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61.
Giuseppe Albertini 《Journal of statistical physics》1998,90(3-4):853-871
The transition from the ordered commensurate phase to the incommensurate Gaussian phase of the antiferroelectric asymmetric six-vertex model is investigated by keeping the temperature constant below the roughening point and varying the external fields (h, v). In the (h, v) plane, the phase boundary is approached along straight lines v = k h, where (h, v) measures the displacement from the phase boundary. It is found that the free energy singularity displays the exponent 3/2 typical of the Pokrovski–Talapov transition f const(h)3/2 for any direction other than the tangential one. In the latter case f shows a discontinuity in the third derivative. 相似文献
62.
We consider some reaction–diffusion equations perturbed by white noise and prove Schauder estimates for the elliptic problem
associated with the generator of the corresponding transition semigroup, defined in the Banach space of continuous functions.
This requires the proof of some new interpolation result. 相似文献
63.
Vittorio Colao Giuseppe Marino Luigi Muglia 《Applied mathematics and computation》2012,218(11):6232-6241
Starting by a finite family of mappings, we define the concept of procedure with Lipschitzian dependence of the coefficients. We give seven concrete examples of such procedures and prove the strong convergence of two viscosity methods. 相似文献
64.
A. Othman Almatroud Amina-Aicha Khennaoui Adel Ouannas Giuseppe Grassi M. Mossa Al-sawalha Ahlem Gasri 《Entropy (Basel, Switzerland)》2020,22(12)
This article proposes a new fractional-order discrete-time chaotic system, without equilibria, included two quadratic nonlinearities terms. The dynamics of this system were experimentally investigated via bifurcation diagrams and largest Lyapunov exponent. Besides, some chaotic tests such as the 0–1 test and approximate entropy (ApEn) were included to detect the performance of our numerical results. Furthermore, a valid control method of stabilization is introduced to regulate the proposed system in such a way as to force all its states to adaptively tend toward the equilibrium point at zero. All theoretical findings in this work have been verified numerically using MATLAB software package. 相似文献
65.
Luca Esposito Francesco Leonetti Giuseppe Mingione 《NoDEA : Nonlinear Differential Equations and Applications》1999,6(2):133-148
We prove higher integrability for the gradient of vector-valued minimizers of some integral functionals with p – q growth.
Received February 9, 1998 相似文献
66.
We consider an extension of the set union problem, in which dynamic weighted backtracking over sequences of unions is permitted. We present a new data structure which can support each operation inO(logn) time in the worst case. We prove that this bound is tight for pointer based algorithms. Furthermore, we design a different data structure to achieve better amortized bounds. The space complexity of both our data structures isO(n). Motivations for studying this problem arise in logic programming memory management.Work partially supported by NSF Grant CCR-88-14977, by the ESPRIT II Basic Research Actions Program of the EC under contract No. 3075 (Project ALCOM), and by the Italian MURST Project Algoritmi e Strutture di Calcolo.Partially supported by an IBM Graduate Fellowship. 相似文献
67.
68.
Giuseppe Savaré 《Numerische Mathematik》1993,65(1):319-335
Summary We study the approximation of linear parabolic Cauchy problems by means of Galerkin methods in space andA -stable multistep schemes of arbitrary order in time. The error is evaluated in the norm ofL
t
2
(H
x
1
) L
t
(L
x
2
). 相似文献
69.
Giuseppe Pirillo 《Results in Mathematics》1993,24(1-2):168-173
Let h and k be integers greater than 1; we prove that the following statements are equivalent: 1) the direct product of h copies of the additive semigroup of non-negative integers is not k-repetitive; 2) if the direct product of h finitely generated semigroups is k-repetitive, then one of them is finite. Using this and some results of Dekking and Pleasants on infinite words, we prove that certain repetitivity properties are finiteness conditions for finitely generated semigroups. 相似文献
70.
For every and every integer N, let be the minimum of the distance of τ from the sums , where . We prove that , for all sufficiently large positive integers N (depending on C and τ), where C is any positive constant less than . 相似文献