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1.
Let G be a simple graph with n vertices and m edges. Let λ1, λ2,…, λn, be the adjacency spectrum of G, and let μ1, μ2,…, μn be the Laplacian spectrum of G. The energy of G is E(G) = n∑i=1|λi|, while the Laplacian energy of G is defined as LE(G) = n∑i=1|μi-2m/n| Let γ1, γ2, ~ …, γn be the eigenvalues of Hermite matrix A. The energy of Hermite matrix as HE(A) = n∑i=1|γi-tr(A)/n| is defined and investigated in this paper. It is a natural generalization of E(G) and LE(G). Thus all properties about energy in unity can be handled by HE(A).  相似文献   

2.
An m-cycle system of order v and index λ, denoted by m-CS(v,λ), is a collection of cycles of length m whose edges partition the edges of λKv. An m-CS(v,λ) is α-resolvable if its cycles can be partitioned into classes such that each point of the design occurs in precisely α cycles in each class. The necessary conditions for the existence of such a design are m|λv(v-1)/2,2|λ(v -1),m|αv,α|λ(v-1)/2. It is shown in this paper that these conditions are also sufficient when m = 4.  相似文献   

3.
The authors consider the well-posedness in energy space of the critical non-linear system of wave equations with Hamiltonian structure{utt-△u=-F1(|u|^2,|v|^2)u,utt-△u=-F2(|u|^2,|v|^2)u where there exists a function F(λ,μ) such that δF(λ,μ)/δλ=F1(λ,μ).δF(λ,μ)/δμ=F2(λ,μ) By showing that the energy and dilation identities hold for weak solution under some assumptions on the non-linearities, we prove the global well-posedness in energy space by a similar argument to that for global regularity as shown in "Shatah and Struwe's paper, Ann. of Math. 138, 503-518 (1993)".  相似文献   

4.
The Cauchy problem for a linear 2mth-order Schrōdinger equation ut=-i(-△)^mu, in R^N×R+,u|t=0=u0;m≥1 is an integer,is studied, for initial data uo in the weighted space L^2ρ(R^N),withρ^*(x)=e|x|^a and a=2m/2m-1∈(1,2].The following five problems are studied: (I) A sharp asymptotic behaviour of solutions as t → +∞ is governed by a discrete spectrum and a countable set Ф of the eigenfunctions of the linear rescaled operator B=-i(-△)^m+1/2my·↓△+N/2mI,with the spectrum σ(B)={λβ=-|β|≥0}. (Ⅱ) Finite-time blow-up local structures of nodal sets of solutions as t → 0^- and a formation of "multiple zeros" are described by the eigenfunctions, being generalized Hermite polynomials, of the "adjoint" operator B=-i(-△)^m-1/2my·↓△,with the same spectrum σ(B^*)=σ(B).Applications of these spectral results also include: (Ⅲ) a unique continuation theorem, and (IV) boundary characteristic point regularity issues. Some applications are discussed for more general linear PDEs and for the nonlinear Schr6dinger equations in the focusing ("+") and defocusing ("-") cases ut=-(-△)^mu±i|u|^p-1u,in R^N×R+,where P〉1,as well as for: (V) the quasilinear Schr6dinger equation of a "porous medium type" ut=-(-△)^m(|u|^nu),in R^N×R+,where n〉0.For the latter one, the main idea towards countable families of nonlinear eigenfunctions is to perform a homotopic path n → 0^+ and to use spectral theory of the pair {B,B^*}.  相似文献   

5.
Let Ω be a bounded domain with a smooth C2 boundary in RN(N ≥ 3), 0 ∈Ω, and n denote the unit outward normal to ЭΩ.We are concerned with the Neumann boundary problems: -div(|x|α|△u|p-2△u)=|x|βup(α,β)-1-λ|x|γup-1,u(x)〉0,x∈Ω,Эu/Эn=0 on ЭΩ,where 1〈p〈N and α〈0,β〈0 such that p(α,β)△=p(N+β)/N-p+α〉p,y〉α-p.For various parameters α,βorγ,we establish certain existence results of the solutions in the case 0∈Ω or 0∈ЭΩ.  相似文献   

6.
In this work, we are interested to obtain some result of existence and nonex- istence of positive weak solution for the following p-Laplacian system
{-△piui=λifi(u1,^…,um),inΩ, i=1,...,m, ui=0,
on δΩ,Vi=1,…,m,
where △piz = div(|△z|^pi-2△Z), Pi ≥ 1,λi,1 ≤ i ≤ m are a positive parameter, and Ω is a bounded domain in IR^N with smooth boundary δΩ. The proof of the main results is based to the method of sub-supersolutions.  相似文献   

7.
Values of new series sum(((2n-1)!ζ(2n))/(2n + 2k)!)α2n from n=1 to ∞,sum(((2n-1)!ζ(2n))/(2n+2k +1)!)β2n from n=1 to ∞ are given concerning ζ(2k + 1),where k is a positive integer,α can be taken as 1,1/2,1/3,2/3,1/4,3/4,1/6,5/6 and β can be taken as 1,1/2.Some previous results are included as special cases in the present paper and new series converges more rapidly than those exsiting results for α = 1/3,or α = 1/4,or α = 1/6.  相似文献   

