescope. From an analysis of both equivalent widths and spectrum synthesis, abundances have been determined for the elements Fe, Na, O, Mg, Si, Ca, Ti, Ni, Zr, and for two of the 10 clusters, Al and Cr. To our knowledge, this is the first detailed abundance analysis for clusters NGC 1245, NGC 2194, NGC 2355 and NGC 2425. These 10 clusters...
Source: http://arxiv.org/abs/1107.4139v1
Arxiv.org
by Shin Isojima; Junkichi Satsuma
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A class of special solutions are constructed in an intuitive way for the ultradiscrete analog of $q$-Painlev\'e II ($q$-PII) equation. The solutions are classified into four groups depending on the function-type and the system parameter.
Source: http://arxiv.org/abs/1107.4416v1
Arxiv.org
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The derivation of the Born rule by Zurek uses a "splitting procedure" where a physical state is subdivided into a number of states. It is argued that in quantum field theory, which encompasses quantum mechanics, such a procedure would in general modify the physics.
Source: http://arxiv.org/abs/1107.3736v1
Arxiv.org
by Joshua D. Simon; Marla Geha; Quinn E. Minor; Gregory D. Martinez; Evan N. Kirby; James S. Bullock; Manoj Kaplinghat; Louis E. Strigari; Beth Willman; Philip I. Choi; Erik J. Tollerud; Joe Wolf
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We present the results of a comprehensive Keck/DEIMOS spectroscopic survey of the ultra-faint Milky Way satellite galaxy Segue 1. We have obtained velocity measurements for 98.2% of the stars within 67 pc (10 arcmin, or 2.3 half-light radii) of the center of Segue 1 that have colors and magnitudes consistent with membership, down to a magnitude limit of r=21.7. Based on photometric, kinematic, and metallicity information, we identify 71 stars as probable Segue 1 members, including some as far...
Source: http://arxiv.org/abs/1007.4198v3
Arxiv.org
by W. P. Birmingham; C. J. Meek
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We propose a model for errors in sung queries, a variant of the hidden Markov model (HMM). This is a solution to the problem of identifying the degree of similarity between a (typically error-laden) sung query and a potential target in a database of musical works, an important problem in the field of music information retrieval. Similarity metrics are a critical component of query-by-humming (QBH) applications which search audio and multimedia databases for strong matches to oral queries. Our...
Source: http://arxiv.org/abs/1107.0054v1
Arxiv.org
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The notion of weak truth-table reducibility plays an important role in recursion theory. In this paper, we introduce an elaboration of this notion, where a computable bound on the use function is explicitly specified. This elaboration enables us to deal with the notion of asymptotic behavior in a manner like in computational complexity theory, while staying in computability theory. We apply the elaboration to sets which appear in the statistical mechanical interpretation of algorithmic...
Source: http://arxiv.org/abs/1107.3746v1
Arxiv.org
by R. A. Gutermuth; J. L. Pipher; S. T. Megeath; P. C. Myers; L. E. Allen; T. S. Allen
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We report the discovery and characterization of a power law correlation between the local surface densities of Spitzer-identified, dusty young stellar objects and the column density of gas (as traced by near-IR extinction) in eight molecular clouds within 1 kpc and with 100 or more known YSOs. This correlation, which appears in data smoothed over size scales of ~1 pc, varies in quality from cloud to cloud; those clouds with tight correlations, MonR2 and Ophiuchus, are fit with power laws of...
Source: http://arxiv.org/abs/1107.0966v1
Arxiv.org
by Sundar Vishwanathan
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We give a counting based proof of the Graham Pollak Theorem
Source: http://arxiv.org/abs/1007.1553v2
Arxiv.org
by M. Ferrero; D. Salgado; J. L. Sanchez-Gomez
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It is argued that the traditional "realist" methodology of physics, according to which human concepts, laws and theories can grasp the essence of reality, is incompatible with the most fruitful interpretation of quantum formalism. The proof rests on the violation by quantum mechanics of the foundational principles of that methodology. An alternative methodology, in which the construction of sciences finishes at the level of human experience, as standard quantum theory strongly...
Source: http://arxiv.org/abs/1107.3366v1
Arxiv.org
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The bin packing problem is to find the minimum number of bins of size one to pack a list of items with sizes $a_1,..., a_n$ in $(0,1]$. Using uniform sampling, which selects a random element from the input list each time, we develop a randomized $O({n(\log n)(\log\log n)\over \sum_{i=1}^n a_i}+({1\over \epsilon})^{O({1\over\epsilon})})$ time $(1+\epsilon)$-approximation scheme for the bin packing problem. We show that every randomized algorithm with uniform random sampling needs $\Omega({n\over...
