共查询到20条相似文献,搜索用时 31 毫秒
1.
Elbieta Wagner-Bojakowska Wadysaw Wilczyski 《Rendiconti del Circolo Matematico di Palermo》2000,49(1):5-26
We prove that for an arbitrary setA ⊂ ℝ its interior in aψ-density topology equalsA ∩ φβ(B), whereB is a measurable kernel ofA andβ is some countable ordinal. Moreover, eachβ, 1≤β<Ω, realizes the interior ofA for someA εS. 相似文献
2.
For fixed generalized reflection matrix P, i.e. P
T
= P, P
2 = I, then matrix X is said to be generalized bisymmetric, if X = X
T
= PXP. In this paper, an iterative method is constructed to find the generalized bisymmetric solutions of the matrix equation A
1
X
1
B
1 + A
2
X
2
B
2 + ⋯ + A
l
X
l
B
l
= C where [X
1,X
2, ⋯ ,X
l
] is real matrices group. By this iterative method, the solvability of the matrix equation can be judged automatically. When
the matrix equation is consistent, for any initial generalized bisymmetric matrix group , a generalized bisymmetric solution group can be obtained within finite iteration steps in the absence of roundoff errors,
and the least norm generalized bisymmetric solution group can be obtained by choosing a special kind of initial generalized
bisymmetric matrix group. In addition, the optimal approximation generalized bisymmetric solution group to a given generalized
bisymmetric matrix group in Frobenius norm can be obtained by finding the least norm generalized bisymmetric solution group of the new matrix equation
, where . Given numerical examples show that the algorithm is efficient.
Research supported by: (1) the National Natural Science Foundation of China (10571047) and (10771058), (2) Natural Science
Foundation of Hunan Province (06JJ2053), (3) Scientific Research Fund of Hunan Provincial Education Department(06A017). 相似文献
3.
Let K be a field of characteristic 0 and let p, q, G
0
, G
1
, P ∈K[x], deg P ⩾ 1. Further, let the sequence of polynomials (G
n
(x))
n=0
∞ be defined by the second order linear recurring sequence
In this paper we give conditions under which the diophantine equation G
n
(x) = G
m
(P(x)) has at most exp(1018) many solutions (n, m) ε ℤ2, n, m ⩾ 0. The proof uses a very recent result on S-unit equations over fields of characteristic 0 due to Evertse, Schlickewei and Schmidt [14]. Under the same conditions we
present also bounds for the cardinality of the set
In the last part we specialize our results to certain families of orthogonal polynomials.
This work was supported by the Austrian Science Foundation FWF, grant S8307-MAT.
The second author was supported by the Hungarian National Foundation for Scientific Research Grants No 16741 and 38225.
Received June 5, 2001; in revised form February 26, 2002
RID="a"
ID="a" Dedicated to Edmund Hlawka on the occasion of his 85th birthday 相似文献
4.
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
5.
We prove that if a symmetric submarkovian semigroup (T
t
)
t>0
satisfies an estimate of the form
where ϕ is an increasing C
1
-diffeomorphism of [0,+∞) with subexponential growth, then a suitable function of its infinitesimal generator is bounded from
L
p
(M) to L
q
(M) for 1<p<q<+∞, and that a weak converse holds true if p=2. In the special case where ϕ(t)=Ct
μ
for small t and ϕ(t)=C′ exp(ct
ν
) for large t, μ>0, c>0, 0<ν<1, one obtains a sharp and explicit result, which applies for instance to sublaplacians on solvable unimodular Lie
groups with exponential growth.
Received: 29 June 2001 /
Published online: 1 April 2003
Mathematics Subject Classifications (2000): 47D06, 58J35, 43A80
Research supported by the Italian M.U.R.S.T., fondi 60%, the Italian GNAFA, and the European Commission (European TMR Network
``Harmonic Analysis' 1998–2001, Contract ERBFMRX-CT97-0159). 相似文献
6.
Let K be a field of characteristic 0 and let p, q, G 0 , G 1 , P ∈K[x], deg P ⩾ 1. Further, let the sequence of polynomials (G n (x)) n=0 ∞ be defined by the second order linear recurring sequence
In this paper we give conditions under which the diophantine equation G n (x) = G m (P(x)) has at most exp(1018) many solutions (n, m) ε ℤ2, n, m ⩾ 0. The proof uses a very recent result on S-unit equations over fields of characteristic 0 due to Evertse, Schlickewei and Schmidt [14]. Under the same conditions we present also bounds for the cardinality of the set
相似文献
7.
We consider which ordinals, with the order topology, can be Stone-?ech remainders of which spaces of the form ψ(κ,M), where ω?κ is a cardinal number and M⊂ω[κ] is a maximal almost disjoint family of countable subsets of κ (MADF). The cardinality of the continuum, denoted c, and its successor cardinal, c+, play important roles. We show that if κ>c+, then no ψ(κ,M) has any ordinal as a Stone-?ech remainder. If κ?c then for every ordinal δ<κ+ there exists Mδ⊂ω[κ], a MADF, such that βψ(κ,Mδ)?ψ(κ,Mδ) is homeomorphic to δ+1. For κ=c+, βψ(κ,Mδ)?ψ(κ,Mδ) is homeomorphic to δ+1 if and only if c+?δ<c+⋅ω. 相似文献
8.