8.
For positive integers j and k with j ≥ k, an L(j, k)-labeling of a graph G is an assignment of nonnegative integers to V(G) such that the difference between labels of adjacent vertices is at least j, and the difference between labels of vertices that are distance two apart is at least k. The span of an L(j, k)-labeling of a graph G is the difference between the maximum and minimum integers it uses. The λj, k-number of G is the minimum span taken over all L(j, k)-labelings of G. An m-(j, k)-circular labeling of a graph G is a function f : V(G) →{0, 1, 2,..., m - 1} such that |f(u) - f(v)|m ≥ j if u and v are adjacent; and |f(u) - f(v)|m 〉 k ifu and v are at distance two, where |x|m = min{|xl|, m-|x|}. The minimum integer m such that there exists an m-(j, k)-circular labeling of G is called the σj,k-number of G and is denoted by σj,k(G). This paper determines the σ2,1-number of the Cartesian product of any three complete graphs.  相似文献   

9.
Let {Xni} be an array of rowwise negatively associated random variables and Tnk=k∑i=1 i^a Xni for a ≥ -1, Snk =∑|i|≤k Ф(i/nη)1/nη Xni for η∈(0,1],where Ф is some function. The author studies necessary and sufficient conditions of ∞∑n=1 AnP(max 1≤k≤n|Tnk|〉εBn)〈∞ and ∞∑n=1 CnP(max 0≤k≤mn|Snk|〉εDn)〈∞ for all ε 〉 0, where An, Bn, Cn and Dn are some positive constants, mn ∈ N with mn /nη →∞. The results of Lanzinger and Stadtmfiller in 2003 are extended from the i.i.d, case to the case of the negatively associated, not necessarily identically distributed random variables. Also, the result of Pruss in 2003 on independent variables reduces to a special case of the present paper; furthermore, the necessity part of his result is complemented.  相似文献   

10.
王建飞  刘太顺 《数学季刊》2007,22(2):159-165
Bohr's type inequalities are studied in this paper: if f is a holomorphic mapping from the unit ball B^n to B^n, f(0)=p, then we have sum from k=0 to∞|DφP(P)[D^kf(0)(z^k)]|/k!||DφP(P)||〈1 for|z|〈max{1/2+|P|,(1-|p|)/2^1/2andφ_P ∈Aut(B^n) such thatφ_(p)=0. As corollaries of the above estimate, we obtain some sharp Bohr's type modulus inequalities. In particular, when n=1 and |P|→1, then our theorem reduces to a classical result of Bohr.  相似文献   

11.
A Littlewood-Paley type inequality   总被引:2,自引:0,他引:2  
In this note we prove the following theorem: Let u be a harmonic function in the unit ball and . Then there is a constant C = C(p, n) such that
.  相似文献   

12.
We establish conditions for the existence and uniqueness of a generalized solution of the Cauchy problem for the equation
in a Tikhonov-type class. Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 5, pp. 586–602, May, 2008.  相似文献   

13.
Let {X,Xn;n ≥ 1} be a strictly stationary sequence of ρ-mixing random variables with mean zeros and finite variances. Set Sn =∑k=1^n Xk, Mn=maxk≤n|Sk|,n≥1.Suppose limn→∞ESn^2/n=:σ^2〉0 and ∑n^∞=1 ρ^2/d(2^n)〈∞,where d=2 if 1≤r〈2 and d〉r if r≥2.We prove that if E|X|^r 〈∞,for 1≤p〈2 and r〉p,then limε→0ε^2(r-p)/2-p ∑∞n=1 n^r/p-2 P{Mn≥εn^1/p}=2p/r-p ∑∞k=1(-1)^k/(2k+1)^2(r-p)/(2-p)E|Z|^2(r-p)/2-p,where Z has a normal distribution with mean 0 and variance σ^2.  相似文献   

14.
  A theorem from the classical complex analysis proved by Davydov in 1949 is extended to the theory of solution of a special case of the Beltrami equation in the z-complex plane (i.e., null solutions of the differential operator ). It is proved that if γ is a rectifiable Jordan closed curve and f is a continuous complex-valued function on γ such that the integral
converges uniformly on γ as r → 0, where n(ζ) is the unit vector of outer normal on γ at a point ζ and ds is the differential of arc length, then the β-Cauchy-type integral
admits a continuous extension to γ and a version of the Sokhotski–Plemelj formulas holds. Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 11, pp. 1443–1448, November, 2008.  相似文献   

15.
In this article, we apply the molecular characterization of the weighted Hardy space developed by the first two authors to show the boundedness of Hormander multiplier on the weighted Herz-type Hardy spaces HK^α,p 2(|x|^t; |x|^t) and HK^α,P 2(|x|^t; |x|^t).  相似文献   

