共查询到20条相似文献,搜索用时 46 毫秒
1.
Takuzo Okada 《Mathematische Annalen》2009,345(1):195-212
We show that the family of (-factorial and log terminal) -Fano n-folds with Picard number one is birationally unbounded for n ≥ 6.
T. Okada is partially supported by JSPS Research Fellowships for Young Scientists. 相似文献
2.
Satoshi Murai 《Journal of Algebraic Combinatorics》2008,27(3):383-398
In this paper, we will show that the color-squarefree operation does not change the graded Betti numbers of strongly color-stable
ideals. In addition, we will give an example of a nonpure balanced complex which shows that colored algebraic shifting, which
was introduced by Babson and Novik, does not always preserve the dimension of reduced homology groups of balanced simplicial
complexes.
The author is supported by JSPS Research Fellowships for Young Scientists. 相似文献
3.
Tatsuya Watanabe 《NoDEA : Nonlinear Differential Equations and Applications》2008,15(3):387-412
In this paper, we study a two-dimensional nonlinear elliptic equation:
where V (x) is radial, V (x) behaves like near zero and the nonlinearity f is asymptotically linear at infinity. We show the existence of a nontrivial radial solution of (1.1) via the variational
approach.
Supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists 相似文献
4.
Let S be a compact, connected, orientable surface of positive genus. Let
be the Hatcher-Thurston complex of S. We prove that Aut
is isomorphic to the extended mapping class group of S modulo its center.
The first author is supported by a Rackham Faculty Fellowship, Horace H. Rackham School of Graduate Studies, University of
Michigan.
The second author is supported in part by the Turkish Academy of Sciences under the Young Scientists Award Program (MK/TüBA-GEBİP
2003-10). 相似文献
5.
Ligia L. Cristea Josef Dick Gunther Leobacher Friedrich Pillichshammer 《Numerische Mathematik》2007,105(3):413-455
In this paper we investigate multivariate integration in reproducing kernel Sobolev spaces for which the second partial derivatives
are square integrable. As quadrature points for our quasi-Monte Carlo algorithm we use digital (t,m,s)-nets over which are randomly digitally shifted and then folded using the tent transformation. For this QMC algorithm we show that the
root mean square worst-case error converges with order for any ɛ > 0, where 2
m
is the number of points. A similar result for lattice rules has previously been shown by Hickernell.
Ligia L. Cristea is supported by the Austrian Research Fund (FWF), Project P 17022-N 12 and Project S 9609.
Josef Dick is supported by the Australian Research Council under its Center of Excellence Program.
Gunther Leobacher is supported by the Austrian Research Fund (FWF), Project S 8305.
Friedrich Pillichshammer is supported by the Austrian Research Fund (FWF), Project P 17022-N 12, Project S 8305 and Project
S 9609. 相似文献
6.
In this paper we offer a computational approach to the spectral function for a finite family of commuting operators, and give
applications. Motivated by questions in wavelets and in signal processing, we study a problem about spectral concentration
of integral translations of functions in the Hilbert space . Our approach applies more generally to families of n arbitrary commuting unitary operators in a complex Hilbert space , or equivalent the spectral theory of a unitary representation U of the rank-n lattice in . Starting with a non-zero vector , we look for relations among the vectors in the cyclic subspace in generated by ψ. Since these vectors involve infinite “linear combinations,” the problem arises of giving geometric characterizations of these non-trivial linear
relations. A special case of the problem arose initially in work of Kolmogorov under the name L
2-independence. This refers to infinite linear combinations of integral translates of a fixed function with l
2-coefficients. While we were motivated by the study of translation operators arising in wavelet and frame theory, we stress
that our present results are general; our theorems are about spectral densities for general unitary operators, and for stochastic
integrals.
Work supported in part by the U.S. National Science Foundation. 相似文献
7.
Given the f-vector f = (f0, f1, . . .) of a Cohen–Macaulay simplicial complex, it will be proved that there exists a shellable simplicial complex Δf with f(Δf) = f such that, for any Cohen–Macaulay simplicial complex Δ with f(Δ) = f, one has
for all i and j, where f(Δ) is the f-vector of Δ and where β
ij
(I
Δ) are graded Betti numbers of the Stanley–Reisner ideal I
Δ of Δ.
The first author is supported by JSPS Research Fellowships for Young Scientists.
Received: 23 January 2006 相似文献
8.
Mikhail Chebotar Wen-Fong Ke Victor Lomonosov 《Integral Equations and Operator Theory》2008,62(4):579-584
Let be a Jordan algebra of linear operators on a vector space over a field of characteristic different from 2. In this short
note, we show that (1) if is 2-transitive, then it is dense, and (2) if is n-transitive, n ≥ 1, then a nonzero Jordan ideal of is also n-transitive. These answer two questions posed by Grünenfelder, Omladič and Radjavi.
The second author was partially supported by National Science Council, Taiwan, grant #095- 2811-M-006-005. 相似文献
9.
Shunsuke Yamana 《Mathematische Annalen》2009,344(4):853-862
We prove that Siegel modular forms of degree greater than one, integral weight and level N, with respect to a Dirichlet character of conductor are uniquely determined by their Fourier coefficients indexed by matrices whose contents run over all divisors of . The cases of other major types of holomorphic modular forms are included.
The author is supported by the Grant-in-Aid for JSPS fellows. 相似文献
10.
11.