Source: http://arxiv.org/abs/1007.1260v3
Arxiv.org
by Y. Fukui; H. Sano; J. Sato; K. Torii; H. Horachi; T. Hayakawa; N. M. McClure-Griffiths; G. Rowell; T. Inoue; S. Inutsuka; A. Kawamura; H. Yamamoto; T. Okuda; N. Mizuno; T. Onishi; A. Mizuno; H. Ogawa
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RX J1713.7$-$3946 is the most remarkable TeV $\gamma$-ray SNR which emits $\gamma$-rays in the highest energy range. We made a new combined analysis of CO and \ion{H}{1} in the SNR and derived the total protons in the interstellar medium (ISM). We have found that the inclusion of the \ion{H}{1} gas provides a significantly better spatial match between the TeV $\gamma$-rays and ISM protons than the H$_2$ gas alone. In particular, the southeastern rim of the $\gamma$-ray shell has a counterpart...
Source: http://arxiv.org/abs/1107.0508v4
Arxiv.org
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This paper considers sparse linear discriminant analysis of high-dimensional data. In contrast to the existing methods which are based on separate estimation of the precision matrix $\O$ and the difference $\de$ of the mean vectors, we introduce a simple and effective classifier by estimating the product $\O\de$ directly through constrained $\ell_1$ minimization. The estimator can be implemented efficiently using linear programming and the resulting classifier is called the linear programming...
Source: http://arxiv.org/abs/1107.3442v1
Arxiv.org
by Tony Gherghetta; Alex Pomarol
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We show that when supersymmetry is broken at the TeV scale by strong dynamics, the Higgs sector of the MSSM can be drastically modified. This arises from possible sizeable mixings of the Higgs with the resonances of the strong sector. In particular the mass of the lightest Higgs boson can be significantly above the MSSM bound (~130 GeV). Furthermore only one Higgs doublet is strictly necessary, because the Yukawa couplings can have a very different structure compared to the MSSM. Using the...
Source: http://arxiv.org/abs/1107.4697v2
Arxiv.org
by Ermin Wei; Asuman Ozdaglar; Ali Jadbabaie
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Most existing work uses dual decomposition and subgradient methods to solve Network Utility Maximization (NUM) problems in a distributed manner, which suffer from slow rate of convergence properties. This work develops an alternative distributed Newton-type fast converging algorithm for solving network utility maximization problems with self-concordant utility functions. By using novel matrix splitting techniques, both primal and dual updates for the Newton step can be computed using iterative...
Source: http://arxiv.org/abs/1005.2633v2
Arxiv.org
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We show that the three-dimensional layers-of-maxima problem can be solved in $o(n\log n)$ time in the word RAM model. Our algorithm runs in $O(n(\log \log n)^3)$ deterministic time or $O(n(\log\log n)^2)$ expected time and uses O(n) space. We also describe an algorithm that uses optimal O(n) space and solves the three-dimensional layers-of-maxima problem in $O(n\log n)$ time in the pointer machine model.
Source: http://arxiv.org/abs/1007.1593v2
Arxiv.org
by Necdet Serhat Aybat; Garud Iyengar
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We propose a first-order augmented Lagrangian algorithm (FAL) for solving the basis pursuit problem. FAL computes a solution to this problem by inexactly solving a sequence of L1-regularized least squares sub-problems. These sub-problems are solved using an infinite memory proximal gradient algorithm wherein each update reduces to "shrinkage" or constrained "shrinkage". We show that FAL converges to an optimal solution of the basis pursuit problem whenever the solution is...
Source: http://arxiv.org/abs/1005.5582v2
Arxiv.org
by Mark D. Roberts
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In a certain sense a perfect fluid is a generalization of a point particle. This leads to the question as to what is the corresponding generalization for extended objects. The lagrangian formulation of a perfect fluid is much generalized and this has as a particular example a fluid which is a classical generalization of a membrane, however there is as yet no indication of any relationship between their quantum theories.
Source: http://arxiv.org/abs/hep-th/0406164v2
Arxiv.org
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We study twisted ideal sheaves of small length on an irreducible principally polarized abelian surface (T,l). Using Fourier-Mukai techniques we associate certain jumping schemes to such sheaves and completely classify such loci. We give examples of applications to the enumerative geometry of T and show that no smooth genus 5 curve on such a surface can contain a g^1_3. We also describe explicitly the singular divisors in the linear system |2l|.
Source: http://arxiv.org/abs/1107.2549v2
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by Bing Zeng; Xueming Tang; Chingfang Hsu
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We present a framework for fully-simulatable $h$-out-of-$n$ oblivious transfer ($OT^{n}_{h}$) with security against non-adaptive malicious adversaries. The framework costs six communication rounds and costs at most $40n$ public-key operations in computational overhead. Compared with the known protocols for fully-simulatable oblivious transfer that works in the plain mode (where there is no trusted common reference string available) and proven to be secure under standard model (where there is no...
Source: http://arxiv.org/abs/1005.0043v3
Arxiv.org
by Salvatore Catanese; Emilio Ferrara; Giacomo Fiumara; Francesco Pagano
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The process of design and development of virtual environments can be supported by tools and frameworks, to save time in technical aspects and focusing on the content. In this paper we present an academic framework which provides several levels of abstraction to ease this work. It includes state-of-the-art components we devised or integrated adopting open-source solutions in order to face specific problems. Its architecture is modular and customizable, the code is open-source.
