共查询到20条相似文献,搜索用时 296 毫秒
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设{W(t),t≥0}是一标准Wiener过程,记S是Strassen重对数律的紧集类·本文中我们讨论了两个变量sup0≤t≤1-h inff∈S sup0≤x≤1 |(W(t+hx)-W(t))(2h log h-1)-1/2 - f(x)|及inf0≤t≤1-h sup0≤x≤1 |(W(t + hx) - W(t))(2hlogh-1)-1/2- f(x)|(对任何f∈S)趋于零的精确的收敛速度.作为一个推广,我们建立了Wiener过程的不可微模与泛函的连续模之间的一种关系. 相似文献
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本文研究下列n阶RFDE边值问题:x(n)(t)=f(t,xt,x(t),x′(t),…,x(n-1)(t)), t∈[0,T ],x(t)=φ(t),t∈[-r,0];x′(0)=η,x″(0)=η2,…,x(n-2) (0)=ηn-2,x(j)(T)=A,其中j∈I={0,1,2,…,n-1},得到了解的存在性和唯一性新的结果. 相似文献
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In this paper it is proved that local fundamental solution exists in some space Wm(Hn) (m∈Z), if the left invariant differential operator on the Heisenberg group Hn satisfies certain condition. The main results are:l.Let L be a left invariant differential operator on Hn. If there exist R≥0, r,s∈R and operators {Bλ|λ∈ΓR} ∈Vs(ΓR, Mr) such that, for almost all λ∈ΓR, Bλ is the right inverse of Ⅱλ(L), then there exists E∈Wm(Hn) (when m≥0 or m even) or E∈Wm-1(Hn) (when m<0 and odd) such that LE =δ(near the origie) Where m=min([r],-[2s]-n-2); 2. Let L(W,T) be of the form (3.1). If there exist R≥0 and r,s∈R such that when |λ|≥R,(?) and Cλ≥ C|λ|x(C>0), then the same conclusion as above holds with m=min(-[2r]-n-2,[-2s]-n-2). 相似文献
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多元Szász—Mirkjan算子的一致逼近 总被引:2,自引:0,他引:2
本文研究了多元Szása—Mirakjan算子在C2B(T)中的逼近性质,利用K—泛函,建立了等价的逼近定理.主要结果如下 定理设f∈C2B(T),0a) ;(ii)‖Sn,m(f)-f‖∞ =0(n-a);(iii)a)‖f(x+tφ(x),y)-2f(x,y)+f(x-tφ(x),y)‖∞ =0(t< 相似文献
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具有正负系数的中立型方程的振动性 总被引:7,自引:0,他引:7
讨论中立型方程d/dt[x(t)-R(t)x(t-r)] P(t)x(t-t)-Q(t)x(t-δ)=0,(*)其中P,Q,R∈C[(to,∞),R∧ ),r,τ,δ∈(0,∞),τ≥δ,在允许R(t) ∫∧tt=τ δQ(u)du-1变号的情况下得到(*)的所有解振动的判据。 相似文献
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假设 β1 > 3α1 > 0, β2 > 3α2 > 0,给定函数f(x) ∈ S(R3), 定义算子Tα,β如下:Tα,βf(x,y,z) = p.v.ZTQ2f(x- t, y-s, z-γ(t)h(s)) e-2πit-β1 s-β2/t1+α1 s1+α2dtds.本文主要考虑如上定义的算子Tα,β在Lebesgue空间Lp(R3)及Wiener共合空间W(FLp, Lq)(R3)上的有界性. 这里 Q2 = [0, 1] × [0, 1], γ(t), h(s)满足适当的条件.作为应用, 本文还考虑了带粗糙核的奇异积分算子在乘积空间上的有界性. 相似文献
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Let f(x) be a periodic function of period 2π,|f(x)|and |f(x)|p integrable on [0,2π].It is said to be f∈HX1,if (∫02π|f(x+h)-f(x)|pdx)1/p≤|h|.It is said to be f∈HX2,if (∫02π|f(x+h)+f(x-h)-2f(x)|pdx)1/p≤2|h|. 相似文献
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关于控制算子的若干注记 总被引:1,自引:0,他引:1
Let B(H) be the set of all bounded linear operators on a Hilbert space H. An operator T∈B(H) is called dominant if (T-λ)(T-λ)*≤Mλ2(T-λ)*(T-λ),?λ∈C.The numerical range of T is difined by W (T) = {(Tx, x): ‖x‖ = 1, x∈H}. In Section 1 some new characteristic of dominant operators are given. If C = AB - BA, we prove that O∈W(C)- then A is a dominart or φ-quasihy ponor-mal. In Section 2 we prove that O∈σe(△Aσ) if A is a dominant, where(?), we also prove that if A∈B(H) is a norm attaining Ф-quasihyponormal, then A has a non-trivial invariant subspace. In Section 3 we discuss the closeness of the range of bounded linear operator FAB:X→AX-XB, and prove that R(δA)∩{A}′∩{An}′=0, where δA:X→AX-XA. 相似文献
