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1.0

Jun 28, 2018
06/18

by
Deepak Bal; Louis DeBiasio

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Erd\H{o}s, Gy\'arf\'as, and Pyber (1991) conjectured that every $r$-colored complete graph can be partitioned into at most $r-1$ monochromatic components; this is a strengthening of a conjecture of Lov\'asz (1975) in which the components are only required to form a cover. An important partial result of Haxell and Kohayakawa (1995) shows that a partition into $r$ monochromatic components is possible for sufficiently large $r$-colored complete graphs. We start by extending Haxell and Kohayakawa's...

Topics: Combinatorics, Mathematics

Source: http://arxiv.org/abs/1509.09168

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1.0

Jun 26, 2018
06/18

by
Shuichi Hirahara

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We provide a general framework to remove short advice by formulating the following computational task for a function $f$: given two oracles at least one of which is honest (i.e. correctly computes $f$ on all inputs) as well as an input, the task is to compute $f$ on the input with the help of the oracles by a probabilistic polynomial-time machine, which we shall call a selector. We characterize the languages for which short advice can be removed by the notion of selector: a paddable language...

Topics: Computing Research Repository, Computational Complexity

Source: http://arxiv.org/abs/1502.07258

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Jun 27, 2018
06/18

by
Hong Zhu; Zhi-Qiang Jiang; Sai-Ping Li; Wei-Xing Zhou

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Although technical trading rules have been widely used by practitioners in financial markets, their profitability still remains controversial. We here investigate the profitability of moving average (MA) and trading range break (TRB) rules by using the Shanghai Stock Exchange Composite Index (SHCI) from May 21, 1992 through December 31, 2013 and Shenzhen Stock Exchange Composite Index (SZCI) from April 3, 1991 through December 31, 2013. The $t$-test is adopted to check whether the mean returns...

Topics: Quantitative Finance, Trading and Market Microstructure, Statistical Finance

Source: http://arxiv.org/abs/1504.04254

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3.0

Jun 27, 2018
06/18

by
László Babai; John Wilmes

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We give a new bound on the parameter $\lambda$ (number of common neighbors of a pair of adjacent vertices) in a distance-regular graph $G$, improving and generalizing bounds for strongly regular graphs by Spielman (1996) and Pyber (2014). The new bound is one of the ingredients of recent progress on the complexity of testing isomorphism of strongly regular graphs (Babai, Chen, Sun, Teng, Wilmes 2013). The proof is based on a clique geometry found by Metsch (1991) under certain constraints on...

Topics: Data Structures and Algorithms, Combinatorics, Computing Research Repository, Discrete Mathematics,...

Source: http://arxiv.org/abs/1503.02746

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16

Jun 26, 2018
06/18

by
Matthias Mauch; Robert M. MacCallum; Mark Levy; Armand M. Leroi

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In modern societies, cultural change seems ceaseless. The flux of fashion is especially obvious for popular music. While much has been written about the origin and evolution of pop, most claims about its history are anecdotal rather than scientific in nature. To rectify this we investigate the US Billboard Hot 100 between 1960 and 2010. Using Music Information Retrieval (MIR) and text-mining tools we analyse the musical properties of ~17,000 recordings that appeared in the charts and...

Topics: Sound, Physics, Physics and Society, Computing Research Repository

Source: http://arxiv.org/abs/1502.05417

3
3.0

Jun 28, 2018
06/18

by
P. H. Lundow; I. A. Campbell

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Ising spin glasses with bimodal and Gaussian near-neighbor interaction distributions are studied through numerical simulations. The non-self-averaging (normalized inter-sample variance) parameter $U_{22}(T,L)$ for the spin glass susceptibility (and for higher moments $U_{nn}(T,L)$) is reported for dimensions 2, 3, 4, 5 and 7. In each dimension $d$ the non-self-averaging parameters in the paramagnetic regime vary with the sample size L and the correlation length $\xi(T,L)$ as $U_{nn}(\beta,L) =...