Source: http://arxiv.org/abs/1107.0690v1
Arxiv.org
by Albert Banchs; Andres Garcia-Saavedra; Pablo Serrano; Joerg Widmer
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Distributed Opportunistic Scheduling (DOS) is inherently harder than conventional opportunistic scheduling due to the absence of a central entity that has knowledge of all the channel states. With DOS, stations contend for the channel using random access; after a successful contention, they measure the channel conditions and only transmit in case of a good channel, while giving up the transmission opportunity when the channel conditions are poor. The distributed nature of DOS systems makes them...
Source: http://arxiv.org/abs/1107.4452v1
Arxiv.org
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Using ergodic theory, in this paper we present a Gel'fand-type spectral radius formula which states that the joint spectral radius is equal to the generalized spectral radius for a matrix multiplicative semigroup $\bS^+$ restricted to a subset that need not carry the algebraic structure of $\bS^+$. This generalizes the Berger-Wang formula. Using it as a tool, we study the absolute exponential stability of a linear switched system driven by a compact subshift of the one-sided Markov shift...
Source: http://arxiv.org/abs/1107.0124v1
Arxiv.org
by Fano W. G.; S. Boggi; A. C. Razzitte
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This paper is devoted to the study and the obtaining of the general relation between the real part and the imaginary part of the magnetic susceptibility function in the Laplace domain. This new theoretical technique is general, and can be applied to any magnetic material, that can be considered like causal and Linear time invariant (LTI). A discussion of the causality which is extensively used in Physics has been done. To obtain the relations, some important concepts like Titchmarsh's theorem...
Source: http://arxiv.org/abs/1107.0419v1
Arxiv.org
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In a previous paper, we defined an operation $\mu$ that generalizes Turaev's cobracket for loops on a surface. We showed that, in contrast to the cobracket, this operation gives a formula for the minimum number of self-intersections of a loop in a given free homotopy class. In this paper we consider the corresponding question for virtual strings. We show that $\mu$ gives a bound on the minimal self-intersection number of a virtual string which is stronger than a bound given by Turaev's virtual...
Source: http://arxiv.org/abs/1107.4718v1
Arxiv.org
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The definition and measurement of magnetic reconnection in three-dimensional magnetic fields with multiple reconnection sites is a challenging problem, particularly in fields lacking null points. We propose a generalization of the familiar two-dimensional concept of a magnetic flux function to the case of a three-dimensional field connecting two planar boundaries. Using hyperbolic fixed points of the field line mapping, and their global stable and unstable manifolds, we define a unique flux...
Source: http://arxiv.org/abs/1107.0594v1
Arxiv.org
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A lower bound on the minimum error probability for multihypothesis testing is established. The bound, which is expressed in terms of the cumulative distribution function of the tilted posterior hypothesis distribution given the observation with tilting parameter theta larger than or equal to 1, generalizes an earlier bound due the Poor and Verdu (1995). A sufficient condition is established under which the new bound (minus a multiplicative factor) provides the exact error probability in the...
Source: http://arxiv.org/abs/1107.3474v1
Arxiv.org
by Aaron Smith
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We determine the mixing time of a simple Gibbs sampler on the unit simplex, confirming a conjecture of D. Aldous. The upper bound is based on a two-step coupling, where the first step is a simple contraction argument and the second step is a non-Markovian coupling. We also present a MCMC-based perfect sampling algorithm that is based on our proof and which can be applied to Gibbs samplers that are harder to analyze.
Source: http://arxiv.org/abs/1107.5829v1
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We review an approach to observation-theory comparisons we call "Taste-Testing." In this approach, synthetic observations are made of numerical simulations, and then both real and synthetic observations are "tasted" (compared) using a variety of statistical tests. We first lay out arguments for bringing theory to observational space rather than observations to theory space. Next, we explain that generating synthetic observations is only a step along the way to the...
Source: http://arxiv.org/abs/1107.2827v1
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by Jason Baggett; Odile Bastille; Alexei Rybkin
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We discuss a new numerical schema for solving the initial value problem for the Korteweg-de Vries equation for large times. Our approach is based upon the Inverse Scattering Transform that reduces the problem to calculating the reflection coefficient of the corresponding Schr\"odinger equation. Using a step-like approximation of the initial profile and a fragmentation principle for the scattering data, we obtain an explicit recursion formula for computing the reflection coefficient,...
Source: http://arxiv.org/abs/1107.3540v1
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by Cyril Imbert; Régis Monneau; Hasnaa Zidani
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This paper is concerned with the study of a model case of first order Hamilton-Jacobi equations posed on a "junction", that is to say the union of a finite number of half-lines with a unique common point. The main result is a comparison principle. We also prove existence and stability of solutions. The two challenging difficulties are the singular geometry of the domain and the discontinuity of the Hamiltonian. As far as discontinuous Hamiltonians are concerned, these results seem to...