Given a self-adjoint semigroup e−tA
satisfying an ultracontractivity bound of the type , we find conditions on the sequence that imply that f is a bounded function. Sobolev’s classical embedding theorem says that, when A is the Laplace operator on , for some k > d/4 suffices to imply that f is bounded. In the cases we are interested in, the desired condition involves the whole sequence and depends on the behavior of the ultracontractivity function m.
Research of A. Bendikov was supported by the Polish Goverment Scientific Research Fund, Grant 1 PO3 A 03129. Research of T.
Coulhon was partially supported by the European Commission (IHP Network “Harmonic Analysis and Related Problems” 2002–2006,
Contract HPRN-CT-2001-00273-HARP). Research of L. Saloff-Coste was partially supported by NSF grant DMS-0102126. 相似文献
12.
The lattice vertex operator algebra VL associated to a positive definite even lattice L has an automorphism of order 2 lifted from –1-isometry of L. The fixed point set VL+ of VL for the automorphism is naturally a vertex operator algebra. We prove that any 0-graded weak VL+-module is completely reducible.Supported by JSPS Research Fellowships for Young Scientists. 相似文献
13.
In this paper, we introduce Property ∏σ of operator algebras and prove that nest subalgebras and the finite-width CSL subalgebras of arbitrary von Neumann algebras have Property ∏σ.Finally, we show that the tensor product formula alg ML1-(×)algNL2 = algM-(×)N(L1 (×) L2) holds for any two finite-width CSLs L1 and L2 in arbitrary von Neumann algebras M and N, respectively. 相似文献
14.
15.
Bakhadyr Khoussainov Theodore Slaman Pavel Semukhin 《Archive for Mathematical Logic》2006,45(6):769-781
In this paper we study the question as to which computable algebras are isomorphic to non-computable -algebras. We show that many known algebras such as the standard model of arithmetic, term algebras, fields, vector spaces and torsion-free abelian groups have non-computable-presentations. On the other hand, many of this structures fail to have non-computable -presentation.This research was partially supported by the Marsden Fund of New Zealand. The third author’s research was partially supported by RFFR grant No. 02-01-00593 and Council for Grants under RF President, project NSh-2112.2003.1. 相似文献
16.
New variational principles based on the concept of anti-selfdual (ASD) Lagrangians were recently introduced in “AIHP-Analyse
non linéaire, 2006”. We continue here the program of using such Lagrangians to provide variational formulations and resolutions
to various basic equations and evolutions which do not normally fit in the Euler-Lagrange framework. In particular, we consider
stationary boundary value problems of the form as well ass dissipative initial value evolutions of the form where is a convex potential on an infinite dimensional space, A is a linear operator and is any scalar. The framework developed in the above mentioned paper reformulates these problems as and respectively, where is an “ASD” vector field derived from a suitable Lagrangian L. In this paper, we extend the domain of application of this approach by establishing existence and regularity results under
much less restrictive boundedness conditions on the anti-selfdual Lagrangian L so as to cover equations involving unbounded operators. Our main applications deal with various nonlinear boundary value
problems and parabolic initial value equations governed by transport operators with or without a diffusion term.
Nassif Ghoussoub research was partially supported by a grant from the Natural Sciences and Engineering Research Council of
Canada. The author gratefully acknowledges the hospitality and support of the Centre de Recherches Mathématiques in Montréal
where this work was initiated.
Leo Tzou’s research was partially supported by a doctoral postgraduate scholarship from the Natural Science and Engineering
Research Council of Canada. 相似文献
17.
Yukihiro Tsutsumi 《Mathematische Zeitschrift》2004,246(1-2):167-175
A method for constructing hyperbolic knots each of which bounds accidental incompressible Seifert surfaces of arbitrarily high genus is given.
Mathematics Subject Classification (2000):57N10, 57M25.The author was supported in part by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists. 相似文献
18.
Trieu Le 《Integral Equations and Operator Theory》2007,59(4):555-578
Using the joint local mean oscillation, Jingbo Xia [13] showed that the essential commutant of , where is the subalgebra of L
∞ generated by all functions which are bounded and have at most one discontinuity, is (QC). Even though Xia’s method cannot be used, we are able to generalize his result to Toeplitz operators in higher dimensions
with a different approach. This result is stronger than the well-known result stating that the essential commutant of the
full Toeplitz algebra is (QC).
相似文献
19.
By constructing a holomorphic cubic form for Lagrangian surfaces with nonzero constant length mean curvature vector in a 2-dimensional
complex space form (4c), we characterize the Lagrangian pesudosphere as the only branched Lagrangian immersion of a sphere in (4c) with nonzero constant length mean curvature vector. When c = 0, our result reduces to Castro-Urbano’s result in [1].
H. Li is partially supported by NSFC grant No. 10531090
H. Ma is partially supported by NSFC grant No. 10501028 and SRF for ROCS, SEM 相似文献
20.
Let be a k-uniform hypergraph on [n] where k−1 is a power of some prime p and n≥ n
0(k). Our main result says that if , then there exists E
0∊ such that {E∩ E
0: E∊ } contains all subsets of E
0. This improves a longstanding bound of due to Frankl and Pach [7].Research supported in part by NSF grants DMS-0400812 and an Alfred P. Sloan Research Fellowship.Research supported in part by NSA grant H98230-05-1-0079. Part of this research was done while working at University of Illinois at Chicago. 相似文献