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Let (θ1,X1),…, (θn,Xn), (θ, X) be iid random vectors ,where θ∈{0,1},X∈Rd Denote by θ′n the nearest neighbour discriminator of θ based on the training samples (θ1,X1),…, (θn,Xn) and the observed X; put(?). This paper gives a sufficient and necessary condition for (?) as n→∞, namely (P(θ=0, X=x)-P(θ=1, X=x))2·P(θ=0, X=x)·P(θ=1, X=x)=0 for every x∈Rd.This generalizes a previous result of the authors [5] and improves a result of Wagner, T.J. [2]. 相似文献
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一类中立型高维周期微分系统的周期解 总被引:10,自引:1,他引:9
本文考虑中立型高维周期系统:其中(L,x)∈R×R~n,A(t,x)为连续函数矩阵,x_t∈C([-γ,0],R~n),x_t(θ)=x(t十θ),θ∈[-r,0],记C=C([-r,0],R~n),f:R×C→R~n连续,且A(t+T,X)=A(t,x),T,r>c∈R,本文用不动点方法研究此系统,得到了其周期解存在的充分性条件,所得结果推广、改进了文[1-3]中相应结论. 相似文献
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一个山路引理的应用 总被引:5,自引:0,他引:5
本文主要考虑如下形式的Dirichlet问题-△u(x)=f(x,u),x∈Ω,∈H01(Ω),其中f(x,t)∈C(Ω×R),f(x,t)/t关于t单调不减,并且当t∈R时关于x∈Ω一致趋向于某个L∞函数q(x)(此时,称f(x,t)关于t在无穷远处是渐近线性的).显然,在该条件下常用的Ambrosetti-Rabinowitz型条件,即关于所有的|s|>M和x∈Ω,0<θF(x,s)2,M>0为常数, F(x,s)=∫0s f(x,t)dt. 众所周知,条件(AR)在山路引理的应用中起着非常重要的作用.本文通过应用一种改进了的山路引理在没有条件(AR)的情况下来证明上面Dirichlet问题(P)也有正解存在。此方法也适用于f(x,t)关于t在无穷远处是超线性,即q(x)≡+∞的情形. 相似文献
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本文考虑 Lienard方程 x″+f (x) x′+g(x) =e(t) ,我们得到 :当 -∞ 0且 0 相似文献
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步尚全 《数学物理学报(B辑英文版)》2011,31(3):765-777
We study Hlder continuous solutions for the second order integro-differential equations with infinite delay (P1): u′′(t)+cu′(t)+∫t-∞β(t-s)u′(s)ds+∫t-∞γ(t-s)u(s)ds = Au(t)-∫t-∞δ(t-s)Au(s)ds + f(t)on the line R, where 0 < α < 1, A is a closed operator in a complex Banach space X, c ∈ C is a constant, f ∈ Cα(R,X) and β,γ,δ∈L1(R+).Under suitable assumptions on the kernels β, γ and δ, we completely characterize the Cα- well-posedness of (P1) by using operator-valued Cα-Fourier multipliers. 相似文献
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GLOBAL CLASSICAL SOLUTIONS TO QUASILINEAR HYPERBOLIC SYSTEMS WITH WEAK LINEAR DEGENERACY 总被引:10,自引:1,他引:9 下载免费PDF全文
ZHOU Yi 《数学年刊B辑(英文版)》2004,25(1):37-56
§1. Introduction and Main Results Consider the following ?rst order quasilinear strictly hyperbolic system ?u ?u A(u) = 0, (1.1) ?t ?xwhere u = (u1, ···,un)T is the unknown vector function of (t,x) and A(u) is an n×n matrixwith suitably smooth elements aij(u) (i,j = 1, ···,n). By the de?nition … 相似文献
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给定实数λ,α以及R上(以λ,α为参数)的压缩自相似映射S1(x)=λx, S2(x)= λx+a, S3(x)= λx+3,记满足测度方程v=(1/3)∑i=1voSi-1的唯一概率测度为uλ,α本文得到:(1)当固定 λ∈A E(1/3, 2/5)时,则在 Lebesgue测度意义下,对于 a.e.的 a∈(0,1),测度 uλ,α绝对连续,且存在平方可积密度.(2)若λ-1是 P.V.数,且 α是λ的有理系数多项式,则测度uλ,α是奇异测度. 相似文献
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Generalized Solution of the First Boundary Value Problem for Parabolic Monge-Ampere Equation 下载免费PDF全文
The existence and uniqueness of generalized solution to the first boundary value problem for parabolic Monge-Ampère equation - ut det D²_xu = f in Q = Ω × (0, T], u = φ on ∂_pQ are proved if there exists a strict generalized supersolution u_φ, where Ω ⊂ R^n is a bounded convex set, f is a nonnegative bounded measurable function defined on Q, φ ∈ C(∂_pQ), φ(x, 0) is a convex function in \overline{\Omega}, ∀x_0 ∈ ∂Ω, φ(x_0, t) ∈ C^α([0, T]). 相似文献