Topics: Disordered Systems and Neural Networks, Condensed Matter

Source: http://arxiv.org/abs/1508.03368

3
3.0

Jun 27, 2018
06/18

by
Ricardo A. Maronna; Victor J. Yohai

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We deal with the equivariant estimation of scatter and location for p-dimensional data, giving emphasis to scatter. It it important that the estimators possess both a high efficiency for normal data and a high resistance to outliers, that is, a low bias under contamination. The most frequently employed estimators are not quite satisfactory in this respect. The Minimum Volume Ellipsoid (MVE) and Minimum Covariance Determinant (MCD) estimators are known to have a very low efficiency. S-Estimators...

Topics: Statistics, Mathematics, Statistics Theory

Source: http://arxiv.org/abs/1504.03389

1
1.0

Jun 28, 2018
06/18

by
T. Szücs; D. Bemmerer; A. Caciolli; Zs. Fülöp; R. Massarczyk; C. Michelagnoli; T. P. Reinhardt; R. Schwengner; M. P. Takács; C. A. Ur; A. Wagner; L. Wagner

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The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the hydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton emission threshold are known from just one nuclear resonance fluorescence (NRF) measurement, with limited precision in some cases. A recent experiment with the AGATA demonstrator array determined level lifetimes using the Doppler Shift Attenuation Method (DSAM) in $^{15}$O. As a reference and for testing the method, level lifetimes in...

Topic: Nuclear Experiment

Source: http://arxiv.org/abs/1506.06027

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1.0

Jun 26, 2018
06/18

by
V. Arvind; Johannes Köbler; Gaurav Rattan; Oleg Verbitsky

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Color refinement is a classical technique used to show that two given graphs G and H are non-isomorphic; it is very efficient, although it does not succeed on all graphs. We call a graph G amenable to color refinement if it succeeds in distinguishing G from any non-isomorphic graph H. Tinhofer (1991) explored a linear programming approach to Graph Isomorphism and defined compact graphs: A graph is compact if its fractional automorphisms polytope is integral. Tinhofer noted that isomorphism...

Topics: Combinatorics, Mathematics, Discrete Mathematics, Computing Research Repository, Computational...

Source: http://arxiv.org/abs/1502.01255

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2.0

Jun 27, 2018
06/18

by
Artur Czumaj; Peter Davies

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We present two optimal randomized leader election algorithms for multi-hop radio networks, which run in expected time asymptotically equal to the time required to broadcast one message to the entire network. We first observe that, under certain assumptions, a simulation approach of Bar-Yehuda, Golreich and Itai (1991) can be used to obtain an algorithm that for directed and undirected networks elects a leader in $O(D \log\frac{n}{D} + \log^2 n)$ expected time, where $n$ is the number of the...

Topics: Distributed, Parallel, and Cluster Computing, Computing Research Repository

Source: http://arxiv.org/abs/1505.06149

4
4.0

Jun 28, 2018
06/18

by
Sandro Claudio Lera; Didier Sornette

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We study the performance of the euro/Swiss franc exchange rate in the extraordinary period from September 6, 2011 and January 15, 2015 when the Swiss National Bank enforced a minimum exchange rate of 1.20 Swiss francs per euro. Based on the analogy between Brownian motion in finance and physics, the first-order effect of such a steric constraint would enter a priori in the form of a repulsive entropic force associated with the paths crossing the barrier that are forbidden. Non-parametric...

Topics: Quantitative Finance, Statistical Finance

Source: http://arxiv.org/abs/1508.04754

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0.0

Jun 28, 2018
06/18

by
Luke B. Smith; Montserrat Fuentes; Penny Gordon-Larsen; Brian J. Reich

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Cardiometabolic diseases have substantially increased in China in the past 20 years and blood pressure is a primary modifiable risk factor. Using data from the China Health and Nutrition Survey, we examine blood pressure trends in China from 1991 to 2009, with a concentration on age cohorts and urbanicity. Very large values of blood pressure are of interest, so we model the conditional quantile functions of systolic and diastolic blood pressure. This allows the covariate effects in the middle...

