关于函数S(x)及S*(x)的渐近性质

对于任意实数x∈(1,∞),定义S(x)=min{m∈Nx≤m!};x∈[1,∞),S*(x)=max{m∈Nm!≤x}.主要目的是研究这两个函数的渐近性质,并给出了它们的渐近公式.     

关于函数S(x)及S_*(x)的渐近性质

对于任意实数x∈(1,∞),定义S(x)=m in{m∈N∶x m!};x∈[1,∞),S*(x)=m ax{m∈N∶m!x}.主要目的是研究这两个函数的渐近性质,并给出了它们的渐近公式.     

Continuability,boundness and asymptotic behavior of solutions ofx″ +q(t)f(x)=r(t)

Summary In addition to obtaining sufficient conditions for continuability of solutions of x″ + q(t)f(x)=r(t), some sufficient conditions and some necessary and sufficient conditions for boundedness are obtained. The asymptotic behavior of solutions is studied through examination of r(t)/q(t) as t → ∞. Supported by Mississippi State University Biological and Physical Sciences Research Institute. Entrata in Redazione il 6 febbraio 1973.     

On some properties of solutions of Navier-Stokes equations with oscillating data

We prove statements on asymptotic estimates of solutions of nonstationary Navier-Stokes equations with periodic data rapidly oscillating with respect to the spatial variables when the oscillations are zero in mean. A viscosity coefficient is also considered as a positive parameter in the equations. In the general case, the proved estimates are realistic whenever the viscosity coefficient is not too small in comparison with some power of the parameter specifying the period of data oscillations. In particular, such estimates are valid for Kolmogorov flow with Reynolds number not too large. We formulate conditions under which the asymptotics for velocity fields can contain rapidly oscillating terms. __________ Translated from Trudy Seminara imeni I. G. Petrovskogo, No. 26, pp. 309–322, 2007.     

On asymptotic properties of solutions of functional differential equations of neutral type

In this paper, we obtain sharp estimates for strong solutions of functional differential equations of neutral type. Our result is closely connected with our previous results devoted to the initial-value problem for above-mentioned equations in the scale of Sobolev spaces. To obtain our estimates of the solutions, we essentially use Riesz basis properties of the system of exponential solutions. The fact that they form a Riesz basis is one of the main results of this article. __________ Translated from Sovremennaya Matematika. Fundamental’nye Napravleniya (Contemporary Mathematics. Fundamental Directions), Vol. 15, Differential and Functional Differential Equations. Part 1, 2006.     

Analytic solutions of the Navier-Stokes equations

We consider the time dependent incompressible Navier-Stokes equations on an half plane. For analytic initial data, existence and uniqueness of the solution are proved using the Abstract Cauchy-Kovalevskaya Theorem in Banach spaces. The time interval of existence is proved to be independent of the viscosity.     

On the regularity of the axisymmetric solutions of the Navier-Stokes equations

We obtain improved regularity criteria for the axisymmetric weak solutions of the three dimensional Navier-Stokes equations with nonzero swirl. In particular we prove that the integrability of single component of vorticity or velocity fields, in terms of norms with zero scaling dimension give sufficient conditions for the regularity of weak solutions. To obtain these criteria we derive new a priori estimates for the axisymmetric smooth solutions of the Navier-Stokes equations. Received: 11 April 2000; in final firm: 26 November 2000 / Published online: 28 February 2002     

On partial regularity for weak solutions to the Navier-Stokes equations

In this paper, we study the partial regularity of the general weak solution u∈L∞(0,T;L2(Ω))∩L2(0,T;H1(Ω)) to the Navier-Stokes equations, which include the well-known Leray-Hopf weak solutions. It is shown that there is a absolute constant ε such that for the weak solution u, if either the scaled local L^q(1?q?2) norm of the gradient of the solution, or the scaled local ) norm of u is less than ε, then u is locally bounded. This implies that the one-dimensional Hausdorff measure is zero for the possible singular point set, which extends the corresponding result due to Caffarelli et al. (Comm. Pure Appl. Math. 35 (1982) 717) to more general weak solution.