Source: http://arxiv.org/abs/1107.3250v2
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In Type III seesaw model the heavy neutrinos are contained in leptonic triplet representations. The Yukawa couplings of the triplet fermion and the left-handed neutrinos with the doublet Higgs field produce the Dirac mass terms. Together with the Majorana masses for the leptonic triplets, the light neutrinos obtain non-zero seesaw masses. We point out that it is also possible to have a quadruplet Higgs field to produce the Dirac mass terms to facilitate the seesaw mechanism. The vacuum...
Source: http://arxiv.org/abs/1107.5879v2
Arxiv.org
by Chris Aholt; Bernd Sturmfels; Rekha Thomas
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Multiview geometry is the study of two-dimensional images of three-dimensional scenes, a foundational subject in computer vision. We determine a universal Groebner basis for the multiview ideal of n generic cameras. As the cameras move, the multiview varieties vary in a family of dimension 11n-15. This family is the distinguished component of a multigraded Hilbert scheme with a unique Borel-fixed point. We present a combinatorial study of ideals lying on that Hilbert scheme.
Source: http://arxiv.org/abs/1107.2875v1
Arxiv.org
by Bum-Hoon Lee; Da-Wei Pang; Chanyong Park
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We give a review on our recent work arXiv:1006.0779 [hep-th] and arXiv:1006.1719 [hep-th], in which properties of holographic strange metals were investigated. The background is chosen to be anisotropic scaling solution in Einstein-Maxwell-Dilaton theory with a Liouville potential. The effects of bulk Maxwell field, an extra U(1) gauge field and probe D-branes on the DC conductivity, the DC Hall conductivity and the AC conductivity are extensively analyzed. We classify behaviors of the...
Source: http://arxiv.org/abs/1107.5822v2
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by Sakura Schafer-Nameki; Carlos Tamarit; Gonzalo Torroba
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We construct composite Higgs models admitting a weakly coupled Seiberg dual description. We focus on the possibility that only the up-type Higgs is an elementary field, while the down-type Higgs arises as a composite hadron. The model, based on a confining SQCD theory, breaks supersymmetry and electroweak symmetry dynamically and calculably. This simultaneously solves the \mu/B_\mu problem and explains the smallness of the bottom and tau masses compared to the top mass. The proposal is then...
Source: http://arxiv.org/abs/1005.0841v3
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by Raphaël Danchin; Piotr Bogus\law Mucha
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Here we investigate the Cauchy problem for the inhomogeneous Navier-Stokes equations in the whole $n$-dimensional space. Under some smallness assumption on the data, we show the existence of global-in-time unique solutions in a critical functional framework. The initial density is required to belong to the multiplier space of $\dot B^{n/p-1}_{p,1}(\R^n)$. In particular, piecewise constant initial densities are admissible data \emph{provided the jump at the interface is small enough}, and...
Source: http://arxiv.org/abs/1107.2763v1
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by Matthew D. Johnston; David Siegel; Gábor Szederkényi
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A numerically effective procedure for determining weakly reversible chemical reaction networks that are linearly conjugate to a known reaction network is proposed in this paper. The method is based on translating the structural and algebraic characteristics of weak reversibility to logical statements and solving the obtained set of linear (in)equalities in the framework of mixed integer linear programming. The unknowns in the problem are the reaction rate coefficients and the parameters of the...
Source: http://arxiv.org/abs/1107.1659v1
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by Tomasz Kociumaka; Marcin Kubica; Jakub Radoszewski; Wojciech Rytter; Tomasz Walen
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Periodicity in words is one of the most fundamental areas of text algorithms and combinatorics. Two classical and natural variations of periodicity are seeds and covers (also called quasiperiods). Linear-time algorithms are known for finding all the covers of a word, however in case of seeds, for the past 15 years only an $O(n\log{n})$ time algorithm was known (Iliopoulos, Moore and Park, 1996). Finding an $o(n\log{n})$ time algorithm for the all-seeds problem was mentioned as one of the most...
Source: http://arxiv.org/abs/1107.2422v1
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by Can Baskent
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Notion of strategy in game theory is static and presumably constructed before the game play. The static, pre-determined notion of strategies falls short analyzing perfect information games. Because, we, people, do not strategize as such even in perfect information games - largely because we are not logically omniscient, and we have limited computational power and bounded memory. In this paper, we focus on what we call move updates where some moves become unavailable during the game. Our goal...
Source: http://arxiv.org/abs/1107.4931v1
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We review and then combine two aspects of the theory of bundle gerbes. The first concerns lifting bundle gerbes and connections on those, developed by Murray and Gomi. Lifting gerbes represent obstructions against extending the structure group of a principal bundle. The second is the transgression of gerbes to loop spaces, initiated by Brylinski and McLaughlin and with recent contributions of the author. Combining these two aspects, we obtain a new formulation of lifting problems in terms of...
Source: http://arxiv.org/abs/1007.5373v2
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by James W. Anderson; Aaron Wootton
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We prove that the number of distinct group actions on compact Riemann surfaces of a fixed genus $\sigma \geq 2$ is at least quadratic in $\sigma$. We do this through the introduction of a coarse signature space, the space $\mathcal{K}_\sigma$ of {\em skeletal signatures} of group actions on compact Riemann surfaces of genus $\sigma$. We discuss the basic properties of $\mathcal{K}_\sigma$ and present a full conjectural description.
