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1.
Let X be a Banach space. We give characterizations of when is a u-ideal in for every Banach space Y in terms of nets of finite rank operators approximating weakly compact operators. Similar characterizations are given for
the cases when is a u-ideal in for every Banach space Y, when is a u-ideal in for every Banach space Y, and when is a u-ideal in for every Banach space Y. 相似文献
2.
Dong Zhe 《Czechoslovak Mathematical Journal》2006,56(2):287-298
In this paper we investigate finite rank operators in the Jacobson radical
of Alg(
), where
are nests. Based on the concrete characterizations of rank one operators in Alg(
) and
, we obtain that each finite rank operator in
can be written as a finite sum of rank one operators in
and the weak closure of
equals Alg(
) if and only if at least one of
is continuous. 相似文献
3.
Ján Jakubík 《Czechoslovak Mathematical Journal》2008,58(3):833-848
Let be an infinite cardinal. We denote by the collection of all -representable Boolean algebras. Further, let be the collection of all generalized Boolean algebras B such that for each b ∈ B, the interval [0, b] of B belongs to . In this paper we prove that is a radical class of generalized Boolean algebras. Further, we investigate some related questions concerning lattice ordered
groups and generalized MV-algebras.
This work was supported by Science and Technology Assistance Agency under the contract No. APVT-51-032002.
This work has been partially supported by the Slovak Academy of Sciences via the project Center of Excellence-Physics of Information. 相似文献
4.
Projectively condensed semigroups,generalized completely regular semigroups and projective orthomonoids 总被引:1,自引:0,他引:1
The class of projectively condensed semigroups is a quasivariety of unary semigroups, the class of projective orthomonoids is a subquasivariety
of . Some well-known classes of generalized completely regular semigroups will be regarded as subquasivarieties of . We give the structure semilattice composition and the standard representation of projective orthomonoids, and then obtain
the structure theorems of various generalized orthogroups.
Partially supported by a UGC (HK) grant #2060123 (04-05). 相似文献
5.
Yonutz V. Stanchescu 《Combinatorica》2008,28(3):343-355
We describe the structure of three dimensional sets of lattice points, having a small doubling property. Let be a finite subset of ℤ3 such that dim = 3. If and , then lies on three parallel lines. Moreover, for every three dimensional finite set that lies on three parallel lines, if , then is contained in three arithmetic progressions with the same common difference, having together no more than terms. These best possible results confirm a recent conjecture of Freiman and cannot be sharpened by reducing the quantity
υ or by increasing the upper bounds for . 相似文献
6.
Debashish Goswami 《Proceedings Mathematical Sciences》2009,119(1):63-70
We prove that an arbitrary (not necessarily countably generated) Hilbert G - module on a G - C
* algebra admits an equivariant embedding into a trivial G - module, provided G is a compact Lie group and its action on is ergodic. 相似文献
7.
A. M. Matveeva 《Russian Mathematics (Iz VUZ)》2008,52(7):66-70
We study the geometry of affine and normal connections induced by a complete normalization of mutually orthogonal distributions $ \mathcal{M} We study the geometry of affine and normal connections induced by a complete normalization of mutually orthogonal distributions
and in conformal space C
n
, where is a distribution of hyperplane elements, and is a distribution of line elements. We consider invariant fields of pencils that are parallel with respect to the normal
connection along any curve belonging to the distribution .
Original Russian Text ? A.M. Matveeva, 2008, published in Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika, 2008, No. 7,
pp. 79–84. 相似文献
8.
We classify the quadratic extensions and the finite groups G for which the group ring [G] of G over the ring of integers of K has the property that the group of units of augmentation 1 is hyperbolic. We also construct units in the ℤ-order of the quaternion algebra , when it is a division algebra. 相似文献
9.
Concettina Galati 《Rendiconti del Circolo Matematico di Palermo》2009,58(2):211-243
Let be a smooth family of surfaces whose general fibre is a smooth surface of ℙ3 and whose special fibre has two smooth components, intersecting transversally along a smooth curve R. We consider the Universal Severi-Enriques variety on . The general fibre of is the variety of curves on in the linear system with k cusps and δ nodes as singularities. Our problem is to find all irreducible components of the special fibre of . In this paper, we consider only the cases (k, δ) = (0, 1) and (k, δ) = (1, 0). In particular, we determine all singular curves on the special fibre of which, counted with the right multiplicity, are a limit of 1-cuspidal curves on the general fibre of .
相似文献
10.
Miroslav Pavlović 《Czechoslovak Mathematical Journal》2008,58(4):1039-1043
For a C
1-function f on the unit ball ⊂ ℂ
n
we define the Bloch norm by , where is the invariant derivative of f, and then show that
.
Supported by MNZŽS Serbia, Project No. 144010. 相似文献
11.
