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1.
We prove some new a priori estimates for H 2-convex functions which are zero on the boundary of a bounded smooth domain Ω in a Carnot group . Such estimates are global and are geometric in nature as they involve the horizontal mean curvature of ∂Ω. As a consequence of our bounds we show that if has step two, then for any smooth H 2-convex function in vanishing on ∂Ω one has
. Supported in part by NSF Grant DMS-07010001.  相似文献   

2.
Let Δ(x) denote the error term in the Dirichlet divisor problem, and E(T) the error term in the asymptotic formula for the mean square of . If E *(t)=E(t)-2πΔ*(t/2π) with , then we obtain
and
It is also shown how bounds for moments of | E *(t)| lead to bounds for moments of .  相似文献   

3.
We consider the following semilinear elliptic equation with singular nonlinearity:
where and Ω is an open subset in . Let u be a non-negative finite energy stationary solution and be the rupture set of u. We show that the Hausdorff dimension of Σ is less than or equal to [(n−2) α+(n+2)]/(α +1).  相似文献   

4.
We establish a new bound for the exponential sum
where λ is an element of the residue ring modulo a large prime number
and
are arbitrary subsets of the residue ring modulo p − 1 and γ (n) are any complex numbers with | γ (n)| ≦ 1. Received: 15 June 2005  相似文献   

5.
We consider the following Liouville equation in
For each fixed and a j  > 0 for 1 ≤ jk, we construct a solution to the above equation with the following asymptotic behavior:
  相似文献   

6.
We prove the following statement. Let , and let . Suppose that, for all and , the sequence satisfies the relation
where e(u) : = e2πiu . Then
where q is the set of q-multiplicative functions g such that .  相似文献   

7.
In this paper, we prove that if is a radially symmetric, sign-changing stationary solution of the nonlinear heat equation
in the unit ball of , N ≥ 3, with Dirichlet boundary conditions, then the solution of (NLH) with initial value blows up in finite time if |λ − 1| > 0 is sufficiently small and if α is subcritical and sufficiently close to 4/(N − 2). F. Dickstein was partially supported by CNPq (Brazil).  相似文献   

8.
We characterize the composition operators mapping Blochs boundedly into the weighted Bergman spaces of logarithmic weight. For 0 < p < ∞, 1 < α < ∞, let Ap, log α denote the space of holomorphic functions F in the unit disc D for which
and let Ap, log ασ denote the class of holomorphic self maps f of D for which
Then for the Bloch pullback operator Cf, the following are equivalent:
(1)  Cf maps Bloch space boundedly into A2p, log α
(2) 
(3)  .
This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2007-313-C00026).  相似文献   

9.
Nonimprovable effective sufficient conditions are established for the unique solvability of the periodic problem
where ω  >  0, ℓi : C([0, ω])→ L([0,ω]) are linear bounded operators, and qiL([0, ω]). Received: 11 June 2005  相似文献   

10.
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   

11.
We consider autonomous integrals
in the multidimensional calculus of variations, where the integrand f is a strictly W 1,p -quasiconvex C 2-function satisfying the (p,q)-growth conditions
with exponents 1 < p ≤  q < ∞. Under these assumptions we establish an existence result for minimizers of F in provided . We prove a corresponding partial C 1,α -regularity theorem for . This is the first regularity result for autonomous quasiconvex integrals with (p,q)-growth.  相似文献   

12.
Suppose thatА is a nonnegative self-adjoint extension to { } of the formal differential operator−Δu+q(x)u with potentialq(x) satisfying the condition {
} or the condition {
} in which the nonnegative function itχ(r) is such that { }. For each α∈(0, 2], we establish an estimate of the generalized Fourier transforms of an arbitrary function { } of the form {
} If, in addition, { }, then, along with this estimate, a similar lower bound is established. Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 542–551, April, 1999.  相似文献   

13.
For positive integers with a r  = 2, the multiple zeta value or r-fold Euler sum is defined as [2]
. There is a celebrated sum formula [6, 10] among multiple zeta values as
, where range over all positive integers with in the summation. In this paper, we shall prove the so called restricted sum formula [4]. Namely, for all positive integers m and q with m ≥ q and a nonnegative integer p, that
. We prove the assertion by new expressions of multiple zeta values in terms of Drinfeld integrals. This work was supported by the Department of Mathematics, National Chung Cheng University and by the National Science Council of Taiwan, Republic of China.  相似文献   