Source: http://arxiv.org/abs/1107.3433v2
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by Calanit Dotan; Elena M. Rossi; Nir J. Shaviv
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We consider a scenario where supermassive black holes form through direct accumulation of gas at the centre of proto-galaxies. In the first stage, the accumulated gas forms a super-massive star whose core collapses when the nuclear fuel is exhausted, forming a black hole of $M_{\rm BH} \approx 100 M_{\sun}$. As the black hole starts accreting, it inflates the surrounding dense gas into an almost hydrostatic self-gravitating envelope, with at least 10-100 times the mass of the hole. We find that...
Source: http://arxiv.org/abs/1107.3562v1
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by Fabien Campillo; Dominique Hervé; Angelo Raherinirina; Rivo Rakotozafy
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The application of the Markov chain to modeling agricultural succession is well known. In most cases, the main problem is the inference of the model, i.e. the estimation of the transition matrix. In this work we present methods to estimate the transition matrix from historical observations. In addition to the estimator of maximum likelihood (MLE), we also consider the Bayes estimator associated with the Jeffreys prior. This Bayes estimator will be approximated by a Markov chain Monte Carlo...
Source: http://arxiv.org/abs/1107.0785v1
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by Jie Sun; Erik M. Bollt; Mason A. Porter; Marian S. Dawkins
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We formulate a mathematical model for daily activities of a cow (eating, lying down, and standing) in terms of a piecewise affine dynamical system. We analyze the properties of this bovine dynamical system representing the single animal and develop an exact integrative form as a discrete-time mapping. We then couple multiple cow "oscillators" together to study synchrony and cooperation in cattle herds. We comment on the relevant biology and discuss extensions of our model. With this...
Source: http://arxiv.org/abs/1005.1381v2
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by D. Cohen; M. Cooper; P. Jeavons; A. Krokhin
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Many researchers in artificial intelligence are beginning to explore the use of soft constraints to express a set of (possibly conflicting) problem requirements. A soft constraint is a function defined on a collection of variables which associates some measure of desirability with each possible combination of values for those variables. However, the crucial question of the computational complexity of finding the optimal solution to a collection of soft constraints has so far received very...
Source: http://arxiv.org/abs/1107.0043v1
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by D. T. O'Dea; C. N. Clark; C. R. Contaldi; C. J. MacTavish
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The upcoming generation of cosmic microwave background (CMB) experiments face a major challenge in detecting the weak cosmic B-mode signature predicted as a product of primordial gravitational waves. To achieve the required sensitivity these experiments must have impressive control of systematic effects and detailed understanding of the foreground emission that will influence the signal. In this paper, we present templates of the intensity and polarisation of emission from one of the main...
Source: http://arxiv.org/abs/1107.4612v2
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We propose new equations of motion under the theory of the Brownian motion to connect the states of quantum, diffusion, soliton, and periodic localization. The new equations are nothing but the classical equations of motion with two additional terms and the one of them can be regarded as the the quantum potential. By choosing a parameter space, various important states are obtained. Further, the equations contain other interesting phenomena such as general dynamics of diffusion process,...
Source: http://arxiv.org/abs/1107.4329v1
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by D. W. Longcope; S. E. Guidoni
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Super-hot looptop sources, detected in some large solar flares, are compact sources of HXR emission with spectra matching thermal electron populations exceeding 30 megakelvins. High observed emission measure, as well as inference of electron thermalization within the small source region, both provide evidence of high densities at the looptop; typically more than an order of magnitude above ambient. Where some investigators have suggested such density enhancement results from a rapid enhancement...
Source: http://arxiv.org/abs/1107.2441v1
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by Michael G. Gowanlock; David R. Patton; Sabine M. McConnell
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We present a model of the Galactic Habitable Zone (GHZ), described in terms of the spatial and temporal dimensions of the Galaxy that may favour the development of complex life. The Milky Way galaxy is modelled using a computational approach by populating stars and their planetary systems on an individual basis using Monte-Carlo methods. We begin with well-established properties of the disk of the Milky Way, such as the stellar number density distribution, the initial mass function, the star...
Source: http://arxiv.org/abs/1107.1286v1
Smarandache Geometries and Curves
by F. Smarandache
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In this article we present the two classical negations of Euclid’s Fifth Postulate (done by Lobachevski-Bolyai-Gauss, and respectively by Riemann), and in addition of these we propose a partial negation (or a degree of negation) of an axiom in geometry.
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by Najmul Haque; Munshi G. Mustafa
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Based on the external perturbation that disturbs the system only slightly from its equilibrium position we make the Taylor expansion of the pressure of a quark gas. It turns out that the first term was used in the literature to construct a Hard Thermal Loop perturbation theory (HTLpt) within the variation principle of the lowest order of the thermal mass parameter. Various thermodynamic quantities within the 1-loop HTLpt encountered overcounting of the leading order (LO) contribution and also...