Topics: Statistics, Applications

Source: http://arxiv.org/abs/1511.01641

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0.0

Jun 28, 2018
06/18

by
Jānis Priede; Thomas Arlt; Leo Bühler

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This study is concerned with numerical linear stability analysis of liquid metal flow in a square duct with thin electrically conducting walls subject to a uniform transverse magnetic field. We derive an asymptotic solution for the base flow which is valid not only for high but also moderate magnetic fields. This solution shows that for low wall conductance ratios $c\ll1,$ an extremely strong magnetic field with the Hartmann number $Ha\sim c^{-4}$ is required to attain the asymptotic flow...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1510.09222

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2.0

Jun 26, 2018
06/18

by
Bernard S. Kay; Umberto Lupo

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We conjecture that (when the notion of Hadamard state is suitably adapted) there is no isometry-invariant Hadamard state for the massive or massless covariant Klein-Gordon equation defined on the region of the Kruskal spacetime to the left of a surface of constant Schwarzschild radius in the right Schwarzschild wedge when Dirichlet boundary conditions are put on that surface. We also prove that, with a suitable definition for 'boost-invariant Hadamard state' (which we call 'strongly...

Topics: High Energy Physics - Theory, Mathematics, General Relativity and Quantum Cosmology, Mathematical...

Source: http://arxiv.org/abs/1502.06582

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4.0

Jun 26, 2018
06/18

by
A. Noutsos; C. Sobey; V. I. Kondratiev; P. Weltevrede; J. P. W. Verbiest; A. Karastergiou; M. Kramer; M. Kuniyoshi; A. Alexov; R. P. Breton; A. V. Bilous; S. Cooper; H. Falcke; J. -M. Grießmeier; T. E. Hassall; J. W. T. Hessels; E. F. Keane; S. Osłowski; M. Pilia; M. Serylak; B. W. Stappers; S. ter Veen; J. van Leeuwen; K. Zagkouris; K. Anderson; L. Bähren; M. Bell; J. Broderick; D. Carbone; Y. Cendes; T. Coenen; S. Corbel; J. Eislöffel; R. Fender; H. Garsden; P. Jonker; C. Law; S. Marko; J. Masters; J. Miller-Jones; G. Molenaar; R. Osten; M. Pietka; E. Rol; A. Rowlinson; B. Scheers; H. Spreeuw; T. Staley; A. Stewart; J. Swinbank; R. Wijers; R. Wijnands; M. Wise; P. Zarka; A. van der Horst

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We present the highest-quality polarisation profiles to date of 16 non-recycled pulsars and four millisecond pulsars, observed below 200 MHz with the LOFAR high-band antennas. Based on the observed profiles, we perform an initial investigation of expected observational effects resulting from the propagation of polarised emission in the pulsar magnetosphere and the interstellar medium. The predictions of magnetospheric birefringence in pulsars have been tested using spectra of the pulse width...

Topics: Astrophysics, Astrophysics of Galaxies, High Energy Astrophysical Phenomena

Source: http://arxiv.org/abs/1501.03312

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5.0

Jun 26, 2018
06/18

by
Andrew D. Bragg; Peter J. Ireland; Lance R. Collins

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`Preferential concentration' (\emph{Phys. Fluids} \textbf{A3}:1169--78, 1991) refers to the clustering of inertial particles in the high-strain, low-rotation regions of turbulence. The `centrifuge mechanism' of Maxey (\emph{J. Fluid Mech.} \textbf{174}:441--65, 1987) appears to explain this phenomenon. In a recent paper, Bragg \& Collins (\emph{New J. Phys.} \textbf{16}:055013, 2014) showed that the centrifuge mechanism is dominant only in the regime ${St\ll1}$, where $St$ is the Stokes...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1501.03842

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0.0

Jun 28, 2018
06/18

by
Kai-Lung Sun; Jürgen Schmidt; Frank Spahn

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A kinky and clumpy ringlet shares orbit with the moon Pan in the center of the 320-km wide Encke gap in Saturn's rings (Porco et al., 2005). The ringlet is mainly composed of micron-sized particles (Showalter, 1991, Hedman et al., 2011), implying that these particles may be significantly perturbed by non-gravitational forces, which can limit their lifetimes. We establish a kinetic model considering the birth, evolution, and death of dust in the Encke central ringlet allowing to evaluate the...