14.
Let u=u(x,t,uo)represent the global solution of the initial value problem for the one-dimensional fluid dynamics equation ut-εuxxt+δux+γHuxx+βuxxx+f(u)x=αuxx,u(x,0)=uo(x), whereα〉0,β〉0,γ〉0,δ〉0 andε〉0 are constants.This equation may be viewed as a one-dimensional reduction of n-dimensional incompressible Navier-Stokes equations. The nonlinear function satisfies the conditions f(0)=0,|f(u)|→∞as |u|→∞,and f∈C^1(R),and there exist the following limits Lo=lim sup/u→o f(u)/u^3 and L∞=lim sup/u→∞ f(u)/u^5 Suppose that the initial function u0∈L^I(R)∩H^2(R).By using energy estimates,Fourier transform,Plancherel's identity,upper limit estimate,lower limit estimate and the results of the linear problem vt-εv(xxt)+δvx+γHv(xx)+βv(xxx)=αv(xx),v(x,0)=vo(x), the author justifies the following limits(with sharp rates of decay) lim t→∞[(1+t)^(m+1/2)∫|uxm(x,t)|^2dx]=1/2π(π/2α)^(1/2)m!!/(4α)^m[∫R uo(x)dx]^2, if∫R uo(x)dx≠0, where 0!!=1,1!!=1 and m!!=1·3…(2m-3)…(2m-1).Moreover lim t→∞[(1+t)^(m+3/2)∫R|uxm(x,t)|^2dx]=1/2π(x/2α)^(1/2)(m+1)!!/(4α)^(m+1)[∫Rρo(x)dx]^2, if the initial function uo(x)=ρo′(x),for some functionρo∈C^1(R)∩L^1(R)and∫Rρo(x)dx≠0.  相似文献   

15.
  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   

16.
We use an inequality due to Bochnak and Lojasiewicz, which follows from the Curve Selection Lemma of real algebraic geometry in order to prove that, given a C r function , we have
where . This shows that the so-called Morse decomposition of the critical set, used in the classical proof of the Morse–Sard theorem, is not necessary: the conclusion of the Morse decomposition lemma holds for the whole critical set. We use this result to give a simple proof of the classical Morse–Sard theorem (with sharp differentiability assumptions).  相似文献   

17.
Let λ ∈ (0, 1) and let T be a r × r complex matrix with polar decomposition T = U|T|. Then the λ-Aluthge transform is defined by
. Let denote the n-times iterated Aluthge transform of T, . We prove that the sequence converges for every r × r diagonalizable matrix T. We show regularity results for the two parameter map , and we study for which matrices the map is constant. The first and third author were partially supported by CONICET (PIP 4463/96), Universidad de La Plata (UNLP 11 X472) and ANPCYT (PICT03-09521). The second author was partially supported by CNPq.  相似文献   

18.
Besides other things we prove that if , , locally minimizes the energy
, with N-functions a  ≤ b having the Δ2-property, then . Moreover, the condition
for all large values of t implies . If n = 2, then these results can be improved up to for all s < ∞ without the hypothesis . If n ≥ 3 together with M = 1, then higher integrability for any exponent holds under more restrictive assumptions than .   相似文献   

19.
In this paper, we study certain polylogarithmic double series
where p, q, r are nonnegative integers and x is any complex number with
. First we give certain polylogarithmic interpolation formulas of the results of Mordell, Subbarao-Sitaramachandrarao and Zagier. By specializing to x = 1, we can obtain their results. Secondly we calculate some special values of these polylogarithmic double series. Received: 21 November 2005; Revised: 8 May 2006  相似文献   

20.
A power series with radius of convergence equal 1 is called a (p,A)-lacunary one if nk ≥ Akp, A > 0, 1 < p < ∞. It is proved that if 1 < p < 2 and f(x) is a (p,A)-lacunary series that satisfies the condition
, where
, for some ε > 0, then f ≡ 0. We construct a (p,A)-lacunary series f 0 such that
with a constant C0 = C0(p,A) > 0. Bibliography: 4 titles. __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 327, 2003, pp. 135–149.  相似文献   

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