广义控制系统在两种尺度意义下的稳定性

本文将两尺度稳定性理论引入了广义控制系统，并用类Ｌｉａｐｕｎｏｖ函数给出稳定和渐近稳定的充要条件。这些准则推广了关于广义控制系统和两尺度稳定性的已有结果，使我们能在一个统一的框架内研究广义控制系统稳定性。     

Weakly compact operators on function spaces

S — E, F — . C(S, E) S E. : C(S, E) F C(S) . , C(S, E) C(S).     

A-调和方程弱解的双权Caccioppoli型不等式

研究形如div A(x,u(x))=0的A-调和方程,证明了其弱解满足局部Aλr双权Caccioppoli型不等式.其中算子A:Ω×Rn→Rn满足如下条件:对于正常数0   

非齐次A-调和方程弱解的局部极值原理

研究非齐次A-调和方程divA(x,▽u(x))=B(x,▽u(x)),其满足〈A(x,h),h〉≥α|h|~p,|A(x,h)|≤β|h|~(p-1)+g(x),|B(x,h)|≤γ|h|~(p-1).应用Moser迭代法证明其弱解满足局部极值原理,并进一步得出弱解的内部估计和全局估计.     

On the summability of Fourier series with the method of lacunary arithmetic means

. f- ,S _n (f)— . {n _k }, n _k+1/n _k >1+ck ^– ,— , 0<1/2, f ₀, .     

Blow-up of solutions of nonlinear wave equations in three space dimensions

Let u(x,t) be a solution, uA|u|^p for xIR₃, t0 where is the d'Alembertian, and A, p are constants with A>0, 10–|x–x⁰|, if the initial data u(x,0), u_t(x,0) have their support in the ball |x–x⁰|t₀. In particular global solutions of u=A|u|^p with initial data of compact support vanish identically. On the other hand for A>0, p>1+2 global solutions of u=A|u|^p exist, if the initial data are of compact support and u is sufficiently small in a suitable norm. For p=2 the time at which u becomes infinite is of order u^–2.Dedicated to Hans Lewy and Charles B. Morrey, Jr.The research for this paper was performed at the Courant Institute and supported by the Office of Naval Research under Contract No. N00014-76-C-0301. Reproduction in whole or part is permitted for any purpose of the United States Government.     

275-01275-01275-01Regularity of the spatial derivatives of the solutions to parabolic systems in divergence form

Sunto Si dimostra che, nelle ipotesi: fⁱ L^2,(Q, ^N), 0<< n+2, i=0,1,..., n, uL^2,(Q,^N)H _–T ^*0,1/2() (Q,^N), D_iuL^2,(Q,^N),i=1,2,...,n, la soluzione v: Q ^N del problema di Cauchy-Dirichlet: ha derivate spaziali D_iv appartenenti a L^2,(Q,^N) e che sussiste la maggiorazione:.

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Lavoro eseguito con contributo finanziario del M.U.R.S.T. e nell'ambito del G.N.A.F.A. del C.N.R.     

LIPSCHITZ SEMISTABILITY OF GENERAL CONTROL SYSTEMS IN TERMS OF TWO MEASURES

1 IntroductionLipschitz semistability of dynamical systems in terms of two measures andLipschitz semistability of general control systems have already been,t.di.d[llt12].In this papers semistability considerations will be extended to a variety of nonlinear systems utilizing the same versatile tools, namely, Liapunov--like functions. The notions of (ho, h)-Lipschitz (weak) semistability of general controlsystems are introduced, and the necessary and sufficient conditions are given.2 Prelimina…     

A two‐level queueing network model with blocking and non‐blocking messages

We analyze a novel twolevel queueing network with blocking, consisting of N level1 parallel queues linked to M level2 parallel queues. The processing of a customer by a level1 server requires additional services that are exclusively offered by level2 servers. These level2 servers are accessed through blocking and nonblocking messages issued by level1 servers. If a blocking message is issued, the level1 server gets blocked until the message is fully processed at the level2 server. The queueing network is analyzed approximately using a decomposition method, which can be viewed as a generalization of the wellknown twonode decomposition algorithm used to analyze tandem queueing networks with blocking. Numerical tests show that the algorithm has a good accuracy.     

Bivariate distributions with Weibull conditionals

, . , - . , , , .     

