共查询到10条相似文献,搜索用时 203 毫秒
1.
J. Hagler 《Proceedings of the American Mathematical Society》2002,130(11):3313-3324
Let be a real or complex Banach space and . Then contains a -complemented, isometric copy of if and only if contains a -complemented, isometric copy of if and only if contains a subspace -asymptotic to .
2.
Danny Calegari Nathan M. Dunfield 《Proceedings of the American Mathematical Society》2006,134(11):3131-3136
We give an example of a subgroup of which is a strictly ascending HNN extension of a non-abelian finitely generated free group . In particular, we exhibit a free group in of rank which is conjugate to a proper subgroup of itself. This answers positively a question of Drutu and Sapir (2005). The main ingredient in our construction is a specific finite volume (non-compact) hyperbolic 3-manifold which is a surface bundle over the circle. In particular, most of comes from the fundamental group of a surface fiber. A key feature of is that there is an element of in with an eigenvalue which is the square root of a rational integer. We also use the Bass-Serre tree of a field with a discrete valuation to show that the group we construct is actually free.
3.
Michael Schlosser 《Proceedings of the American Mathematical Society》2002,130(4):1113-1123
We give elementary derivations of some classical summation formulae for bilateral (basic) hypergeometric series. In particular, we apply Gauß' summation and elementary series manipulations to give a simple proof of Dougall's summation. Similarly, we apply Rogers' nonterminating summation and elementary series manipulations to give a simple proof of Bailey's very-well-poised summation. Our method of proof extends M. Jackson's first elementary proof of Ramanujan's summation.
4.
Narutaka Ozawa 《Proceedings of the American Mathematical Society》2004,132(2):487-490
Gromov constructed uncountably many pairwise nonisomorphic discrete groups with Kazhdan's property . We will show that no separable -factor can contain all these groups in its unitary group. In particular, no separable -factor can contain all separable -factors in it. We also show that the full group -algebras of some of these groups fail the lifting property.
5.
J. J. Betancor B. J. Gonzá lez 《Proceedings of the American Mathematical Society》2001,129(1):219-228
In this paper we introduce new function spaces that are denoted by , -1/2$"> and and that are spaces of type where the Hankel convolution and the Hankel transformation are defined. The spaces will play the same role in the Hankel setting that the spaces play in the theory of Fourier transformation. 相似文献
6.
S. Mrowka 《Proceedings of the American Mathematical Society》2000,128(12):3701-3709
Answering a question of Arhangel'skii, we show - under GCH - that for most cardinals there exists an -compact space such that but does not embed in a closed fashion into the product of copies of .
7.
Masahiro Shioya 《Proceedings of the American Mathematical Society》2006,134(6):1819-1821
Let be a -supercompact cardinal. We show that carries a normal ultrafilter with a property introduced by Menas. With it we give a transparent proof of Kamo's theorem that carries a normal ultrafilter with the partition property.
8.
Jon P. Bannon 《Proceedings of the American Mathematical Society》2005,133(3):835-840
We introduce a notion of transitive family of subspaces relative to a type factor, and hence a notion of transitive family of projections in such a factor. We show that whenever is a factor of type and is generated by two self-adjoint elements, then contains a transitive family of projections. Finally, we exhibit a free transitive family of projections that generate a factor of type .
9.
Mó nika Bagota Ferenc Mó ricz 《Proceedings of the American Mathematical Society》2002,130(9):2617-2623
We extend from single to double Fourier series a theorem of Zygmund to determine the generalized jumps of a periodic integrable function at a simple discontinuity point. As a by-product of the proof, we obtain an estimate of the fourth mixed partial derivative of the Abel-Poisson mean of any integrable function at such a point where is smooth. We also consider the extension of the Zygmund classes and to the two-dimensional torus .
10.
Antonio Aizpuru Francisco Javier Garcia-Pacheco 《Proceedings of the American Mathematical Society》2006,134(7):2109-2115
The aim of this paper is to study the set of all -summand vectors of a real Banach space . We provide a characterization of -summand vectors in smooth real Banach spaces and a general decomposition theorem which shows that every real Banach space can be decomposed as an -sum of a Hilbert space and a Banach space without nontrivial -summand vectors. As a consequence, we generalize some results and we obtain intrinsic characterizations of real Hilbert spaces.