线性微分方程的非正规性与Gevrey类解(英文)

本文简要介绍了超函数(hyperfunction)的一个重要子类——Gevrey类超分布(ultra-distribution of Gevrey class),在此基础上介绍了线性微分算子的一些有关结果,并证明了线性双曲型方程 P(x,)u=f(x)的Cauchy问题,当算子P(x,)适合非正规性条件(irregularity condition)时,若定解资料属于Gevrey类,则它的解亦必属于该Gevrey类。     

GEVREY CLASS REGULARITY FOR THE GLOBAL ATTRACTOR OF A TWO-DIMENSIONAL NON-NEWTONIAN FLUID

This article investigates Gevrey class regularity for the global attractor of an incompressible non-Newtonian fluid in a two-dimensional domain with a periodic boundary condition.This Gevrey class regularity reveals that the solutions lying in the global attractor are analytic in time with values in a Gevrey class of analytic functions in space.     

高维复域中具非正则奇异性的非线性偏微分方程的形式解

本文在C_t×C_x~n上研究一类一阶具非正则奇异性的非线性偏微分方程.在一定条件下,证明了其形式幂级数解属于形式Gevrey类,并给出了其Gevrey类指标的精确刻画.     

Invariant hyperbolic tori for Gevrey-smooth Hamiltonian systems under Rüssmann’s non-degeneracy condition

In this paper, we prove the persistence of hyperbolic lower dimensional invariant tori for Gevrey-smooth perturbations of partially integrable Hamiltonian systems under Riissmann＇s nondegeneracy condition by an improved KAM iteration, and the persisting invariant tori are Gevrey smooth, with the same Gevrey index as the Hamiltonian.     

The Gevrey smoothing effect for the spatially inhomogeneous Boltzmann equations without cut-off

In this article we study the Gevrey regularization effect for the spatially inhomogeneous Boltzmann equation without angular cut-off.This equation is partially elliptic in the velocity direction and degenerates in the spatial variable.We consider the nonlinear Cauchy problem for the fluctuation around the Maxwellian distribution and prove that any solution with mild regularity will become smooth in the Gevrey class at positive time with the Gevrey index depending on the angular singularity.Our proof relies on the symbolic calculus for the collision operator and the global subelliptic estimate for the Cauchy problem of the linearized Boltzmann operator.     

Gevrey Class Regularity of a Semigroup Associated with a Nonlinear Korteweg-de Vries Equation

In this paper, the authors consider the Gevrey class regularity of a semigroup associated with a nonlinear Korteweg-de Vries(Kd V for short) equation. By estimating the resolvent of the corresponding linear operator, the authors conclude that the semigroup generated by the linear operator is not analytic but of Gevrey class δ∈( 3/2, ∞) for t 0.     

用非标准离散函数和差商定义新广义函数

在非标准分析框架下，用离散函数定义新广义函数，用差商定义其导数．对Schwartz广义函数以及更广的Gevrey超广义函数，文章证明了广义导数可以用差商表示．此外还给出了此新广义函数和Sobolev理论的关系．     

一维广义Ginzburg-Landau方程解的正则性及线性与非线性Galerkin近似

本文得到了一维广义Ginzburs－Landau方程解的Gevrey类正则性和关于时间的解析性．在此基础上得到线性Galerkin近似和非线性Galerkin近似的收敛性．     

GEVREY REGULARITY FOR SOLUTION OF THE SPATIALLY HOMOGENEOUS LANDAU EQUATION

In this paper, we study the Gevrey class regularity for solutions of the spatially homogeneous Landau equations in the hard potential case and the Maxwellian molecules case.     

具非正则奇异性的偏微分方程的形式解（Ⅱ）

本文研究了具非正则奇异性的一阶全特征型偏微分方程的形式幂级数解.利用待定系数法证明了形式幂级数解的存在唯一性,并给出了其Gevrey类指标的计算公式.     

Inhomogeneous Gevrey classes and ultradistributions

The inhomogeneous Gevrey classes, defined in terms of Fourier transform, are a natural extension of the standard Gevrey classes. We find equivalent characterizations and discuss algebraic and topological properties. We therefore introduce the dual spaces, the inhomogeneous ultradistributions, giving some equivalent definitions and corresponding algebraic and topological properties; in particular, a version of the Paley-Wiener-Schwartz theorem is proved in our framework. Finally, as an important example, the multianisotropic Gevrey classes and ultradistributions are considered.     

