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1.
We consider solutions of functional-differential equations
in both real and complex variables. We characterize entire solutions g when f is a meromorphic function in the complex plane and a ≠ 0, b, c are constants or polynomials. We also examine questions of existence and uniqueness of the solutions in the real variable
for initial value problems and provide theorems that are valid “in the large”. 相似文献
2.
3.
B. Yousefi 《Rendiconti del Circolo Matematico di Palermo》2000,49(1):115-120
Let
be a sequence of positive numbers and 1 ≤p < ∞. We consider the spacel
P(β) of all power series
such that
. We give a necessary and sufficient condition for a polynomial to be cyclic inl
P(β) and a point to be bounded point evaluation onl
P(β). 相似文献
4.
本文研究了一类矩阵方程组解的秩的范围.利用矩阵的奇异值分解以及Frobenius范数的特征,得到了解的极值秩以及解的通式,并就这些问题的特殊情况进行了讨论,得到了一些结果. 相似文献
5.
本文主要研究以下形式的Hausdorff算子HΦf(x)=∫RnΦ(u1….,un)f(u1x1,…,unxn)du1…dun,其中Φ是Rn上的缓增分布.当n≥2,0
Φ在Hp(Rn)上有界当且仅当Φ≡0.进一步,当n≥2,n/n+1
Φ有合适定义,那么HΦ在Hp(Rn)上有界当且仅当Φ是常数.这些结果都表明Hausdorff算子HΦ在Hp(Rn)上的有界性很复杂.此外,我们将HΦ转化成卷积型算子,得到HΦ在Lebesgue空间上有界的一些新的结果. 相似文献
6.
B. de Malafosse 《Acta Mathematica Hungarica》2009,122(3):217-230
We deal with the sum of sequence spaces. Then we apply these results to characterize matrix transformations mapping between
s
h,l
(λ, μ) = s
α
0((Δ − λI)
h
) + s
β
(c)((Δ − μI)
l
) and s
γ
. Among other things the aim of this paper is to reduce the set (s
h,l
(λ, μ), s
γ
to a set of the form S
τ,γ
.
相似文献
7.
V. Yu. Gubarev 《Siberian Mathematical Journal》2009,50(3):395-404
We take the exterior power ℝ4 ∧ ℝ4 of the space ℝ4, its mth symmetric power V = S
m
(∧2ℝ4) = (ℝ4 ∧ ℝ4) ∨ (ℝ4 ∧ ℝ4) ∨ ... ∨(ℝ4 ∧ ℝ4), and put V
0 = L((x ∧ y)∨ ... ∨(x ∧ y): x, y ∈ ℝ4). We find the dimension of V
0 and an algorithm for distinguishing a basis for V
0 efficiently. This problem arose in vector tomography for the purpose of reconstructing the solenoidal part of a symmetric
tensor field.
Original Russian Text Copyright ? 2009 Gubarev V. Yu.
The author was supported by the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grant
NSh-344.2008.1).
__________
Novosibirsk. Translated from Sibirskiĭ Matematicheskiĭ Zhurnal, Vol. 50, No. 3, pp. 503–514, May–June, 2009. 相似文献
8.
Here we solve two problems presented in paper [9] (C C Tisdell and A Zaidi, Basic qualitative and quantitative results for
solutions to nonlinear, dynamic equations on time scales with an application to economic modelling, Nonlinear Anal.
68 (2008) 3504–3524). We study existence and uniqueness of solutions for delay systems and first-order dynamic equations of
the form x
Δ = f (t,x,x
σ
) on time scales by using the Banach’s fixed-point theorem. Some examples are presented to illustrate the efficiency of the
proposed results. 相似文献
9.
10.
11.
Pierre Bousquet 《Journal d'Analyse Mathématique》2007,102(1):311-346
We are interested in the location of the singularities of maps u ∈ W
s,p
(S
N
, S
1) when 1 ≤ sp and 1 < sp < 2. To this end, we consider the distributional Jacobian. We show that the range of this operator on W
s,p
(S
N
, S
1) is the closure in W
s−2,p
⋂ W
−1,sp
of the set of N − 2-currents defined as the integration on smooth oriented N − 2-dimensional boundaryless submanifolds. 相似文献
12.
