共查询到20条相似文献,搜索用时 31 毫秒
1.
ZuoLIU ZhenDeWU 《数学学报(英文版)》2005,21(2):409-412
Let J.^r ,k denote the ideal in MO. of cobordism classes containing a representative that admits (Z2)^k-actions with a fixed point set of constant codimension r. In this paper we determine J,k^2k 2 and Ja,3^2^3 1. 相似文献
2.
YUANJINJIANG LINYIXUN 《高校应用数学学报(英文版)》1998,13(4):451-454
The paper proves that it G is a k-tree, then the bandwidth B(^-G) of the complement ^-G of G given byB(^-G)=n-k-1,when G≈Kk-^Kn-k,n-k-2,otherwise. 相似文献
3.
Xiu Min REN Kai Man TSANG 《数学学报(英文版)》2007,23(2):265-280
In this paper, it is proved that with at most O(N65/66) exceptions, all even positive integers up to N are expressible in the form p^2 2+p^3 3+p^4 4+p^5 5. This improves a recent result O(N19193/19200+ε) due to C. Bauer. 相似文献
4.
GuiQiaoXU YongPingLIU 《数学学报(英文版)》2004,20(1):81-92
This paper concerns the problem of average σ-width of Sobolev-Wiener classes W^rpq(R^d),W^rpq(M,R^d),and Besov-Wiener classes S^rpqθb(R^d).S^rpqθB(R^d),S^rpqθb(M,R^d),S^rpqθB(R^d)in the metric Lq(R^d) for 1≤q≤p≤∞.The weak asymptotic results concerning the average linear widths,the average Bernstein widths and the infinite-dimensional Gel‘fand widths are obtained,respectively. 相似文献
5.
The convergence rates of regularized solutions of nonlinear ill-posed operator equations involving monotone operators are
investigated, and conditions that guarantee convergence rates like
and
are given, where δ denotes the noise level of the data perturbation.
Project supported by the National Natural Science Foundation of China (Grant No. 19671029). 相似文献
6.
With the aids of variational method and concentration-compactness principle, infinitely many solutions are obtained for a class of fourth order elliptic equations with singular potential
Δ^2u=μ|u|^2**(s)-2u/|x|^s+λk(x)|u|^r-2 u, u∈H^2,2(R^N) (P) 相似文献
Δ^2u=μ|u|^2**(s)-2u/|x|^s+λk(x)|u|^r-2 u, u∈H^2,2(R^N) (P) 相似文献
7.
Shi Jin DING Qiang DU 《数学学报(英文版)》2006,22(2):469-476
In this paper, we discuss the vortex structure of the superconducting thin films placed in a magnetic field. We show that the global minimizer of the functional modelling the superconducting thin films has a bounded number of vortices when the applied magnetic field hex 〈 Hc1 + K log | logε| where Hc1 is the lower critical field of the film obtained by Ding and Du in SIAM J. Math. Anal., 2002. The locations of the vortices are also given. 相似文献
8.
Ming Qiang WANG Xian Meng MENG 《数学学报(英文版)》2006,22(5):1329-1342
In this paper we prove that, with at most O(N^5/12+ε) exceptions, all positive odd integers n ≤ N with n ≡ 0 or 1(mod 3) can be written as a sum of a prime and two squares of primes. 相似文献
9.
John W. Snow 《Algebra Universalis》2008,58(1):59-71
We prove that if is a finite algebra which satisfies a nontrivial idempotent Mal’cev condition, and if Con contains a copy of an order polynomially complete lattice other than , , or Con, then Con is not hereditary.
Received March 7, 2006; accepted in final form December 5, 2006. 相似文献
10.
Let T = U|T| be the polar decomposition of a bounded linear operator T on a Hilbert space. The transformation T = |T|^1/2 U|T|^1/2 is called the Aluthge transformation and Tn means the n-th Aluthge transformation. Similarly, the transformation T(*)=|T*|^1/2 U|T*|&1/2 is called the *-Aluthge transformation and Tn^(*) means the n-th *-Aluthge transformation. In this paper, firstly, we show that T(*) = UV|T^(*)| is the polar decomposition of T(*), where |T|^1/2 |T^*|^1/2 = V||T|^1/2 |T^*|^1/2| is the polar decomposition. Secondly, we show that T(*) = U|T^(*)| if and only if T is binormal, i.e., [|T|, |T^*|]=0, where [A, B] = AB - BA for any operator A and B. Lastly, we show that Tn^(*) is binormal for all non-negative integer n if and only if T is centered, and so on. 相似文献
11.
Guang Shi Lü 《数学学报(英文版)》2006,22(3):907-916
In this paper we sharpen Hua's result by proving that each sufficiently large integer N congruent to 5 modulo 24 can be written as N=p1^2+p2^2+p3^2+p4^2+p5^2,with │pj-√N/5│≤U=N^1/2-1/28+ε,where pj are primes. 相似文献
12.
Xiu Gui LIU 《数学学报(英文版)》2007,23(3):385-392
In this paper, some groups Ext A^s.t (Zp, Zp) with specialized s and t are first computed by the May spectrM sequence. Then we make use of the Adams spectral sequence to prove the existence of a new nontrivial family of filtration s+5 in the stable homotopy groups of spheres πpnq+(s+3)pq+(s+1)q-5S which is represented (up to a nonzero scalar) by β+2bohh∈ExtA^s+5,P^nq+(n+3)pq+(n+1)q+s(Zp, Zp) in the Adams spectral sequence, where p ≥ 5 is a prime number, n ≥3, 0≤ s 〈 p - 3, q = 2(p - 1). 相似文献
13.
