共查询到20条相似文献,搜索用时 46 毫秒
1.
Tunay Bilgin 《Czechoslovak Mathematical Journal》2005,55(3):691-697
The definition of lacunary strongly convergence is extended to the definition of lacunary strong (A
σ
, p)-convergence with respect to invariant mean when A is an infinite matrix and p = (p
i
) is a strictly positive sequence. We study some properties and inclusion relations. 相似文献
2.
Claudia A. Sanza 《Central European Journal of Mathematics》2008,6(3):372-383
n×m-valued Łukasiewicz algebras with negation were introduced and investigated in [20, 22, 23]. These algebras constitute a
non trivial generalization of n-valued Łukasiewicz-Moisil algebras and in what follows, we shall call them n×m-valued Łukasiewicz-Moisil algebras (or LM
n×m
-algebras). In this paper, the study of this new class of algebras is continued. More precisely, a topological duality for
these algebras is described and a characterization of LM
n×m
-congruences in terms of special subsets of the associated space is shown. Besides, it is determined which of these subsets
correspond to principal congruences. In addition, it is proved that the variety of LM
n×m
-algebras is a discriminator variety and as a consequence, certain properties of the congruences are obtained. Finally, the
number of congruences of a finite LM
n×m
-algebra is computed.
相似文献
3.
J.C. FERRANDO S. MOLL 《数学学报(英文版)》2007,23(9):1593-1600
In this paper, we show, among other results, that if X is a [separable] locally compact space X [satisfying the first countability axiom] then the space Cc (X) has countable tightness [if and only if it has bounding tightness] if and only if it is Frechet-Urysohn, if and only if Cc (X) contains a dense (LM) subspace and if and only if X is a-compact. 相似文献
4.
We prove that a locally compact ANR-space X is a Q-manifold if and only if it has the Disjoint Disk Property (DDP), all points of X are homological Z
∞-points and X has the countable-dimensional approximation property (cd-AP), which means that each map f: K → X of a compact polyhedron can be approximated by a map with the countable-dimensional image. As an application we prove that
a space X with DDP and cd-AP is a Q-manifold if some finite power of X is a Q-manifold. If some finite power of a space X with cd-AP is a Q-manifold, then X
2 and X × [0, 1] are Q-manifolds as well. We construct a countable family χ of spaces with DDP and cd-AP such that no space X ∈ χ is homeomorphic to the Hilbert cube Q whereas the product X × Y of any different spaces X, Y ∈ χ is homeomorphic to Q. We also show that no uncountable family χ with such properties exists.
This work was supported by the Slovenian-Ukrainian (Grant No. SLO-UKR 04-06/07) 相似文献
5.
Eungil Ko 《Integral Equations and Operator Theory》2007,59(2):173-187
In this paper, we consider the special case of the question raised by Halmos (see below). In particular, we show that if Tk is p-hyponormal, then T is a subscalar operator of order 4k. As a corollary, we obtain that if Tk is p-hyponormal and σ(T) has nonempty interior in the plane, then T has a nontrivial invariant subspace. 相似文献
6.
Let p be a prime number, p > 2. A closed Riemann surface which can be realized as a p-sheeted covering of the Riemann sphere is called p-gonal, and such a covering is called a p-gonal morphism. If the p-gonal morphism is a cyclic regular covering, the Riemann surface is called a cyclic p-gonal Riemann surface. Accola showed that if the genus is greater than (p − 1)2 the p-gonal morphism is unique. Using the characterization of p-gonality by means of Fuchsian groups we show that there exists a uniparametric family of cyclic p-gonal Riemann surfaces of genus (p − 1)2 which admit two p-gonal morphisms. In this work we show that these uniparametric families are connected spaces and that each of them is the
Riemann sphere without three points. We study the Hurwitz space of pairs (X, f), where X is a Riemann surface in one of the above families and f is a p-gonal morphism, and we obtain that each of these Hurwitz spaces is a Riemann sphere without four points. 相似文献
7.
In [1], we defined c(G), q(G) and p(G). In this paper we will show that if G is a p-group, where p is an odd prime and |G| ≤ p
4, then c(G) = q(G) = p(G). However, the question of whether or not there is a p-group G with strict inequality c(G) = q(G) < p(G) is still open. 相似文献
8.
Jinjin Li 《Czechoslovak Mathematical Journal》2005,55(4):941-945
In this note we study the relation between k
R
-spaces and k-spaces and prove that a k
R
-space with a σ-hereditarily closure-preserving k-network consisting of compact subsets is a k-space, and that a k
R
-space with a point-countable k-network consisting of compact subsets need not be a k-space.
This work was supported by the NSF of China (10271056). 相似文献
9.
We show that an infinite cyclic covering space M′ of a PD
n
-complex M is a PD
n-1-complex if and only if χ(M) = 0, M′ is homotopy equivalent to a complex with finite [(n−1)/2]-skeleton and π1(M′) is finitely presentable. This is best possible in terms of minimal finiteness assumptions on the covering space. We give
also a corresponding result for covering spaces M
ν with covering group a PD
r
-group under a slightly stricter finiteness condition.
相似文献
10.
Abdellah El Kinani 《Rendiconti del Circolo Matematico di Palermo》2008,57(2):229-238
We endow any proper A-convex H*-algebra (E, τ) with a locally pre-C*-topology. The latter is equivalent to that introduced by the pre C*-norm given by Ptàk function when (E, τ) is a Q-algebra. We also prove that the algebra of complex numbers is the unique proper locally A-convex H*-algebra which is barrelled and Q-algebra.