Jianqin Zhou 《Designs, Codes and Cryptography》2011,58(3):279-296
In this paper, we first optimize the structure of the Wei–Xiao–Chen algorithm for the linear complexity of sequences over GF(q) with period N = 2p
n
, where p and q are odd primes, and q is a primitive root modulo p
2. The second, an union cost is proposed, so that an efficient algorithm for computing the k-error linear complexity of a sequence with period 2p
n
over GF(q) is derived, where p and q are odd primes, and q is a primitive root modulo p
2. The third, we give a validity of the proposed algorithm, and also prove that there exists an error sequence e
N
, where the Hamming weight of e
N
is not greater than k, such that the linear complexity of (s + e)
N
reaches the k-error linear complexity c. We also present a numerical example to illustrate the algorithm. Finally, we present the minimum value k for which the k-error linear complexity is strictly less than the linear complexity. 相似文献
13.
Assuming m − 1 < kp < m, we prove that the space C
∞(M, N) of smooth mappings between compact Riemannian manifolds M, N (m = dim M) is dense in the Sobolev space W
k,p
(M, N) if and only if π
m−1(N) = {0}. If π
m−1(N) ≠ {0}, then every mapping in W
k,p
(M, N) can still be approximated by mappings M → N which are smooth except in finitely many points. 相似文献
14.
15.
Let G be a reflexive subspace of the Banach space E and let Lp(I,E) denote the space of all p-Bochner integrable functions on the interval I=[0,1] with values in E, 1p∞. Given any norm N(
,
) on R2, N nondecreasing in each coordinate on the set R2+, we prove that Lp(I,G) is N-simultaneously proximinal in Lp(I,E). Other results are also obtained. 相似文献
16.
Herv Le Ferrand 《Journal of Approximation Theory》1996,86(3):255-269
We deal with the functionz(f(z), f′(z)) wheref(z)=∑i0 aizi, (ai
) with limi→∞ ai+1×ai−1/(ai)2=q. We investigate the convergence of the vector QD algorithm. We give the asymptotic behaviour of the generalized Hankel determinants. A convergence result on the vector orthogonal polynomials is proved. 相似文献
17.
本文研究了N(2,2,0)代数(S,*,△,0)的E-反演半群.利用N(2,2,0)代数的幂等元,弱逆元,中间单位元的性质和同宇关系,得到了N(2,2,0)代数的半群(S,*)构成E-反演半群的条件及元素α的右伴随非零零因子唯一,且为α的弱逆元等结论,这些结果进一步刻画了N(2,2,0)代数的结构. 相似文献
18.
Let E,F be two Banach spaces,B(E,F),B+(E,F),Φ(E,F),SΦ(E,F) and R(E,F) be bounded linear,double splitting,Fredholm,semi-Frdholm and finite rank operators from E into F,respectively. Let Σ be any one of the following sets:{T ∈Φ(E,F):Index T=constant and dim N(T)=constant},{T ∈ SΦ(E,F):either dim N(T)=constant< ∞ or codim R(T)=constant< ∞} and {T ∈ R(E,F):Rank T=constant< ∞}. Then it is known that Σ is a smooth submanifold of B(E,F) with the tangent space TAΣ={B ∈ B(E,F):BN(A)-R(A) } for any A ∈Σ. However,for ... 相似文献
19.
Barvinok 《Foundations of Computational Mathematics》2008,2(4):393-412
Abstract. Let G be a compact group acting in a real vector space V . We obtain a number of inequalities relating the L
∞ norm of a matrix element of the representation of G with its L
2k
norm for a positive integer k . As an application, we obtain approximation algorithms to find the maximum absolute value of a given multivariate polynomial
over the unit sphere (in which case G is the orthogonal group) and for the assignment problem of degree d , a hard problem of combinatorial optimization generalizing the quadratic assignment problem (in which case G is the symmetric group). 相似文献
20.
S. Yu. Antonov 《Russian Mathematics (Iz VUZ)》2012,56(5):9-22
We estimate the least degree of identities of subspaces M
1(m,k) (F) of the matrix superalgebra M
(m,k)(F) over the field F for arbitrary m and k. For subspaces M
1(m,1) (F) (m≥1) and M
1(2,2) (F) we obtain concrete minimal identities. 相似文献