We consider the zeroes of the random Gaussian entire function
(
, . . . are Gaussian i.i.d. complex random variables) and show that their basins under the gradient flow of the random potential
partition the complex plane into domains of equal area.
We find three characteristic exponents 1, 8/5, and 4 of this random partition: the probability that the diameter of a particular
basin is greater than R is exponentially small in R; the probability that a given point z lies at a distance larger than R from the zero, it is attracted to decays as
; and the probability that, after throwing away 1% of the area of the basin, its diameter is still larger than R decays as
.
We also introduce a combinatorial procedure that modifies a small portion of each basin in such a way that the probability
that the diameter of a particular modified basin is greater than R decays as
.
F.N. and A.V. partially supported by the National Science Foundation, DMS grant 0501067. M.S. partially supported by the Israel
Science Foundation of the Israel Academy of Sciences and Humanities, grant 357/04.
Received: May 2006 Revision: February 2007 Accepted: March 2007 相似文献
14.
Xiu Gui LIU 《数学学报(英文版)》2007,23(6):1025-1032
Abstract Let A be the mod p Steenrod algebra and S the sphere spectrum localized at p, where p is an odd prime. In 2001 Lin detected a new family in the stable homotopy of spheres which is represented by (b0hn-h1bn-1)∈ ExtA^3,(p^n+p)q(Zp,Zp) in the Adams spectral sequence. At the same time, he proved that i.(hlhn) ∈ExtA^2,(p^n+P)q(H^*M, Zp) is a permanent cycle in the Adams spectral sequence and converges to a nontrivial element ξn∈π(p^n+p)q-2M. In this paper, with Lin's results, we make use of the Adams spectral sequence and the May spectral sequence to detect a new nontrivial family of homotopy elements jj′j^-γsi^-i′ξn in the stable homotopy groups of spheres. The new one is of degree p^nq + sp^2q + spq + (s - 2)q + s - 6 and is represented up to a nonzero scalar by hlhnγ-s in the E2^s+2,*-term of the Adams spectral sequence, where p ≥ 7, q = 2(p - 1), n ≥ 4 and 3 ≤ s 〈 p. 相似文献
15.
Gensun Fang 《中国科学A辑(英文版)》1998,41(12):1272-1277
The Nikolskii type inequality for cardinal splines
is proved, which is exact in the sense of order, where ∈ ℒ
m,h
, and ℒ
m,k
is the space of cardinal splines with nodes
Project supported by the National Natural Science Foundation of China (Grant No. 19671012), and Doctoral Programme Foundation
of Institution of Higher Education. 相似文献
16.
Lorenz J. Schwachhöfer 《Archiv der Mathematik》2008,90(2):158-162
We show that a left invariant metric on a compact Lie group G with Lie algebra has some negative sectional curvature if it is obtained by enlarging a biinvariant metric on a subalgebra , unless the semi-simple part of is an ideal of This answers a question raised in [8].
Received: 7 May 2007 相似文献
17.
We show that the traveling salesman problem with triangle inequality cannot be approximated with a ratio better than
when the edge lengths are allowed to be asymmetric and
when the edge lengths are symmetric, unless P=NP. The best previous lower bounds were
and
respectively. The reduction is from H?stad’s maximum satisfiability of linear equations modulo 2, and is nonconstructive.
* Supported in part by NSF ITR Grant CCR-0121555.
† Supported by NSF award CCR-0307536 and a Sloan foundation fellowship. 相似文献
18.
Dong Sheng Kang 《数学学报(英文版)》2009,25(3):435-444
Suppose Ω belong to R^N(N≥3) is a smooth bounded domain,ξi∈Ω,0〈ai〈√μ,μ:=((N-1)/2)^2,0≤μi〈(√μ-ai)^2,ai〈bi〈ai+1 and pi:=2N/N-2(1+ai-bi)are the weighted critical Hardy-Sobolev exponents, i = 1, 2,..., k, k ≥ 2. We deal with the conditions that ensure the existence of positive solutions to the multi-singular and multi-critical elliptic problem ∑i=1^k(-div(|x-ξi|^-2ai△↓u)-μiu/|x-ξi|^2(1+ai)-u^pi-1/|x-ξi|^bipi)=0with Dirichlet boundary condition, which involves the weighted Hardy inequality and the weighted Hardy-Sobolev inequality. The results depend crucially on the parameters ai, bi and #i, i -- 1, 2,..., k. 相似文献
19.
ZhongWei Tang 《中国科学A辑(英文版)》2008,51(9):1609-1618
Let Ω RN be a ball centered at the origin with radius R > 0 and N 7, 2* = 2N/N-2. We obtain the existence of infinitely many radial solutions for the Dirichlet problem -△u = μ |x|2 u |u|2*-2u λu in Ω, u = 0 on аΩ for suitable positive numbers μ and λ. Such solutions are characterized by the number of their nodes. 相似文献
20.
A CDCSL algebra is a reflexive operator algebra with completely distributive and commutative subspace lattice. In this paper,
we show, for a weakly closed linear subspace
of a CDCSL algebra
, that
is a Lie ideal if and only if
for all invertibles A in
, and that
is a Jordan ideal if and only if it is an associative ideal. 相似文献