We prove Lp-spectral independence for generators of C0-semigroups estimated by the positive C0-semigroup . In the preliminary process of the proof, we obtain the asymptotic expansion formula for the integral kernel of the C0-semigroup . 相似文献
9.
Donald I. Cartwright 《Monatshefte für Mathematik》2001,247(1):93-109
To any locally finite thick building of type there is naturally associated a commutative algebra of operators. When is constructed from a local field F with local ring , and , then is isomorphic to the convolution algebra of compactly supported bi-K-invariant functions on PGL(n+1,F). We give a proof, valid for any , that the multiplicative functionals on may all be expressed in terms of Hall–Littlewood polynomials. Regarding as a subalgebra of the C *-algebra of bounded operators on the space of square summable functions on the vertex set of , we find the spectrum of the C *-algebra , the closure of . This generalizes results obtained in [3] when n = 1 and in [5] when n = 2. 相似文献
10.
本文首先给出(α,β)-γ开集定义,获得了(α,β)-γ开集性质;然后引入了(α,β)-γ-Ti空间和(α,β)-γ-Ti*空间概念(i=0,1/2,1,2,5/2),并得到它们更广泛的拓扑性质. 相似文献
11.
12.
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
13.
X. J. Long 《Journal of Optimization Theory and Applications》2011,148(1):197-208
The purpose of this paper is to consider a class of nondifferentiable multiobjective fractional programming problems in which
every component of the objective function contains a term involving the support function of a compact convex set. Based on
the (C,α,ρ,d)-convexity, sufficient optimality conditions and duality results for weakly efficient solutions of the nondifferentiable
multiobjective fractional programming problem are established. The results extend and improve the corresponding results in
the literature. 相似文献
14.
Jeff Edmonds 《Discrete and Computational Geometry》2008,39(4):747-765
We give a new algorithm for enumerating all possible embeddings of a metric space (i.e., the distances between every pair
within a set of n points) into ℝ2 Cartesian space preserving their l
∞ (or l
1) metric distances. Its expected time is
(i.e., within a poly-log of the size of the input) beating the previous
algorithm. In contrast, we prove that detecting l
∞3 embeddings is NP-complete. The problem is also NP-complete within l
12 or l
∞2 with the added constraint that the locations of two of the points are given or alternatively that the two dimensions are
curved into a three-dimensional sphere. We also refute a compaction theorem by giving a metric space that cannot be embedded
in l
∞3; however, it can be embedded if any single point is removed.
This research is partially supported by NSERC grants. I would like to thank Steven Watson for his extensive help on this paper. 相似文献
15.
16.
17.
In the present paper, for a boundary value problem with noncoordinated degeneration of the data and a singularity in the solution,
we show that the R
ν
-generalized solution belongs to the weighted space W
2,ν+gb
2+κ+1/κ+2 (Ω, δ)(κ > 0).
Original Russian Text ? V.A. Rukavishnikov, E.V. Kuznetsova, 2009, published in Differentsial’nye Uravneniya, 2009, Vol. 45,
No. 6, pp. 894–898. 相似文献
18.
Let X and Y be Banach spaces and ψ a continuous convex function on the unit interval [0,1] satisfying certain conditions. Let X⊕ψY be the direct sum of X and Y equipped with the associated norm with ψ. We show that X⊕ψY is uniformly convex if and only if X,Y are uniformly convex and ψ is strictly convex. As a corollary we obtain that the ?p,q-direct sum (not p=q=1 nor ∞), is uniformly convex if and only if X,Y are, where ?p,q is the Lorentz sequence space. These results extend the well-known fact for the ?p-sum . Some other examples are also presented. 相似文献
19.
解题中我们常用到asinx +bcosx =a2 +b2 sin(x +ψ) ,但若只知其中tanψ =ba,就会出现问题 ,下面通过实例进行探讨 .例 1 已知x∈ [0 ,π2 ] ,求函数y =3sinx -cosx的值域 .分析 函数 y =3sinx -cosx可变为y =2sin(x +ψ) ,其中tanψ =-13 .若取 ψ =-π6,则 y =2sin(x -π6) ,x -π6∈ [-π6,π3 ] , ∴ y∈ [-1,3 ] .若取 ψ =-5π6,则 y =2sin(x -5π6) ,x -5π6∈ [5π6,4π3 ] , ∴ y∈ [-3 ,1] .得出了不同结果 ,哪一个对呢 ?难以确定 .这表明仅由tanψ =ba确定 ψ不行 !图 1那么如何确定 ψ呢 ?考虑asinx +bcosx =a2 +b2 sin(x… 相似文献
20.
Yong Zhou 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,11(3):191-204
Considering the Navier–Stokes equations in
W ì \mathbbRn\Omega \subset {\mathbb{R}}^n, we prove the asymptotic stability for weak solutions in the marginal class u ∈ C
B
(0, ∞; L
n
) with arbitrary initial and external perturbations. 相似文献