Source: http://arxiv.org/abs/1007.2076v3
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by Alex L. Castro; Wyatt C. Howard
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We consider here the problem of classifying orbits of an action of the dif- feomorphism group of 3-space on a tower of fibrations with P2-fibers that generalize the Monster Tower due to Montgomery and Zhitomirskii. As a corollary we give the first steps towards the problem of classifying Goursat 2-flags of small length. In short, we classify the orbits within the first four levels of the Monster Tower and show that there is a total of 34 orbits at the fourth level in the tower.
Source: http://arxiv.org/abs/1107.4145v1
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by John Marriner; J. P. Bernstein; Richard Kessler; Hubert Lampeitl; Ramon Miquel; Jennifer Mosher; Robert C. Nichol; Masao Sako; Donald P. Schneider; Mathew Smith
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We describe a new formalism to fit the parameters $\alpha$ and $\beta$ that are used in the SALT2 model to determine the standard magnitudes of Type Ia supernovae. The new formalism describes the intrinsic scatter in Type Ia supernovae by a covariance matrix in place of the single parameter normally used. We have applied this formalism to the Sloan Digital Sky Survey Supernova Survey (SDSS-II) data and conclude that the data are best described by $\alpha=0.135_{-.017}^{+.033}$ and...
Source: http://arxiv.org/abs/1107.4631v2
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by Qun Lin; Hehu Xie
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In this paper, a new type of multi-level correction scheme is proposed for solving eigenvalue problems by finite element method. With this new scheme, the accuracy of eigenpair approximations can be improved after each correction step which only needs to solve a source problem on finer finite element space and an eigenvalue problem on the coarsest finite element space. This correction scheme can improve the efficiency of solving eigenvalue problems by finite element method.
Source: http://arxiv.org/abs/1107.0223v1
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by A. Liam Fitzpatrick; Jared Kaplan; Joao Penedones; Suvrat Raju; Balt C. van Rees
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We provide dramatic evidence that `Mellin space' is the natural home for correlation functions in CFTs with weakly coupled bulk duals. In Mellin space, CFT correlators have poles corresponding to an OPE decomposition into `left' and `right' sub-correlators, in direct analogy with the factorization channels of scattering amplitudes. In the regime where these correlators can be computed by tree level Witten diagrams in AdS, we derive an explicit formula for the residues of Mellin amplitudes at...
Source: http://arxiv.org/abs/1107.1499v2
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by Takayuki R. Saitoh; Junichiro Makino
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We propose a symmetrized form of the softened gravitational potential which is a natural extension of the Plummer potential. The gravitational potential at the position of particle i (x_i,y_i,z_i), induced by particle j at (x_j,y_j,z_j), is given by: phi_ij = -G m_j/|r_ij^2+e_i^2+e_j^2|^1/2, where G is the gravitational constant, m_j is the mass of particle j, r_ij = |(x_i-x_j)^2+(y_i-y_j)^2+(z_i-z_j)^2|^1/2 and e_i and e_j are the gravitational softening lengths of particles i and j,...
Source: http://arxiv.org/abs/1005.1752v2
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We demonstrate that an extremely small but positive quantum correction, or the Casimir energy, to the cosmological constant can arise from a massive bulk fermion field in the Randall-Sundrum model. Specifically, a cosmological constant doubly descended from the Planck-electroweak hierarchy and as minute as the observed dark energy scale can be naturally achieved without fine-tuning of the bulk fermion mass. To ensure the stabilization of the system, we discuss two stabilization mechanisms under...
Source: http://arxiv.org/abs/1005.1920v3
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by Jin Zhang; Peter Ade; Philip Mauskopf; Lorenzo Moncelsi; Giorgio Savini; Nicola Whitehouse
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We describe a novel artificial dielectric material which has applications at millimetre and submillimetre wavelengths. The material is manufactured from layers of metal mesh patterned onto thin polypropylene sheets which are then bonded together using a hot pressing process to provide planar rugged discs which can be reliably cycled to cryogenic temperatures. The refractive index of this material can be tuned by adjusting the geometry and spacing of the metal-mesh layers. We demonstrate its...
Source: http://arxiv.org/abs/1107.3560v1
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We extend Br\"and\'en's recent proof of a conjecture of Stanley and describe a new class of non-linear operators that preserve weak Hurwitz stability and the Laguerre-P\'olya class.
Source: http://arxiv.org/abs/1005.4252v2
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by Blair C. Conn; Anna Pasquali; Emanuela Pompei; Richard R. Lane; André-Nicolas Chené; Rory Smith; Geraint F. Lewis
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We report the serendipitous discovery of a collision ring galaxy, identified as 2MASX J06470249+4554022, which we have dubbed 'Auriga's Wheel', found in a SUPRIME-CAM frame as part of a larger Milky Way survey. This peculiar class of galaxies is the result of a near head-on collision between typically, a late type and an early type galaxy. Subsequent GMOS-N long-slit spectroscopy has confirmed both the relative proximity of the components of this interacting pair and shown it to have a redshift...