Well-posedness of the cauchy problem in gevrey classes for some weakly hyperbolic equations of higher order

This article is devoted to the study of the Cauchy problem in Gevrey classes for some higher order weakly hyperbolic equations with time-dependent coefficients and without lower order terms.     

Propagation des singularités Gevrey pour l’équation de Cauchy-Riemann dégénérée

In this paper we study the degenerate Cauchy-Riemann equation in Gevrey classes. We first prove the local solvability in Gevrey classes of functions and ultra-distributions. Using microlocal techniques with Fourier integral operators of infinite order and microlocal energy estimates, we prove a result of propagation of singularities along one dimensional bicharacteristics.      

Strong unique continuation for higher order elliptic equations with Gevrey coefficients

We address the strong unique continuation problem for higher order elliptic partial differential equations in 2D with Gevrey coefficients. We provide a quantitative estimate of unique continuation (observability estimate) and prove that the solutions satisfy the strong unique continuation property for ranges of the Gevrey exponent strictly including non-analytic Gevrey classes. As an application, we obtain a new upper bound on the Hausdorff length of the nodal sets of solutions with a polynomial dependence on the coefficients.     

On the critical index of Gevrey solvability for some linear partial differential equations

We propose precise estimates of the critical index of Gevrey solvability of some classes of linear partial differential equations with multiple characteristics.

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Sunto Si propongono stime precise dell’indice critico della risolubilità di Gevrey di alcune classi di equazioni lineari differenziali con caratteristiche multiple.

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To the memory of L. Cattabriga

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Research partially supported by a Coordinated Research Project of the University of Cagliari and by INDAM-GNAFA, Italy.     

On the Cauchy problem for finitely degenerate hyperbolic equations of second order

This paper is devoted to the study of the Cauchy problem inC ^∞ and in the Gevrey classes for some second order degenerate hyperbolic equations with time dependent coefficients and lower order terms satisfying a suitable Levi condition.     

Gevrey regularity for the supercritical quasi-geostrophic equation

In this paper, following the techniques of Foias and Temam, we establish suitable Gevrey class regularity of solutions to the supercritical quasi-geostrophic equations in the whole space, with initial data in “critical” Sobolev spaces. Moreover, the Gevrey class that we obtain is “near optimal” and as a corollary, we obtain temporal decay rates of higher order Sobolev norms of the solutions. Unlike the Navier–Stokes or the subcritical quasi-geostrophic equations, the low dissipation poses a difficulty in establishing Gevrey regularity. A new commutator estimate in Gevrey classes, involving the dyadic Littlewood–Paley operators, is established that allow us to exploit the cancellation properties of the equation and circumvent this difficulty.     

Gevrey vectors in involutive tube structures and Gevrey regularity for the solutions of certain classes of semilinear systems

In this work, we introduce the notion of s-Gevrey vectors in locally integrable structures of tube type. Under the hypothesis of analytic hypoellipticity, we study the Gevrey regularity of such vectors and also show how this notion can be applied to the study of the Gevrey regularity of solutions of certain classes of semilinear equations.     

Gevrey函数类和超分布中的Paley—Wiener型定理及其应用

众所周知,Paley-Wiener定理深刻地刻画了具紧支集的无穷可微函数及具紧支集的分布同它们的Fourier-Laplace变换之间的关系,建立了具紧支集的无穷可微函数或分布同指数型整函数之间的关系。正因为如此,Paley-Wiener定理在数学中、特别是在偏微分方程的C~∞理论中起着相当重要的作用。本文在具紧支集的Gevrey函数类及具紧支集的超分布中考虑同样类型的定理,称之为Paley-Wiener型定理。     

Gevrey hypoellipticity and solvability on the multidimensional torus of some classes of linear partial differential operators

Abstract In this paper we consider the problem of global analytic and Gevrey hypoellipticity and solvability for a class of partial differential operators on a torus. We prove that global analytic and Gevrey hypoellipticity and solvability on the torus is equivalent to certain Diophantine approximation properties. Keywords: Global hypoellipticity, Global solvability, Gevrey classes, Diophantine approximation property Mathematics Subject Classification (2000): 35D05, 46E10, 46F05, 58J99