共查询到20条相似文献,搜索用时 31 毫秒
1.
Jong Taek Cho 《Rendiconti del Circolo Matematico di Palermo》1994,43(1):141-160
We define four new classes of contact metric manifoulds using Tanaka connection and Jacobi operators. We prove that a contact metric manifold with the structure vector field ξ belonging to thek-nullity distribution is contact metric locally ?-symmetric (in the sense of D. B. Blair) if and only if the manifold is a and space. Also, we prove that a 3-dimensional contact metric and is locally ?-symmetric (in the sense of D. E. Blair) and give counter-examples of the converse. 相似文献
2.
For linear combinations of Gamma operators, if 0<a<2r, 1/2-1/2r≤λ≤l, or 0≤λ<1/2-1/2r(r≥2),0<a<r+10<a<(r+1)/1-λ, we obtain an equivalent theorem with ωuλρ(f ,t) instead of ωrλφ(f,t), where ωuφ(f,t) is theDitzian-Totik moduli of smoothness. 相似文献
3.
A. I. Rubinshtein 《Analysis Mathematica》1996,22(3):199-212
ОсНОВНОИ РЕжУльтАт Ё тОИ стАтьИ жАклУЧАЕт сь В слЕДУУЩЕМ. ЕслИ с ФИксИРОВАННыМr=2, 3,..., тО Дль тОгО, ЧтОБы ИМЕлО М ЕстО (*) гДЕ ДОстАтОЧНО ВыпОлНЕН ИЕ слЕДУУЩИх УслОВИИ: 1) ЕслИ $$1< \frac{{n_\nu + 1}}{{n_\nu }} = g_\nu \in N, \nu = 0,1,$$ тО Дль кАжДОгОΝ=0,1,... ИМЕ Ет МЕстО (**) 2) ЕслИ тО (***) $$n_{\nu + 1} \geqslant (2r - 1)n_\nu , \nu = 0,1,...$$ . ЕслИ И тО УслОВИь (**), (***) ьВльУтсь тАкжЕ НЕОБхОДИМыМИ Д ль (*). 相似文献
4.
Janusz Kaptur 《Rendiconti del Circolo Matematico di Palermo》1981,30(3):471-476
LetX be a real linear space; if is a linear topology onX, let denote the class of all bounded with respect to subsets ofX. In this paper it is shown that the spaceX is algebraically finite dimensional if and only if the class of all convex, absorbing and radially bounded subsets ofX is included in the intersection of all , where runs the set of all linear topologies onX. 相似文献
5.
N. D. Macheras 《Rendiconti del Circolo Matematico di Palermo》1995,44(3):441-456
We introduce a category of (topological) measure spaces in which inductive limitis exist and where the Banach spaces and (1≤p≤+∞) are isometric for arbitrary inductive systems of (topological) measure spaces. 相似文献
6.
Shao Qiman 《分析论及其应用》1991,7(1):35-38
In [1], Butzer and Kirschfink discussed the convergence rates for C[0,1]-valued dependent random functions on Donsker's weak invariance principle and introduced the concept of dependency from below to deal with the martingale difference sequence. They asserted in their Lemma 8 that Lemma A. A martingale difference sequence (Xn,Fn,n≥1) with is dependent from below, i.e., for each 1≤i≤n and each n≥1 . The purpose of this note is to prove that Lemma A is not always true and to improve the conditions of Butzer and Kirschfink. We shall apply the notations in [1]. 相似文献
7.
For γ ∈ ?letQ 〈γ〉 = ?[i]+?[i]j. where j. is a hypercomplex number withj2 = γ, and define addition and multiplication formally with respect to $zj = j\overline z $ for all z ∈ ?[i], so thatQ〈γ〉 becomes a quaternion algebra over the rationals. Further fix γ s.t.Q 〈γ 〉 is a division algebra and define for real X ≥ 1 where |Re(α)|, |Im(α)|, |Re(β)|, |Im(ö)|≤ X and Generalizing former results concerning Hamilton’s quaternions (i.e. the case γ =- 1) we show that, as X → ∞, when γ < 0, when γ > 0, when γ < 0, wheny γ 0. Thereby δ(t) is any upper bound of the error term in Dirichlet’s divisor problem, e.g. δ(t) =t0.315, Cγ, Dγ > 0 are numerical constants, and c, d are given by c := π(1 + log 2 - 2η) and d := π2(1 + 4 log 4 - 4π)/8, where π = 0.577 … is Euler’s constant. 相似文献
8.
It is shown that if is any variety of algebras all of whose congruence lattices are modular, then the congruence lattice of every algebra in satisfies the Arguesian law. 相似文献
9.
Let be a De Possel differentiation basis in a complete measure space , with μ≥0, μ(X)<+∞; letB be a Banach space and . When the F′ exists μ-a.e. onX, we prove that for eachp>0, the μ-integral of‖F′‖ p is the lower-bound of a class ofp-variations. 相似文献
10.
