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891.
Milica Anđelić Domingos M. Cardoso Slobodan K. Simić 《Czechoslovak Mathematical Journal》2013,63(1):73-90
Let G be a finite graph with an eigenvalue µ of multiplicity m. A set X of m vertices in G is called a star set for µ in G if µ is not an eigenvalue of the star complement G\X which is the subgraph of G induced by vertices not in X. A vertex subset of a graph is (κ, τ)-regular if it induces a κ-regular subgraph and every vertex not in the subset has τ neighbors in it. We investigate the graphs having a (κ, τ)-regular set which induces a star complement for some eigenvalue. A survey of known results is provided and new properties for these graphs are deduced. Several particular graphs where these properties stand out are presented as examples. 相似文献
892.
Let $f$ be a real entire function whose set $S(f)$ of singular values is real and bounded. We show that, if $f$ satisfies a certain function-theoretic condition (the “sector condition”), then $f$ has no wandering domains. Our result includes all maps of the form $z\mapsto \lambda \frac{\sinh (z)}{z} + a$ with $\lambda >0$ and $a\in \mathbb{R }$ . We also show the absence of wandering domains for certain non-real entire functions for which $S(f)$ is bounded and $f^n|_{S(f)}\rightarrow \infty $ uniformly. As a special case of our theorem, we give a short, elementary and non-technical proof that the Julia set of the exponential map $f(z)=e^z$ is the entire complex plane. Furthermore, we apply similar methods to extend a result of Bergweiler, concerning Baker domains of entire functions and their relation to the postsingular set, to the case of meromorphic functions. 相似文献
893.
Let G n be the set of all real algebraic polynomials of degree at most n, positive on the interval (?1, 1) and without zeros inside the unit circle (|z| < 1). In this paper an inequality for the polynomials from the set G n is obtained. In one special case this inequality is reduced to the inequality given by B. Sendov [5] and in another special case it is reduced to an inequality between uniform norm and norm in the L 2 space for the Jacobi weight. 相似文献
894.
Mario Krnić Josip Pečarić Predrag Vuković 《Mediterranean Journal of Mathematics》2013,10(4):1697-1716
In this paper we provide a unified treatment of half-discrete Hilbert-type inequalities with a general homogeneous kernel. The main results are proved for the case of non-conjugate exponents. A special emphasis is given to determining conditions under which these inequalities include the best possible constants. As an application, we consider some operator expressions closely connected to established inequalities. Finally, we also provide improvements of derived half-discrete inequalities by virtue of the Hermite-Hadamard inequality. 相似文献
895.
896.
Pavle V.M. Blagojević Aleksandra Dimitrijević Blagojević Ljubiša D.R. Kočinac 《Topology and its Applications》2013
In this paper we give the complete answer to a question posed by A. Arhangel?skii and prove that the sphere Sn is diagonal resolvable if and only if Sn is an H -space if and only if n∈{0,1,3,7}. Moreover, we prove that any upper half even dimensional Q-sphere cannot be diagonal resolvable. 相似文献
897.
898.
Ivan P. Stanimirović 《Journal of Applied Mathematics and Computing》2013,42(1-2):193-211
We transform a continuous Weber problem with barriers to a discrete problem by computing some efficient locations, which are considered as promising locations for a new facility. A theorem determining conditions for a location to be efficient is introduced. A method for constructing the weighted coefficients and travel costs modeled by some distance metrics, is derived. This method provides successive computation of some efficient locations. Also, we propose an algorithm for the verification of location’s efficiency. Numerical examples are provided using squared Euclidean and Manhattan distance metrics, as well as the implementation details in programming package MATHEMATICA. 相似文献
899.
Multi body system contains finite number of rigid bodies that are placed on each axis, which do not intersect each other. Derivatives of the linear momentum and angular momentum with respect to time by use mass moment vectors and vector rotators for pole and axis, are determined. A number of theorems are defined. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
900.
We consider a mixture of N ideal, polytropic gases. Each species is described by a distribution function fi(t, x, v, I) ≥ 0, 1 ≤ i ≤ N, defined on , and its evolution is governed by a Boltzmann-type equation. In order to recover the energy law of polytropic gases, the authors of [4] proposed a kinetic model in the framework of a weighted L1 space. Another approach has been developed in [3] in the context of polyatomic gases. Following this previous lead, our model provides a L2 framework in both variables v and I, to eventually perform a mathematical study of the diffusion asymptotics, as it was done in [2] for a model without energy exchange. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献