19,256 research outputs found

    Multifractal Analysis of The New Level Sets

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    By an appropriate definition, we divide the irregular set into level sets. Then we characterize the multifractal spectrum of these new pieces by calculating their entropies. We also compute the entropies of various intersections of the level sets of regular and irregular set which is rarely studied in the literature. Moreover, our conclusions also hold for the topological pressure. Finally, we consider the continuous case and use our results to give a description for the suspension flow

    Study of the Spin-weighted Spheroidal Wave Equation in the Case of s=3/2

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    In this paper, we use the means of super-symmetric quantum mechanics to study of the Spin-weighted Spheroidal Wave in the case of s=3/2. We obtain some interesting results: the first-five terms of the super-potential, the general form of the super-potential. The ground eigen-function and eigenvalue of the equation are also given. According these results, we make use of the shape invariance property to compute the exited eigenvalues and eigen-functions. These results help us to understand the Spin-weighted Spheroidal Wave and show that it is integral.Comment: arXiv admin note: substantial text overlap with arXiv:1011.257

    On a C. de Boor's Conjecture in a Particular Case and Related Perturbation

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    In this paper, we focus on two classes of D-invariant polynomial subspaces. The first is a classical type, while the second is a new class. With matrix computation, we prove that every ideal projector with each D-invariant subspace belonging to either the first class or the second is the pointwise limit of Lagrange projectors. This verifies a particular case of a C. de Boor's conjecture asserting that every complex ideal projector is the pointwise limit of Lagrange projectors. Specifically, we provide the concrete perturbation procedure for ideal projectors of this type

    On the irregular points for systems with the shadowing property

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    We prove that when ff is a continuous selfmap acting on compact metric space (X,d)(X,d) which satisfies the shadowing property, then the set of irregular points (i.e. points with divergent Birkhoff averages) has full entropy. Using this fact we prove that in the class of C0C^0-generic maps on manifolds, we can only observe (in the sense of Lebesgue measure) points with convergant Birkhoff averages. In particular, the time average of atomic measures along orbit of such points converges to some SRB-like measure in the weakβˆ—^* topology. Moreover, such points carry zero entropy. In contrast, irregular points are non-observable but carry infinite entropy

    DNS Study on Vorticity Structures in Late Flow Transition

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    Vorticity and vortex are two different but related concepts. This paper focuses on the investigation of vorticity generation and development, and vorticity structure inside/ outside the vortex. Vortex is a region where the vorticity overtakes deformation. Vortex cannot be directly represented by the vorticity. Except for those vorticity lines which come from and end at side boundaries, another type of vorticity, self-closed vorticity lines named vorticity rings, is numerously generated inside the domain during flow transition. These new vorticity rings are found around the hairpin vortex heads and legs. The generation and growth of vorticity rings are produced by the buildup of the vortices according to the vorticity transport equation. On the other hand, vortex buildup is a consequence of vorticity line stretching, tilting and twisting. Both new vorticity and new vortices are generated during the flow transition. According to the Helmholtz vorticity flux conservation law, vorticity line cannot be interrupted, started, or ended inside the flow field, the newly produced vorticity has only one form which is the vorticity rings. In addition, an interesting finding is that a single hairpin vortex consists of several types of vorticity lines which could come from the side boundaries, whole vorticity rings and part of vorticity rings

    The Spin-weighted Spheroidal Wave functions in the Case of s=1/2

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    The spin-weighted spheroidal equations in the case s=1/2 is thoroughly studied in the paper by means of the perturbation method in supersymmetry quantum mechanics. The first-five terms of the super-potential in the series of the parameter beta are given. The general form of the nth term of the superpotential is also obtained, which could derived from the previous terms W_{k}, k<n. From the results, it is easy to give the ground eigenfunction of the equation. Furthermore, the shape-invariance property is investigated in the series form of the parameter beta and is proven kept in this series form for the equations. This nice property guarantee one could obtain the excited eigenfunctions in the series form from the ground eigenfunctions by the method in supersymmetry quantum mechanics. This shows the perturbation method method in supersymmetry quantum mechanics could solve the spin-weight spheroidal wave equations completely in the series form of the small parameter beta

    On existence of certain error formulas for a special class of ideal projectors

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    In this paper, we focus on a special class of ideal projectors. With the aid of algebraic geometry, we prove that for this special class of ideal projectors, there exist "good" error formulas as defined by C. de Boor. Furthermore, we completely analyze the properties of the interpolation conditions matched by this special class of ideal projectors, and show that the ranges of this special class of ideal projectors are the minimal degree interpolation spaces with regard to their associated interpolation conditions

    A Circumbinary Disk Model for the Rapid Orbital Shrinkage in Black Hole Low-Mass X-ray Binaries

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    Several black hole low-mass X-ray binaries (BHLMXBs) show very fast orbital shrinkage, which is difficult to understand in the standard picture of the LMXB evolution. Based on the possible detection of a circumbinary (CB) disk in A0620-00 and XTE J1118+480, we investigate the influence of the interaction between a CB disk and the inner binary and calculate the evolution of the binary using the Modules for Experiments in Stellar Astrophysics. We consider two cases for the CB disk formation in which it is fed by mass loss during single outburst or successive outbursts in the LMXB. We show that when taking reasonable values of the initial mass and the dissipating time of the disk, it is possible to explain the fast orbital shrinkage in the BHLMXBs without invoking high mass transfer rate.Comment: 17 pages, 9 figures, accepted by Ap

    Finite Sets of Affine Points with Unique Associated Monomial Order Quotient Bases

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    The quotient bases for zero-dimensional ideals are often of interest in the investigation of multivariate polynomial interpolation, algebraic coding theory, and computational molecular biology, etc. In this paper, we discuss the properties of zero-dimensional ideals with unique monomial quotient bases, and verify that the vanishing ideals of Cartesian sets have unique monomial quotient bases. Furthermore, we reveal the relation between Cartesian sets and the point sets with unique associated monomial quotient bases

    A Bivariate Preprocessing Paradigm for Buchberger-M\"oller Algorithm

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    For the last almost three decades, since the famous Buchberger-M\"oller(BM) algorithm emerged, there has been wide interest in vanishing ideals of points and associated interpolation polynomials. Our paradigm is based on the theory of bivariate polynomial interpolation on cartesian point sets that gives us related degree reducing interpolation monomial and Newton bases directly. Since the bases are involved in the computation process as well as contained in the final output of BM algorithm, our paradigm obviously simplifies the computation and accelerates the BM process. The experiments show that the paradigm is best suited for the computation over finite prime fields that have many applications.Comment: 24 pages, 7 figures, submitted to JCA
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