共查询到20条相似文献,搜索用时 31 毫秒
1.
Heekyoung Hahn 《Proceedings of the American Mathematical Society》2007,135(8):2391-2401
Let SL be a genus zero Fuchsian group of the first kind with as a cusp, and let be the holomorphic Eisenstein series of weight on that is nonvanishing at and vanishes at all the other cusps (provided that such an Eisenstein series exists). Under certain assumptions on and on a choice of a fundamental domain , we prove that all but possibly of the nontrivial zeros of lie on a certain subset of . Here is a constant that does not depend on the weight, is the upper half-plane, and is the canonical hauptmodul for
2.
Katsuhiko Matsuzaki 《Proceedings of the American Mathematical Society》2007,135(8):2573-2579
For an analytically infinite Riemann surface , the quasiconformal mapping class group always acts faithfully on the ordinary Teichmüller space . However in this paper, an example of is constructed for which acts trivially on its asymptotic Teichmüller space .
3.
Francisco-Javier Turiel 《Proceedings of the American Mathematical Society》2007,135(8):2665-2667
We construct, for every even dimensional sphere , , and every odd integer , a homogeneous polynomial map of Brouwer degree and algebraic degree .
4.
Amol Sasane 《Proceedings of the American Mathematical Society》2007,135(7):2107-2111
Let , denote the unit disc and unit circle, respectively, in , with center 0. If , then let denote the set of complex-valued functions defined on that are analytic in , and continuous and bounded on . Then is a ring with pointwise addition and multiplication. We prove that if the intersection of with the set of limit points of is not empty, then the ring is not coherent.
5.
Reza Sazeedeh 《Proceedings of the American Mathematical Society》2007,135(8):2339-2345
Let be a Noetherian homogeneous ring with local base ring and let be a finitely generated graded -module. Let be the largest integer such that is not Artinian. We will prove that are Artinian for all and there exists a polynomial of degree less than such that for all . Let be the first integer such that the local cohomology module is not cofinite. We will show that for all the graded module is Artinian.
6.
M. C. Stanley 《Proceedings of the American Mathematical Society》2007,135(8):2619-2622
In , assume that is a strong limit cardinal and . Let be the set of approachable ordinals less than . An open question of M. Foreman is whether can be non-stationary in some and preserving extension of . It is shown here that if is such an outer model, then is infinite, for each positive integer .
7.
Marian Nowak 《Proceedings of the American Mathematical Society》2007,135(9):2803-2809
Let be an ideal of over a -finite measure space , and let stand for the order dual of . For a real Banach space let be a subspace of the space of -equivalence classes of strongly -measurable functions and consisting of all those for which the scalar function belongs to . For a real Banach space a linear operator is said to be order-weakly compact whenever for each the set is relatively weakly compact in . In this paper we examine order-weakly compact operators . We give a characterization of an order-weakly compact operator in terms of the continuity of the conjugate operator of with respect to some weak topologies. It is shown that if is an order continuous Banach function space, is a Banach space containing no isomorphic copy of and is a weakly sequentially complete Banach space, then every continuous linear operator is order-weakly compact. Moreover, it is proved that if is a Banach function space, then for every Banach space any continuous linear operator is order-weakly compact iff the norm is order continuous and is reflexive. In particular, for every Banach space any continuous linear operator is order-weakly compact iff is reflexive.
8.
Daria Michalik 《Proceedings of the American Mathematical Society》2007,135(8):2661-2664
We give a short proof of the following fact: the set of embeddings of any -dimensional separable metric space into a certain -dimensional subset of the -product of Sierpinski curves is residual in .
9.
Bebe Prunaru 《Proceedings of the American Mathematical Society》2007,135(11):3621-3630
A family of commuting bounded operators on a Hilbert space is said to be a spherical isometry if in the weak operator topology. We show that every commuting family of spherical isometries is jointly subnormal, which means that it has a commuting normal extension on some Hilbert space Suppose now that the normal extension is minimal. Then we show that every bounded operator in the commutant of has a unique norm preserving extension to an operator in the commutant of Moreover, if is the commutator ideal in then is *-isomorphic to We also show that the commutant of the minimal normal extension is completely isometric, via the compression mapping, to the space of Toeplitz-type operators associated to We apply these results to construct exact sequences for Toeplitz algebras on generalized Hardy spaces associated to strictly pseudoconvex domains.
10.