Changguo Wei 《Proceedings Mathematical Sciences》2008,118(4):517-524
Some results on A
-algebras are given. We study the problem when ideals, quotients and hereditary subalgebras of A
-algebras are A
-algebras or A
-algebras, and give a necessary and sufficient condition of a hereditary subalgebra of an A
-algebra being an A
-algebra. 相似文献
12.
We prove that an n-gon is pedal strong Fagnano trajectory in some convex polygonal billiard table if and only if it is a convex Poncelet n-gon.
相似文献
13.
V. D. Lyakhovsky 《Journal of Mathematical Sciences》2008,151(2):2907-2923
New solutions of twist equations for the universal enveloping algebras U (An−1) are found. These solutions can be represented as products of full chains of extended Jordanian twists Abelian factors (“rotations”) , and sets of quasi-Jordanian twists . The latter are generalizations of Jordanian twists (with carrier b2) for special deformed extensions of the Hopf algebra U (b2). The carrier subalgebra for the composition is a nonminimal parabolic subalgebra in A
n−1 such that . The parabolic twisting elements are obtained in an explicit form. Details of the construction are illustrated by considering the examples n = 4 and n = 11.
Bibliography: 21 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 347, 2007, pp. 187–213. 相似文献
14.
Let H olenote a complex separable Hilbert space and L(H) denote the collection of bounded linear operators on H. An operator T ∈ L(H) is said to be strongly irreducible if T does not commute with any nontrivial idempotent. Herrero and Jiang showed that the norm-closure of the class of all strongly irreducible operators is the class of all operators with connected spectrum. This result can be considered as an approximate inverse of the Riesz decomposition theorem. In the paper, we give a more precise charact... 相似文献
15.
G. Androulakis P. Dodos G. Sirotkin V. G. Troitsky 《Israel Journal of Mathematics》2009,169(1):221-250
V. D. Milman proved in [20] that the product of two strictly singular operators on L
p
[0, 1] (1 ⩽ p < 1) or on C[0, 1] is compact. In this note we utilize Schreier families in order to define the class of -strictly singular operators, and then we refine the technique of Milman to show that certain products of operators from this
class are compact, under the assumption that the underlying Banach space has finitely many equivalence classes of Schreier-spreading
sequences. Finally we define the class of -hereditarily indecomposable Banach spaces and we examine the operators on them.
This project originated at SUMIRFAS conference in 2005 in Texas A&M University. The authors wish to thank the organizers of
the SUMIRFAS conference for their hospitality. 相似文献
16.
David Pauksztello 《Central European Journal of Mathematics》2008,6(1):25-42
In the work of Hoshino, Kato and Miyachi, [11], the authors look at t-structures induced by a compact object, , of a triangulated category, , which is rigid in the sense of Iyama and Yoshino, [12]. Hoshino, Kato and Miyachi show that such an object yields a non-degenerate
t-structure on whose heart is equivalent to Mod(End()op). Rigid objects in a triangulated category can the thought of as behaving like chain differential graded algebras (DGAs).
Analogously, looking at objects which behave like cochain DGAs naturally gives the dual notion of a corigid object. Here,
we see that a compact corigid object, , of a triangulated category, , induces a structure similar to a t-structure which we shall call a co-t-structure. We also show that the coheart of this non-degenerate co-t-structure is equivalent to Mod(End()op), and hence an abelian subcategory of .
相似文献
17.
E. Ekici 《Acta Mathematica Hungarica》2007,117(4):325-333
The main purpose of this paper is to introduce the concepts of *-sets, *-continuous functions and to obtain new decompositions of continuous and ηζ-continuous functions. Moreover, properties of *-sets and some properties of -sets are discussed.
相似文献
18.
Małgorzata Filipczak Małgorzata Terepeta 《Rendiconti del Circolo Matematico di Palermo》2009,58(2):245-255
Let be a ψ-density topology for a fixed function ψ. This paper is concerned with the family of ψ-continuous functions, that means continuous functions from (ℝ, ) into (ℝ, ). The family of such functions forms a lattice and is not closed under addition and uniform convergence. There exist functions
ψ for which even linear functions are not ψ-continuous.
相似文献
19.
Let G be the complex general linear group and its Lie algebra equipped with a factorizable Lie bialgebra structure; let Uħ() be the corresponding quantum group. We construct explicit Uħ()-equivariant quantization of Poisson orbit bundles O
λ → O
μ in *. 相似文献
20.
Michael I. Hartley 《Combinatorica》2008,28(3):299-314
This article completes the classification of finite universal locally projective regular abstract polytopes, by summarising
(with careful references) previously published results on the topic, and resolving the few cases that do not appear in the
literature. In rank 4, all quotients of the locally projective polytopes are also noted. In addition, the article almost completes
the classification of the infinite universal locally projective polytopes, except for the {{5,3,3,},{3,3,5}15} and its dual. It is shown that this polytope cannot be finite, but its existence is not established. The most remarkable
feature of the classification is that a nondegenerate universal locally projective polytope is infinite if and only if the rank of is 5 and the facets of or its dual are the hemi-120-cell {5,3,3}15. 相似文献