Source: http://arxiv.org/abs/1107.4099v2
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Assuming that the universe is homogenous and isotropic and applying Gauss' flux theorem for gravity, it follows that the gravitational field of the visible universe can be calculated as if the entire mass of the visible universe is located in one point. Taking into account that the mass of the visible universe is M=2x10^{53} kg, it appears that the entire visible universe is inside a {\it photon sphere} of radius R_{ps} = 14.3 Gpc. The current model for the visible universe must be corrected to...
Source: http://arxiv.org/abs/1005.4387v9
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For every natural number $T,$ we write $\Ln T$ as a series, generalizing the known series for $\Ln 2.$
Source: http://arxiv.org/abs/1107.4731v1
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by Maria Pilar Garcia del Moral
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We provide a mechanism of gauging a theory based on a particular way to embed a theory on a target space such that a nontrivial fibration is produced. A connection over a nontrivial fibration with monodromy provides a natural framework for a new way of gauging a theory. Moreover, properties of the global symmetry of the original theory are included in a particular way in the new theory. This mechanism for gauging a symmetry preserves the total number of degrees of freedom in distinction with...
Source: http://arxiv.org/abs/1107.3255v1
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by Laura J. Hainline; Christopher W. Morgan; J. N. Beach; C. S. Kochanek; Hugh C. Harris; T. Tilleman; Ross Fadely; Emilio E. Falco; T. X. Le
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We present evidence for ultraviolet/optical microlensing in the gravitationally lensed quasar Q0957+561. We combine new measurements from our optical monitoring campaign at the United States Naval Observatory, Flagstaff (USNO) with measurements from the literature and find that the time-delay-corrected r-band flux ratio m_A - m_B has increased by ~0.1 magnitudes over a period of five years beginning in the fall of 2005. We apply our Monte Carlo microlensing analysis procedure to the composite...
Source: http://arxiv.org/abs/1107.0982v2
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We employ the method used by Barbashov and collaborators in Quantum Field Theory to derive a path-integral representation of the $T$-matrix in nonrelativistic potential scattering which is free of functional integration over fictitious variables as was necessary before. The resulting expression serves as a starting point for a variational approximation applied to high-energy scattering from a Gaussian potential. Good agreement with exact partial-wave calculations is found even at large...
Source: http://arxiv.org/abs/1107.3034v2
Dezert-Smarandache Theory of plausible and paradoxist reasoning
by Hu Lifang; He You; Guan Xin; Deng Yong; Han Deqiang
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The mapping from the belief to the probability domain is a controversial issue, whose original purpose is to make (hard) decision, but for contrariwise to erroneous widespread idea/claim, this is not the only interest for using such mappings nowadays. Actually the probabilistic transformations of belief mass assignments are very useful in modern multitarget multisensor tracking systems where one deals with soft decisions, especially when precise belief structures are not always available due to...
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by John D. Barrow; Douglas J. Shaw
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We extend the usual gravitational action principle by promoting the bare cosmological constant (CC) from a parameter to a field which can take many possible values. Variation leads to a new integral constraint equation which determines the classical value of the effective CC that dominates the wave function of the universe. In a realistic cosmological model, the expected value of the effective CC, is calculated from measurable quantities to be O(t_U), as observed, where t_U is the present age...
Source: http://arxiv.org/abs/1007.3086v3
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by Mohamed A. Mabrok; Abhijit G. Kallapur; Ian R. Petersen; Alexander Lanzon
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This paper is concerned with stability conditions for the positive feedback interconnection of negative imaginary systems. A generalization of the negative imaginary lemma is derived, which remains true even if the transfer function has poles on the imaginary axis including the origin. A sufficient condition for the internal stability of a feedback interconnection for NI systems including a pole at the origin is given and an illustrative example is presented to support the result.
Source: http://arxiv.org/abs/1107.4255v1
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We perform a study of the LHC discovery reach on a heavy gluon (G*) and heavy fermions (top and bottom excitations), coming from a new composite sector. We find that heavy fermion resonances have a great impact on the composite gluon phenomenology. If the composite gluon is heavier than composite fermions, as flavor observables seem to suggest, the search in the channel where G* decays into a heavy fermion plus its Standard Model partner is very promising, with the possibility for both the G*...
Source: http://arxiv.org/abs/1107.4558v2
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This paper presents a new classifier combination technique based on the Dempster-Shafer theory of evidence. The Dempster-Shafer theory of evidence is a powerful method for combining measures of evidence from different classifiers. However, since each of the available methods that estimates the evidence of classifiers has its own limitations, we propose here a new implementation which adapts to training data so that the overall mean square error is minimized. The proposed technique is shown to...
Source: http://arxiv.org/abs/1107.0018v1
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by Philip R. Heath; P. Christopher Staecker
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As the title suggests, this paper gives a Nielsen theory of coincidences of iterates of two self maps f, g of a closed manifold. The ideas is, as much as possible, to generalize Nielsen type periodic point theory, but there are many obstacles. Many times we get similar results to the "classical ones" in Nielsen periodic point theory, but with stronger hypotheses.
