共查询到20条相似文献,搜索用时 15 毫秒
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N. M. Plakida 《Theoretical and Mathematical Physics》2011,168(3):1303-1317
Based on constructing the equations of motion for the two-time Green’s functions, we discuss calculating the dynamical spin
susceptibility and correlation functions in the Heisenberg model. Using a Mori-type projection, we derive an exact Dyson equation
with the self-energy operator in the form of a multiparticle Green’s function. Calculating the self-energy operator in the
mode-coupling approximation in the ferromagnetic phase, we reproduce the results of the temperature diagram technique, including
the correct formula for low-temperature magnetization. We also consider calculating the spin fluctuation spectrum in the paramagnetic
phase in the framework of the method of equations of motion for the relaxation function. 相似文献
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Baumslag??s group is a finitely presented metabelian group with a ${\mathbb Z \wr \mathbb Z}$ subgroup. There is an analogue with an additional torsion relation in which this subgroup becomes ${C_m \wr \mathbb Z}$ . We prove that Baumslag??s group has an exponential Dehn function. This contrasts with the torsion analogues which have quadratic Dehn functions. 相似文献
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Dijkstra’s algorithm is a well-known algorithm for the single-source shortest path problem in a directed graph with nonnegative edge length. We discuss Dijkstra’s algorithm from the viewpoint of discrete convex analysis, where the concept of discrete convexity called L-convexity plays a central role. We observe first that the dual of the linear programming (LP) formulation of the shortest path problem can be seen as a special case of L-concave function maximization. We then point out that the steepest ascent algorithm for L-concave function maximization, when applied to the LP dual of the shortest path problem and implemented with some auxiliary variables, coincides exactly with Dijkstra’s algorithm. 相似文献
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Zubeyir Cinkir 《Inventiones Mathematicae》2011,183(3):517-562
We prove the Effective Bogomolov Conjecture, and so the Bogomolov Conjecture, over a function field of characteristic 0 by
proving Zhang’s Conjecture about certain invariants of metrized graphs. In the function field case, these conjectures were
previously known to be true only for curves of good reduction, for curves of genus at most 4 and a few other special cases.
We also either verify or improve the previous results. We relate the invariants involved in Zhang’s Conjecture to the tau
constant of metrized graphs. Then we use and extend our previous results on the tau constant. By proving another Conjecture
of Zhang, we obtain a new proof of the slope inequality for Faltings heights on moduli space of curves. 相似文献
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In recent papers the authors presented their approach to Feynman’s operational calculi for a system of not necessarily commuting
bounded linear operators acting on a Banach space. The central objects of the theory are the disentangling algebra, a commutative
Banach algebra, and the disentangling map which carries this commutative structure into the noncommutative algebra of operators.
Under assumptions concerning the growth of disentangled exponential expressions, the associated functional calculus for the
system of operators is a distribution with compact support which we view as the joint spectrum of the operators with respect
to the disentangling map. In this paper, the functional calculus is represented in terms of a higher-dimensional analogue
of the Riesz-Dunford calculus using Clifford analysis. 相似文献
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We study the Dirichlet problem for non-homogeneous equations involving the fractional p-Laplacian. We apply Perron’s method and prove Wiener’s resolutivity theorem. 相似文献
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Eleftherios N. Nikolidakis 《Israel Journal of Mathematics》2017,219(2):507-528
We precisely evaluate the Bellman function of two variables of the dyadic maximal operator related to Kolmogorov’s inequality, thus giving an alternative proof of the results in [3]. Additionally, we characterize the sequences of functions that are extremal for this Bellman function. More precisely, we prove that they behave approximately like eigenfunctions of the dyadic maximal operator, for a specific eigenvalue. 相似文献
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M. Jutila 《Mathematical Notes》2010,88(3-4):612-616
We prove that an appropriately modified Mellin transform of the Hardy function Z(x) Is en entire function. The proof is based on the fact that the function (21?s ? 1)ζ(s) is integer. 相似文献
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Juan Arias de Reyna Jan van de Lune 《Journal of Mathematical Analysis and Applications》2012,396(1):199-214
For any real we determine the supremum of the real such that for some real . For , , and the results turn out to be quite different.We also determine the supremum of the real parts of the ‘turning points’, that is points where a curve has a vertical tangent. This supremum (also considered by Titchmarsh) coincides with the supremum of the real such that for some real .We find a surprising connection between the three indicated problems: , and turning points of . The almost extremal values for these three problems appear to be located at approximately the same height. 相似文献
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Nobushige Kurokawa Katsuhisa Mimachi Masato Wakayama 《Rendiconti del Circolo Matematico di Palermo》2007,56(1):43-56
We give a Jacksonq-integral analogue of Euler’s logarithmic sine integral established in 1769 from several points of view, specifically from
the one relating to the Hurwitz zeta function.
Partially supported by Grant-in-Aid for Exploratory Research No. 15654003.
Partially supported by Grant-in-Aid for Scientific Research (B) No. 15340003.
Partially supported by Grant-in-Aid for Scientific Research (B) No. 15340012. 相似文献
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M. A. Korolev 《Monatshefte für Mathematik》2012,168(3-4):403-441
We study an asymptotic behavior of the sum ${\sum_{n \leqslant x} \frac{\tau(n)}{\tau(n+a)}}$ . Here τ(n) denote the number of divisors of n and ${a\,\geqslant\,1}$ is a fixed integer. 相似文献
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S. M. Robinson published in 1980 a powerful theorem about solutions to certain “generalized equations” corresponding to parameterized variational inequalities which could represent the first-order optimality conditions in nonlinear programming, in particular. In fact, his result covered much of the classical implicit function theorem, if not quite all, but went far beyond that in ideas and format. Here, Robinson’s theorem is viewed from the perspective of more recent developments in variational analysis as well as some lesser-known results in the implicit function literature on equations, prior to the advent of generalized equations. Extensions are presented which fully cover such results, translating them at the same time to generalized equations broader than variational inequalities. Robinson’s notion of first-order approximations in the absence of differentiability is utilized in part, but even looser forms of approximation are shown to furnish significant information about solutions. 相似文献