动力系统在两种尺度意义下的Lipschitz半稳定性

本文将半稳定性（即在某种限制条件下的稳定性）和Ｌｉｐｓｃｈｉｔｚ稳定性,两尺度稳定性概念结合,提出动力系统的（ｈ０,ｈ）－半稳定和（ｈ０,ｈ）－Ｌｉｐｓｃｈｉｔｚ（局部）半稳定性概念,并且Ｌｉａｐｕｎｏ类似函数给出相应的充要条件。     

关于（k,h）-Fibonacci和（k,h）-Lucas数的置换因子循环矩阵的谱范数

给出了置换因子循环矩阵A=Percirc P（F_0^（k,h）,F_1^（k,h）,＊＊＊,F_n-1^（k,h）和B=Percirc P（L_0^（k,h）,L_1^（k,h）,＊＊＊,L_n-1^（k,h）的谱范数的上界与下界,得到了矩阵A与B的Kronecker积与Hadamard积的谱范数的一些界．     

Quadrilaterals,extremal quasiconformal extensions and Hamilton sequences

The relationship between Strebel boundary dilatation of a quasisymmetric function h of the unit circle and the dilatation indicated by the change in the modules of the quadrilaterals with vertices on the circle intrigues many mathematicians. It had been a conjecture for some time that the dilatations Ko（h） and K1（h） of h are equal before Anderson and Hinkkanen disproved this by constructing concrete counterexamples. The independent work of Wu and of Yang completely characterizes the condition for Ko（h） = K1 （h） when h has no substantial boundary point. In this paper, we give a necessary and sufficient condition to determine the equality for h admitting a substantial boundary point.     

Subgroups of the full linear group over a Dedekind ring

We study the subgroups of the full linear group GL(n, R) over a Dedekind ring R that contain the group of quasidiagonal matrices of fixed type with diagonal blocks of at least third order, each of which is generated by elementary matrices. For any such subgroup H there exists a unique D-net of ideals of R such that, where E() is the subgroup generated by all transvections of the net subgroup G(). and is the normalizer of G(). The subgroup E() is normal in. To study the factor group we introduce an intermediate subgroup F(), E() F() G(). The group is finite and is connected with permutations in the symmetric group. The factor group G()/F() is Abelian — these are the values of a certain determinant. In the calculation of F()/E() appears the SK₁-functor. Results are stated without proof.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 94, pp. 13–20, 1979.     

Imbedding problem with non-Abelian kernel of order p4

This paper considers the imbedding problem for numerical fields and p-groups with nonabelian kernel of order p⁴, two generators and , and defining relations =1, ^p=1, [,,]=1, and [,,]= 1. For p=2 and almost always for odd p, the Hasse principle is valid, and the problem is solvable if and only if all related local problems are solvable. Counterexamples in which the Hasse principle is not valid are constructed for some exceptional cases.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 175, pp. 46–62, 1989.     

Hulls for Various Kinds of α-Completeness in Archimedean Lattice-Ordered Groups

Within Archimedean -groups, and with an infinite cardinal or , we consider X-hulls where X stands for any of the following classes of -groups: -projectable; laterally -complete; boundedly laterally -complete; conditionally -complete; combinations of the preceding, together with divisibility and/or relative uniform completeness. All these hulls exist, and may be obtained by iterated adjunction of the required extra elements, within the essential hull. When the -groups is relatively -complemented one step in the iteration suffices for several crucial properties. We derive from the above a considerable number of equations involving combinations of these hull operators.     

特征值问题混合有限元法的一个误差估计

设（λh,σh,uh）是一个混合有限元特征对.Babuska和Osborn建立了（λh,uh）的误差估计.本文导出了σh的抽象误差估计式.并把该估计式应用于二阶椭圆特征值问题Raviart-Thomas混合有限元格式和重调和算子特征值问题Ciarlet-Raviart混合有限元格式,得到了一些新的误差估计.     

Asymptotic behaviour of the solution of a semilinear parabolic equation

We study the asymptotic behaviour ast tends to + of the solution of (u/t)–Lu+(u)–0,u _|=0 whereL is a second order self-adjoint elliptic operator and a maximal monotone graph of . If |(r)|/|r|²L ¹ (-1, 1) and ₁ is the first eigenvalue ofL we prove that u(.,t) converges uniformly on to some element of Ker (L + ₁ I) and that the limit is nonzero if |(r)|/|r| is nondecreasing. We give also some properties of the limit (monotonicity, continuity, range).     

LIPSCHITZ STABILITY OF GENERAL CONTROL SYSTEMS Ⅱ.IN TERMS OF TWO MEASURES

1IntroductionStabilityintermsoftwomeasures,thisconceptenableustounifyava-rietyofstabilityconceptsandtoofferageneralandunifiedframeworkforinvestigationofstabilitytheory.AndtheoriginalLiapunovtheoremshavebeenextended,generalizedandweakenedinvariousaspects[3…     

Partly convex programming and zermelo's navigation problems

Mathematical programs, that become convex programs after freezing some variables, are termed partly convex. For such programs we give saddle-point conditions that are both necessary and sufficient that a feasible point be globally optimal. The conditions require cooperation of the feasible point tested for optimality, an assumption implied by lower semicontinuity of the feasible set mapping. The characterizations are simplified if certain point-to-set mappings satisfy a sandwich condition.The tools of parametric optimization and basic point-to-set topology are used in formulating both optimality conditions and numerical methods. In particular, we solve a large class of Zermelo's navigation problems and establish global optimality of the numerical solutions.Research partly supported by NSERC of Canada.