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1.
In the present paper we consider a von Neumann algebra M with a faithful normal semi-finite trace τ, and {α
t
}, a strongly continuous extension to L
p
(M, τ) of a semigroup of absolute contractions on L
1(M, τ). By means of a non-commutative Banach Principle we prove for a Besicovitch function b and x ∊ L
p
(M, τ), that the averages 1/T ∫0
T
b(t)α
t
(x)dt converge bilateral almost uniformly in L
p
(M, τ) as T → 0.
Communicated by Dénes Petz 相似文献
2.
Bao Qin Li 《Mathematische Zeitschrift》2008,258(4):763-771
We show that meromorphic solutions f, g of f
2 + g
2 = 1 in C2 must be constant, if f
z2 and g
z1 have the same zeros (counting multiplicities). We also apply the result to characterize meromorphic solutions of certain
nonlinear partial differential equations. 相似文献
3.
J. Wei recently proposed a concept of *
s
-modules which is another generalization of *-modules besides *
n
-modules [J. Algebra, 2005, 291: 312–324]. In this paper, we consider the co-*
s
-modules and give some characterizations and properties. It is found that the class of co-*
s
-modules contains co-selfsmall injective cogenerators. The relations between co-*
s
-modules and co-*
n
-modules are also considered. 相似文献
4.
ZhangJianfeng 《高校应用数学学报(英文版)》2005,20(2):183-196
Let M^n be a closed spacelike submanifold isometrically immersed in de Sitter space Sp^(n p)(c), Denote by R,H and S the normalized scalar curvature,the mean curvature and the square of the length of the second fundamental form of M^n ,respectively. Suppose R is constant and R≤c. The pinching problem on S is studied and a rigidity theorem for M^n immersed in Sp^(n p)(c) with parallel normalized mean curvature vector field is proved. When n≥3, the pinching constant is the best. Thus, the mistake of the paper “Space-like hypersurfaces in de Sitter space with constant scalar curvature”(see Manus Math, 1998,95 :499-505) is corrected. Moreover,the reduction of the codimension when M^n is a complete submanifold in Sp^(n p)(c) with parallel normalized mean curvature vector field is investigated. 相似文献
5.
L
p
approximation capability of radial basis function (RBF) neural networks is investigated. If g: R
+1 → R
1 and ∈ L
loc
p
(R
n
) with 1 ≤ p < ∞, then the RBF neural networks with g as the activation function can approximate any given function in L
p
(K) with any accuracy for any compact set K in R
n
, if and only if g(x) is not an even polynomial.
Partly supported by the National Natural Science Foundation of China (10471017) 相似文献
6.
J. C. Gómez-Larrañaga F. González-Acuña Wolfgang Heil 《Mathematische Zeitschrift》2008,259(2):419-432
A closed topological n-manifold M
n
is of S
1-category 2 if it can be covered by two open subsets W
1,W
2 such that the inclusions W
i
→ M
n
factor homotopically through maps W
i
→ S
1 → M
n
. We show that the fundamental group of such an n-manifold is a cyclic group or a free product of two cyclic groups with nontrivial amalgamation. In particular, if n = 3, the fundamental group is cyclic.
相似文献
7.
Aldo Portela 《Bulletin of the Brazilian Mathematical Society》2007,38(4):623-633
Although every Cantor subset of the circle (S1) is the minimal set of some homeomorphism of S1, not every such set is minimal for a C1 diffeomorphism of S1. In this work, we construct new examples of Cantor sets in S1 that are not minimal for any C1-diffeomorphim of S1. 相似文献
8.
Jia Gao 《高校应用数学学报(英文版)》2007,22(2):174-180
Let L^p(Ω, H^n) indicate the L^P-space of the maps for Heisenberg group target. In this paper some new properties are obtained for the space L^p(Ω, H^n) 相似文献
9.
For any complex valued L
p
-function b(x), 2 ≤ p < ∞, or L
∞-function with the norm ‖b↾L
∞‖ < 1, the spectrum of a perturbed harmonic oscillator operator L = −d
2/dx
2 + x
2 + b(x) in L
2(ℝ1) is discrete and eventually simple. Its SEAF (system of eigen- and associated functions) is an unconditional basis in L
2(ℝ). 相似文献
10.
As the main result, we show that if G is a finite group such that Γ(G) = Γ(2
F
4(q)), where q = 22m+1 for some m ≧ 1, then G has a unique nonabelian composition factor isomorphic to 2
F
4(q). We also show that if G is a finite group satisfying |G| =|2
F
4(q)| and Γ(G) = Γ(2
F
4(q)), then G ≅ 2
F
4(q). As a consequence of our result we give a new proof for a conjecture of W. Shi and J. Bi for 2
F
4(q).
The third author was supported in part by a grant from IPM (No. 87200022). 相似文献