16.
In this paper, we discuss the moving-average process Xk = ∑i=-∞ ^∞ ai+kεi, where {εi;-∞ 〈 i 〈 ∞} is a doubly infinite sequence of identically distributed ψ-mixing or negatively associated random variables with mean zeros and finite variances, {ai;-∞ 〈 i 〈 -∞) is an absolutely solutely summable sequence of real numbers.  相似文献   

17.
In this paper, the author proves the existence and uniqueness of nonnegative solution for the first boundary value problem of uniform degenerated parabolic equation $$\[\left\{ {\begin{array}{*{20}{c}} {\frac{{\partial u}}{{\partial t}} = \sum {\frac{\partial }{{\partial {x_i}}}\left( {v(u){A_{ij}}(x,t,u)\frac{{\partial u}}{{\partial {x_j}}}} \right) + \sum {{B_i}(x,t,u)} \frac{{\partial u}}{{\partial {x_i}}}} + C(x,t,u)u\begin{array}{*{20}{c}} {}&{(x,t) \in [0,T]} \end{array},}\{u{|_{t = 0}} = {u_0}(x),x \in \Omega ,}\{u{|_{x \in \partial \Omega }} = \psi (s,t),0 \le t \le T} \end{array}} \right.\]$$ $$\[\left( {\frac{1}{\Lambda }{{\left| \alpha \right|}^2} \le \sum {{A_{ij}}{\alpha _i}{\alpha _j}} \le \Lambda {{\left| \alpha \right|}^2},\forall a \in {R^n},0 < \Lambda < \infty ,v(u) > 0\begin{array}{*{20}{c}} {and}&{v(u) \to 0\begin{array}{*{20}{c}} {as}&{u \to 0} \end{array}} \end{array}} \right)\]$$ under some very weak restrictions, i.e. $\[{A_{ij}}(x,t,r),{B_i}(x,t,r),C(x,t,r),\sum {\frac{{\partial {A_{ij}}}}{{\partial {x_j}}}} ,\sum {\frac{{\partial {B_i}}}{{\partial {x_i}}} \in \overline \Omega } \times [0,T] \times R,\left| {{B_i}} \right| \le \Lambda ,\left| C \right| \le \Lambda ,\],\[\left| {\sum {\frac{{\partial {B_i}}}{{\partial {x_i}}}} } \right| \le \Lambda ,\partial \Omega \in {C^2},v(r) \in C[0,\infty ).v(0) = 0,1 \le \frac{{rv(r)}}{{\int_0^r {v(s)ds} }} \le m,{u_0}(x) \in {C^2}(\overline \Omega ),\psi (s,t) \in {C^\beta }(\partial \Omega \times [0,T]),0 < \beta < 1\],\[{u_0}(s) = \psi (s,0).\]$  相似文献   

18.
We present an equivalent definition of functions analytic in the half-plane ℂ+ = {z: Re z > 0} for which
. Translated from Ukrains'kyi Matematychnyi Zhurnal, Vol. 60, No. 9, pp. 1270–1274, September, 2008.  相似文献   

19.
This paper, by using of windowed Fourier transform (WFT), gives a family of embedding operators Tn:L^2(R)→L^2(C,e^-|z|^2/2dzd-↑z/4πi), s.t. TnL^2(R) lontain in L^2(C,e^-|z|^2/2dzd-↑z/4πi) are reproducing subspaces (n=0, Bargmann Space); and gives a reproducing kernel and an orthonormal basis (ONB) of TnL^2(R), Furthermore, it shows the orthogonal spaces decomposition of L^2(C,e^-|z|^2/2dzd-↑z/4πi). Finally, by using the preceding results, it shows the eigenvalues and eigenfunctions of a class of localization operators associated with WFT, which extends the result of Daubechies in [1] and [6].  相似文献   

20.
Let f be in the localized nonisotropic Sobolev space on the n-dimensional Heisenberg group ℍ n = ℂ n × ℝ, where 1 = p < Q and Q = 2n + 2 is the homogeneous dimension of ℍn. Suppose that the subelliptic gradient is gloablly L p integrable, i.e., is finite. We prove a Poincaré inequality for f on the entire space ℍ n . Using this inequality we prove that the function f subtracting a certain constant is in the nonisotropic Sobolev space formed by the completion of under the norm of
We will also prove that the best constants and extremals for such Poincaré inequalities on ℍ n are the same as those for Sobolev inequalities on ℍ n . Using the results of Jerison and Lee on the sharp constant and extremals for L 2 to Sobolev inequality on the Heisenberg group, we thus arrive at the explicit best constant for the aforementioned Poincaré inequality on ℍ n when p = 2. We also derive the lower bound of the best constants for local Poincaré inequalities over metric balls on the Heisenberg group ℍ n . The first author is supported by Zhongdian grant of NSFC; The second author is supported by a global grant at Wayne State University and by NSF of USA  相似文献   

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