Esteban Andruchow Lá zaro Recht Alejandro Varela 《Proceedings of the American Mathematical Society》2007,135(8):2527-2537
We consider the problem of finding short smooth curves of isometries in a Hilbert space . The length of a smooth curve , , is measured by means of , where denotes the usual norm of operators. The initial value problem is solved: for any isometry and each tangent vector at (which is an operator of the form with ) with norm less than or equal to , there exist curves of the form , with initial velocity , which are short along their path. These curves, which we call metric geodesics, need not be unique, and correspond to the so called extension problem considered by M.G. Krein and others: in our context, given a symmetric operator find all possible extending to all , with . We also consider the problem of finding metric geodesics joining two given isometries and . It is well known that if there exists a continuous path joining and , then both ranges have the same codimension. We show that if this number is finite, then there exist metric geodesics joining and .
11.
We consider an invertible operator on a Banach space whose spectrum is an interpolating set for Hölder classes. We show that if , , with and , then for all , assuming that satisfies suitable regularity conditions. When is a Hilbert space and (i.e. is a contraction), we show that under the same assumptions, is unitary and this is sharp.
12.
Sonja Lj. Cukic Emanuele Delucchi 《Proceedings of the American Mathematical Society》2007,135(8):2403-2414
The construction of the Bier sphere for a simplicial complex is due to Bier (1992). Björner, Paffenholz, Sjöstrand and Ziegler (2005) generalize this construction to obtain a Bier poset from any bounded poset and any proper ideal . They show shellability of for the case , the boolean lattice, and thereby obtain `many shellable spheres' in the sense of Kalai (1988).
We put the Bier construction into the general framework of the theory of nested set complexes of Feichtner and Kozlov (2004). We obtain `more shellable spheres' by proving the general statement that combinatorial blowups, hence stellar subdivisions, preserve shellability.
13.
Mara D. Neusel Mü fit Sezer 《Proceedings of the American Mathematical Society》2007,135(8):2347-2354
Let be a faithful representation of a finite group . In this paper we proceed with the study of the image of the associated Noether map In our 2005 paper it has been shown that the Noether map is surjective if is a projective -module. This paper deals with the converse. The converse is in general not true: we illustrate this with an example. However, for -groups (where is the characteristic of the ground field ) as well as for permutation representations of any group the surjectivity of the Noether map implies the projectivity of .
14.
A. Giannopoulos A. Pajor G. Paouris 《Proceedings of the American Mathematical Society》2007,135(8):2599-2606
We give an alternative proof of a recent result of Klartag on the existence of almost subgaussian linear functionals on convex bodies. If is a convex body in with volume one and center of mass at the origin, there exists such that for all , where is an absolute constant. The proof is based on the study of the -centroid bodies of . Analogous results hold true for general log-concave measures.
15.
Yves Felix Steve Halperin Jean-Claude Thomas 《Proceedings of the American Mathematical Society》2007,135(5):1575-1578
Let be a connected finite type graded Lie algebra. If dim and gldim , then log index . If, moreover, , then for some , dim where log index as
16.
Oscar Blasco Paco Villarroya 《Proceedings of the American Mathematical Society》2004,132(7):1997-2004
Let , and let and denote the bilinear and linear Hilbert transforms, respectively. It is proved that, for and , maps into and it maps into if and only if . It is also shown that, for the commutator is bounded on for if and only if , where .
17.
Natan Kruglyak Eric Setterqvist 《Proceedings of the American Mathematical Society》2008,136(7):2505-2513
It is shown that if we restrict the identity minus Hardy operator on the cone of nonnegative decreasing functions in , then we have the sharp estimate for In other words, for each and each integer . for all .
It is also shown, via a connection between the operator and Laguerre functions, that
18.
Congwen Liu 《Proceedings of the American Mathematical Society》2007,135(9):2867-2876
Let denote the open unit ball in for and the Lebesgue volume measure on . For , the (weighted) harmonic Bergman space is the space of all harmonic functions which are in . For , the Toeplitz operator is defined on by , where is the orthogonal projection of onto . In this note, we prove that for radial, .
19.
Vigleik Angeltveit 《Proceedings of the American Mathematical Society》2008,136(7):2323-2332
We define the notion of an enriched Reedy category and show that if is a -Reedy category for some symmetric monoidal model category and is a -model category, the category of -functors and -natural transformations from to is again a model category.
20.
Paul J. Szeptycki 《Proceedings of the American Mathematical Society》2007,135(7):2273-2282
For a family of sets , and a set , is said to be a transversal of if and for each . is said to be a Bernstein set for if for each . Erdos and Hajnal first studied when an almost disjoint family admits a set such as a transversal or Bernstein set. In this note we introduce the following notion: a family of sets is said to admit a -transversal if can be written as such that each admits a transversal. We study the question of when an almost disjoint family admits a -transversal and related questions.