Topics: Astrophysics, Earth and Planetary Astrophysics

Source: http://arxiv.org/abs/1510.07730

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2.0

Jun 28, 2018
06/18

by
T. S. Eaves; C. P. Caulfield

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We identify `minimal seeds' for turbulence, i.e. initial conditions of the smallest possible total perturbation energy density $E_c$ that trigger turbulence from the laminar state, in stably stratified plane Couette flow using the `direct-adjoint-looping' (DAL) method for finding nonlinear optimal perturbations that optimise the time averaged total dissipation of energy in the flow. These minimal seeds are located adjacent to the edge manifold, the manifold in state space that separates...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1509.06334

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9.0

Jun 27, 2018
06/18

by
Vladimir Derkach; Mark Malamud

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Let $A$ be a densely defined symmetric operator with equal deficiency indices in a Hilbert space. We introduce the notion of a Weyl function $M(z)$ of $A$ corresponding to an ordinary boundary triplet of the operator $A^*$ and then investigate its basic properties. In particular, a connection with Krein-Langer Q-functions and Krein's type formula for resolvents is discovered. Using this new connection, we show that the resolvent comparability of two proper extensions is equivalent to that of...

Topics: Spectral Theory, Mathematics

Source: http://arxiv.org/abs/1503.08956

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4.0

Jun 28, 2018
06/18

by
T. Mikosch; O. Wintenberger

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In this paper we propagate a large deviations approach for proving limit theory for (generally) multivariate time series with heavy tails. We make this notion precise by introducing regularly varying time series. We provide general large deviation results for functionals acting on a sample path and vanishing in some neighborhood of the origin. We study a variety of such functionals, including large deviations of random walks, their suprema, the ruin functional, and further derive weak limit...

Topics: Statistics, Statistics Theory, Mathematics

Source: http://arxiv.org/abs/1509.00253

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0.0

Jun 28, 2018
06/18

by
W. Kollatschny; N. Schartel; M. Zetzl; M. Santos-Lleó; P. M. Rodríguez-Pascual; L. Ballo; A. Talavera

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The object PG 0043+039 has been identified as a broad absorption line (BAL) quasar based on its UV spectra. However, this optical luminous quasar has not been detected before in deep X-ray observations, making it the most extreme X-ray weak quasar known today. This study aims to detect PG 0043+039 in a deep X-ray exposure. The question is what causes the extreme X-ray weakness of PG 0043+039? Does PG 0043+039 show other spectral or continuum peculiarities? We took simultaneous deep X-ray...

Topics: Astrophysics, Astrophysics of Galaxies

Source: http://arxiv.org/abs/1510.02681

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1.0

Jun 28, 2018
06/18

by
Amos Korman; Shay Kutten; Toshimitsu Masuzawa

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This paper demonstrates the usefulness of distributed local verification of proofs, as a tool for the design of self-stabilizing algorithms.In particular, it introduces a somewhat generalized notion of distributed local proofs, and utilizes it for improving the time complexity significantly, while maintaining space optimality. As a result, we show that optimizing the memory size carries at most a small cost in terms of time, in the context of Minimum Spanning Tree (MST). That is, we present...

Topics: Computing Research Repository, Distributed, Parallel, and Cluster Computing

Source: http://arxiv.org/abs/1512.07800

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1.0

Jun 27, 2018
06/18

by
Jakub Šístek; Jan Březina; Bedřich Sousedík

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We extend the Balancing Domain Decomposition by Constraints (BDDC) method to flows in porous media discretised by mixed-hybrid finite elements with combined mesh dimensions. Such discretisations appear when major geological fractures are modelled by 1D or 2D elements inside three-dimensional domains. In this set-up, the global problem as well as the substructure problems have a symmetric saddle-point structure, containing a `penalty' block due to the combination of meshes. We show that the...

Topics: Numerical Analysis, Mathematics

Source: http://arxiv.org/abs/1504.07085

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4.0

Jun 27, 2018
06/18

by
A. Araujo; H. Jennen; J. G. Pereira; A. C. Sampson; L. L. Savi

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As quotient spaces, Minkowski and de Sitter are fundamental, non-gravitational spacetimes for the construction of physical theories. When general relativity is constructed on a de Sitter spacetime, the usual Riemannian structure is replaced by a more general structure called de Sitter-Cartan geometry. In the contraction limit of an infinite cosmological term, the de Sitter-Cartan spacetime reduces to a singular, flat, conformal invariant four-dimensional cone spacetime, in which our ordinary...

Topics: General Relativity and Quantum Cosmology, High Energy Physics - Theory

Source: http://arxiv.org/abs/1503.05005