We give new sufficient conditions in order that a projective tensor product of Banach spaces contains complemented copies of ?1, which provides us new examples of this situation. 相似文献
11.
N. V. Kuznetsov 《Journal of Mathematical Sciences》1985,29(2):1131-1159
The convolution is defined as the sum where for n≠0 and W0,W1 are arbitrary smooth functions. Question: how to express these sums in the form of the combinations of the N-th Fourier coefficients of the eigenfunctions of the automorphic Laplacian? The answer is given in terms of the bilinear form of the Hecke series associated with the eigenfunctions of the automorphic Laplacian and with regular cusp forms. The final identity may lead to a new possibility for the solution of the moment problem of the Riemann zeta-function. 相似文献
12.
We shall prove the following partition theorems:
- For every setS and for each cardinal ? ≥ ω, |S| ≥ ? there exists a partitionT: [S]? → 2? such that for every pairwise disjoint familie and everyα < 2? there exists a set
- Suppose ? ≥ ω, 2 andS an arbitrary set, 2|S| ≤ (2?)+ω Then there exists a partitionT: P(S) → 2? such that for every pairwise disjoint family and everyα < 2? there exists a set Both theorems will give partial answers to an Erd?s problem.
13.
Giuseppe Tomassini 《Rendiconti del Circolo Matematico di Palermo》1991,40(2):281-297
Si considera l’equazione di Levi su un aperto di e si studiano alcune proprietà delle sue soluzioni regolari. 相似文献
14.
15.
G. R. Baird 《Semigroup Forum》1972,5(1):228-235
Let S be a regular semigroup. The lattice of all idempotent-separating congruences on S and the lattice of all group congruences on S are both modular sublattices of the full lattice of congruences on S. It is evident that the set theoretical union of these two sublattices, (S), is also a sublattice of the full lattice of congruences on S. It is natural to ask: Under what conditions is the sublattice (S) modular? In this paper we obtain a necessary and sufficient condition for the sublattice (S) to be modular when S is what we call a θ-regular semigroup. Bisimple ω-semigroups and simple regular ω-semigroups are θ-regular semigroups and so this paper extends the work of Munn [5] and Baird [1]. 相似文献
16.
Il contenuto di questo lavoro consiste nel mostrare che le fibrazioni dei near-field regolari di dimensionet+1 sul nucleo , quando , si ottengono da fibrazioni regolari con una operazione di scambio fra alcuni sistemi di matrici, che generalizza il procedimento di sostituzione di regoli con regoli opposti di quadriche rigate nel caso di dimensione due sul nucleo. 相似文献
17.
A. -R. K. Ramazanov 《Analysis Mathematica》1994,20(4):263-281
Получен аналог теоре мы Джексона о приближ ении полиномами в метрике Ф-вариации; для некото рых классов функций (в ыпуклых, конечной вариации, с заданным модулем неп рерывности) установл ено соотношение типа сла бой эквивалентности, которое связывает ме жду собой рациональн ые аппроксимации, в этой и равномерной метриках Даны оценкиε-энтропи и в метрике Ф-вариации классов функций с заданным мо дулем Ф-абсолютной непреры вности и с заданным мо дулем непрерывности. 相似文献
18.
We consider mean-square optimal linear estimation of the transform $$A\xi = \sum\limits_{k,j = 0}^\infty {a(k,j)} \xi ( - k, - j)$$ of the homogeneous random field ξ(k, j) with density f(λ, Μ) from the observations ξ(k, j) + η(k, j) with k ≤ 0, j ≤ 0, where η(k, j) is a random field with orthogonal values uncorrelated with ξ(k, j) (white noise). We determine the worst spectral densitiesf 0(λ, Μ) ∈ and the minimax (robust) spectral characteristics of the optimal estimator of the transform Aξ for various density classes . 相似文献
19.
Michael Mörs 《Graphs and Combinatorics》1985,1(1):167-183
LetA be a set ofk-subsets of {1,...,n} with . We determine the minimal cardinality of thel-shadow ofA. This theorem generalizes a theorem of Kruskal [10], Katona [8], Lindström [11] and other which gives a solution for the problem without the condition . Furthermore we give a necessary and sufficient condition for the uniqueness of the solution in the KKL theorem. 相似文献
20.
Edmondo Bedocchi 《Rendiconti del Circolo Matematico di Palermo》1981,30(3):397-415
LetF q (q=pr) be a field of characteristicp>3 andA the set of all elliptic cubic curves overF q having a given absolute invariantj. Furthermore let ≈be the following equivalence relation: « if and only if and Fq are isomorphic overF q as abelian varieties». The aim of this paper is to study the equivalence classes inA, induced by ≈, and the Frobenius' traces of the cubic curves belonging to different subclasses ofA. 相似文献