相似文献
11.
Lascar described E
KP
as a composition of E
L
and the topological closure of E
L
(Casanovas et al. in J Math Log 1(2):305–319). We generalize this result to some other pairs of equivalence relations. Motivated
by an attempt to construct a new example of a non-G-compact theory, we consider the following example. Assume G is a group definable in a structure M. We define a structure M′ consisting of M and X as two sorts, where X is an affine copy of G and in M′ we have the structure of M and the action of G on X. We prove that the Lascar group of M′ is a semi-direct product of the Lascar group of M and G/G
L
. We discuss the relationship between G-compactness of M and M′. This example may yield new examples of non-G-compact theories.
The first author is supported by the Polish Goverment grant N N201 384134. The second author is supported by the Polish Goverment
grant N201 032 32/2231. 相似文献
12.
V. K. Maslyuchenko V. V. Mykhailyuk O. I. Filipchuk 《Ukrainian Mathematical Journal》2008,60(11):1803-1812
We introduce the notion of categorical cliquish mapping and show that, for each K
h
C-mapping f: X × Y → Z, where X is a topological space, Y is a space with the first axiom of countability, and Z is a Moore space, with categorical-cliquish horizontal y-sections f
y
, the sets C
y
(f) are residual G
δ-type sets in X for every y ∈ Y.
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 11, pp. 1539–1547, November, 2008. 相似文献
13.
Serge Skryabin 《Algebras and Representation Theory》2011,14(5):803-822
Let H be a Hopf algebra over a field. It is proved that every H-semiprime right artinian left H-module algebra A is quasi-Frobenius and H-semisimple. If H grows slower than exponentially, then all H-equivariant A-modules are shown to be A-projective. With the additional assumption that H is cosemisimple it is proved that the Jacobson radical of any right artinian left H-module algebra is stable under the action of H. 相似文献
14.
For a field F,let Gn(F) = {{a,Φn(a)} ∈ K2(F) | a,Φn(a) ∈ F*},where Φn(x) is the n-th cyclotomic polynomial.At first,by using Faltings' theorem on Mordell conjecture it is proved that if F is a number field and if n = 4,8,12 is a positive integer having a square factor then Gn(F) is not a subgroup of K2(F),and then by using the results of Manin,Grauert,Samuel and Li on Mordell conjecture theorem for function fields,a similar result is established for function fields over an algebraically closed field. 相似文献
15.
In this paper we study C0-semigroups on X × Lp( − h, 0; X) associated with linear differential equations with delay, where X is a Banach space. In the case that X is a Banach lattice with order continuous norm, we describe the associated modulus semigroup, under minimal assumptions on
the delay operator. Moreover, we present a new class of delay operators for which the delay equation is well-posed for p in a subinterval of [1,∞).
Dedicated to the memory of H. H. Schaefer 相似文献
16.
An f-coloring of a graph G is an edge-coloring of G such that each color appears at each vertex v V(G) at most f(v) times. The minimum number of colors needed to f-color G is called the f-chromatic index of G and is denoted by X′f(G). Any simple graph G has the f-chromatic index equal to △f(G) or △f(G) + 1, where △f(G) =max v V(G){[d(v)/f(v)]}. If X′f(G) = △f(G), then G is of f-class 1; otherwise G is of f-class 2. In this paper, a class of graphs of f-class 1 are obtained by a constructive proof. As a result, f-colorings of these graphs with △f(G) colors are given. 相似文献
17.
A set-valued mapping F from a topological space X to a topological space Y is called a cusco map if F is upper semicontinuous and F(x) is a nonempty, compact and connected subset of Y for each x ∈ X. We denote by L(X), the space of all subsets F of X × ℝ such that F is the graph of a cusco map from the space X to the real line ℝ. In this paper, we study topological properties of L(X) endowed with the Vietoris topology.
The second author is supported by the SPM fellowship awarded by the Council of Scientific and Industrial Research, India. 相似文献
18.
Mikhail Ershov 《Israel Journal of Mathematics》2007,158(1):297-347
Let D be a finite dimensional division algebra over a local field of characteristic p and let SL
1(D) denote the group of elements of reduced norm 1 in D. In this paper we prove that SL
1(D) is finitely presented as a profinite group.
This work is part of the author’s Ph.D. Thesis at Yale University. 相似文献
19.
Lawrence E. Wilson 《Israel Journal of Mathematics》2003,138(1):1-17
We prove that if the nilpotence class of ap-group is strictly less thanp
kthen every product ofp
k-thpowers can be written as thep-th power of an element. Scoppola and Shalev have proven the same thing for groups of class strictly less thanp
k−p
k−1. They also provide an example which proves that ours is the best possible result. This is a generalization of the well
known fact that in groups of class strictly less thanp every product ofp-powers is again ap-th power. Along the way we prove results of independent interest on dimension subgroups ofp-groups. 相似文献
20.
Bao Qin Li 《Israel Journal of Mathematics》2004,143(1):131-140
We describe entire solutions inC
n
of non-linear partial differential equations of the form (∂w/∂z
j
)
k
=f(w), wheref is a meromorphic function in the complex plane andk is a positive integer.
Supported in part by the National Science Foundation (USA) Grant DMS-0100486. 相似文献