Source: http://arxiv.org/abs/1107.5510v1
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by Amrita Bhattacharya; Ramil Izmailov; Ettore Laserra; Kamal K. Nandi
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In a recent paper, we showed the Jordan frame vacuum Brans Class I solution provided a wormhole analogue to Horowitz-Ross naked black hole in the wormhole range -3/2
Source: http://arxiv.org/abs/1107.5994v1
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by Yochay Jerby
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A classical way to construct a Lagrangian in a symplectic manifold $\Sigma$ is to let $\Sigma$ appear as a smooth fiber in a Lefschetz fibration. If this is possible the singularities of the fibration induce Lagrangian spheres in $\Sigma$ and these spheres, in turn, are representatives of the corresponding vanishing cycles in the homology of $\Sigma$. In this paper our aim is twofold: The first is to describe a generalization of the above mentioned construction to the "Morse-Bott"...
Source: http://arxiv.org/abs/1005.5657v3
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by Selman Akbulut; M. Firat Arikan
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Loi-Piergallini and Akbulut-Ozbagci showed that every compact Stein surface admits a Lefschetz fibration over the 2-disk with bounded fibers. In this note we give a more intrinsic alternative proof of this result.
Source: http://arxiv.org/abs/1007.3643v3
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For the positive integer $n$, let $f(n)$ denote the number of positive integer solutions $(n_1,\,n_2,\,n_3)$ of the Diophantine equation $$ {4\over n}={1\over n_1}+{1\over n_2}+{1\over n_3}. $$ For the prime number $p$, $f(p)$ can be split into $f_1(p)+f_2(p),$ where $f_i(p)(i=1,\,2)$ counts those solutions with exactly $i$ of denominators$n_1,\,n_2,\,n_3$ divisible by $p.$ Recently Terence Tao proved that $$ \sum_{p < x}f_2(p)\ll x\log^2x\log\log x $$ with other results. But actually only...
Source: http://arxiv.org/abs/1107.5394v1
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by U. Battisti; S. Coriasco
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We prove an extension to R^n, endowed with a suitable metric, of the relation between the Einstein-Hilbert action and the Dirac operator which holds on closed spin manifolds. By means of complex powers, we first define the regularised Wodzicki Residue for a class of operators globally defined on R^n. The result is then obtained by using the properties of heat kernels and generalised Laplacians.
Source: http://arxiv.org/abs/1007.1797v2
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by Ranjan Pal; Leana Golubchik; Konstantinos Psounis
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Internet users such as individuals and organizations are subject to different types of epidemic risks such as worms, viruses, and botnets. To reduce the probability of risk, an Internet user generally invests in self-defense mechanisms like antivirus and antispam software. However, such software does not completely eliminate risk. Recent works have considered the problem of residual risk elimination by proposing the idea of cyber-insurance. In reality, an Internet user faces risks due to...
Source: http://arxiv.org/abs/1107.4785v1
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by Felipe Cucker; Teresa Krick; Gregorio Malajovich; Mario Wschebor
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In a recent paper (Cucker, Krick, Malajovich and Wschebor, A Numerical Algorithm for Zero Counting. I: Complexity and accuracy, J. Compl.,24:582-605, 2008) we analyzed a numerical algorithm for computing the number of real zeros of a polynomial system. The analysis relied on a condition number kappa(f) for the input system f. In this paper, we look at kappa(f) as a random variable derived from imposing a probability measure on the space of polynomial systems and give bounds for both the tail...
Source: http://arxiv.org/abs/1007.1597v2
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by Yaroslav D. Sergeyev; Dmitri E. Kvasov; Falah M. H. Khalaf
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Lipschitz one-dimensional constrained global optimization (GO) problems where both the objective function and constraints can be multiextremal and non-differentiable are considered in this paper. Problems, where the constraints are verified in an a priori given order fixed by the nature of the problem are studied. Moreover, if a constraint is not satisfied at a point, then the remaining constraints and the objective function can be undefined at this point. The constrained problem is reduced to...
Source: http://arxiv.org/abs/1107.5280v1
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by M. H. Goker; P. Langley; C. A. Thompson
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Searching for and making decisions about information is becoming increasingly difficult as the amount of information and number of choices increases. Recommendation systems help users find items of interest of a particular type, such as movies or restaurants, but are still somewhat awkward to use. Our solution is to take advantage of the complementary strengths of personalized recommendation systems and dialogue systems, creating personalized aides. We present a system -- the Adaptive Place...
Source: http://arxiv.org/abs/1107.0029v1
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by Claudio M. G. de Sousa; Evandro A. de Araujo
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We use standard polynomial expansion technique to show the existence of a relation between polytropic model and the description of gas spheres at finite temperature. A numerical analysis is made concerning the obtained perturbative parameters. It is shown that there is a correspondence between polytropic and gas sphere thermal models for fermions and bosons. For instance, the polytropic index $n$ displays evident correlation with temperature and chemical potential.
Source: http://arxiv.org/abs/1007.1994v2