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1.
We study lower bounds on the number of nonzero entries in (0, 1) matrices such that the permanent is always convertible to the determinant by placing?±?signs on matrix entries.  相似文献   

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La successione di elementi di una serie di Fourier derivata di una funzione appartenente alla classe di WienerV p,p>1 (rispettivamente alla classe di Waterman {n β}B V o à quella di ChanturiyaV [n β] per qualsiasi 0<β<1) è sommabile verso (f(x+0)?f(x?0))/π mediante i metodi di Cèsaro di ordine α>1?1/p (α>β).  相似文献   

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As to the acronym NEAR(p), it means "New Exponential Autoregressive Process of order p". The NEAR(p) model is denned by where α0,α1,α2… are non-negative and sum to unity, and the residual sequence{εt} is defined as where q1, q2, … , qp+1 are non-negative and sum to unity, and {Et} is an independent and identically distributed (i.i.d.) sequence of standard exponential variants. Chan showed necessary and sufficient conditions for the existence of a stationary and ergodic NEAR(p) model.  相似文献   

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We consider the Navier–Stokes equations for compressible isentropic flow in the steady three-dimensional case. The pressure and the kinetic energy are estimated uniformly in Lq with being the density. This is an improvement of known estimates in the case Mathematics Subject Classification (2000): 35Q30, 76N10  相似文献   

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Let p ≡ = 3 (mod 4) be a prime, let ?( $\sqrt p $ ) be the length of the period of the expansion of $\sqrt p $ into a continued fraction, and let h(4p) be the class number of the field ?( $\sqrt p $ ). Our main result is as follows. For p > 91, h(4p)=1 if and only if ?( $\sqrt p $ ) > 0.56 $\sqrt p $ L4p(1), where L4p(1) is the corresponding Dirichlet series. The proof is based on studying linear relations between convergents of the expansion of $\sqrt p $ into a continued fraction. Bibliography: 13 titles.  相似文献   

8.
For each p ≥ 1, in closed analytic form, we establish the existence of a unique generalized solution in L p of the mixed problem for the wave equation in the rectangle [0 ≤ x ≤ 1] × [0 ≤ tT] with zero initial conditions and with boundary conditions of the first kind, one of which is homogeneous. Next, we derive necessary conditions for this solution to belong to W p 1 . We present examples showing that these necessary conditions are not sufficient for any p ≥ 1.  相似文献   

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We establish necessary and sufficient conditions on the boundary function under which a generalized solution to the initial-boundary value problem for the wave equation with boundary conditions of the first kind belongs to W p 1 .  相似文献   

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ПустьМ[а, b] — множество вещественных функци йf, измеримых и ограниче нных на отрезке [а, b], иL: M[a, b] → M[a, b] — лин ейный положительный оператор. В статье пол учены оценки погрешностей аппроксимации вL p -нор ме, выраженные в термина х так называемого усредненного локаль ного модуля гладкост и, илиτ-модуля. ПустьL облад ает свойствами: (e i ,i(t):=t i дляi=0,1,2)Le 0 =e 0 ,Le 1 =e 1 ,Le 2 (х)=х 2 +β(х), x∈[a,b] и i)A ≦ min (1, (b-a)2/4) для 1 <p<∞, ii)A ≦ min (e ?1 , (b — a)2) дляр=1 приA:=∥βt8. Тогда выполнены оцен ки: $$\begin{gathered} \left\| {f - Lf} \right\|_p \leqq C\frac{p}{{p - 1}}\tau _2 (f;\sqrt A )_p 1< p< \infty \hfill \\ \left\| {f - Lf} \right\|_1 \leqq C\tau _2 \left( {f;\sqrt {A\ln \frac{1}{A}} } \right)_1 , \hfill \\ \end{gathered} $$ где положительные по стоянныеС не завися т от оператораL, функцииfи параметрар.  相似文献   

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Necessary and sufficient conditions for the Lipschitzian invertibility of the difference map
, wheref: ℝ → ℝ is a continuous function, in the spacesl p (ℤ, ℝ), where 1≤p≤∞, of two-sided numerical sequences are obtained. Translated fromMatematicheskie Zametki, Vol. 68, No. 3, pp. 448–454, September, 2000.  相似文献   

16.
We consider the Cauchy problem for the nonlinear Schrödinger equations $ \begin{array}{l} iu_t + \triangle u \pm |u|^{p-1}u =0, \qquad x \in \mathbb{R}^d, \quad t \in \mathbb{R} \\ u(x,0)= u_0(x), \qquad x \in \mathbb{R}^d \end{array} $ for 1 < p < 1 + 4/d and prove that there is a ${\rho (p ,d) \in (1,2)}We consider the Cauchy problem for the nonlinear Schr?dinger equations
l iut + \triangle u ±|u|p-1u = 0,        x ? \mathbbRd,     t ? \mathbbR u(x,0) = u0(x),        x ? \mathbbRd \begin{array}{l} iu_t + \triangle u \pm |u|^{p-1}u =0, \qquad x \in \mathbb{R}^d, \quad t \in \mathbb{R} \\ u(x,0)= u_0(x), \qquad x \in \mathbb{R}^d \end{array}  相似文献   

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This paper considers the approximation of the Kantorovich–Shepard operators in spaces for . For the Kantorovich–Shepard operators are defined by (1.1). Then
where is a positive number depending only on and , and $$ \varepsilon_{n} =\cases{ n^{-1}, & if \ 2$$ " align="middle" border="0"> ; \cr\nosm n^{-1}\log n, & if \ ; \cr\nosm n^{1-\lambda}, & if \ . \cr} $$  相似文献   

18.
The balance laws of mass, momentum and energy are considered for a pth power Newtonian fluid undergoing one dimensional longitudinal motions. For initial-boundary value problems involving fixed endpoints held at a prescribed temperature or insulated, we prove exponential convergence of solutions to equilibria for generic initial data. The estimates for different boundary conditions are presented in a unified manner by utilising the thermodynamic concept of availability.  相似文献   

19.
J.Simons proved that if a minimal submanifold,M~n in the unit sphere S~(n+p)(1)satisfies,|B|~2相似文献   

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