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排序方式: 共有369条查询结果,搜索用时 339 毫秒
31.
32.
Shmuel Rosset 《Israel Journal of Mathematics》1991,73(3):257-279
The Baer invariants Γ
n
(G) of a group are central extensions of the elementsγ
n
(G) of the lower central series. We show that the inclusionsγ
n
+1 ⊂γ
n
can be lifted to functor morphisms Γ
n+1→Γ
n
and a canonical Lie algebra, analogous to Lazard’s Lie algebra, can be constructed which is explicitly computable. This is
applied in various ways. 相似文献
33.
Erik Guentner Nigel Higson Shmuel Weinberger 《Publications Mathématiques de L'IHéS》2005,101(1):243-268
Let K be a field. We show that every countable subgroup of GL(n,K) is uniformly embeddable in a Hilbert space. This implies that Novikov’s higher signature conjecture holds for these groups. We also show that every countable subgroup of GL(2,K) admits a proper, affine isometric action on a Hilbert space. This implies that the Baum-Connes conjecture holds for these groups. Finally, we show that every subgroup of GL(n,K) is exact, in the sense of C*-algebra theory. 相似文献
34.
We prove the conjecture of Falikman-Friedland-Loewy on the parity of the degrees of projective varieties of n×n complex symmetric matrices of rank at most k. We also characterize the parity of the degrees of projective varieties of n×n complex skew symmetric matrices of rank at most 2p. We give recursive relations which determine the parity of the degrees of projective varieties of m×n complex matrices of rank at most k. In the case the degrees of these varieties are odd, we characterize the minimal dimensions of subspaces of n×n skew symmetric real matrices and of m×n real matrices containing a nonzero matrix of rank at most k. The parity questions studied here are also of combinatorial interest since they concern the parity of the number of plane partitions contained in a given box, on the one hand, and the parity of the number of symplectic tableaux of rectangular shape, on the other hand. 相似文献
35.
Analytic families of semigroups 总被引:1,自引:0,他引:1
Shmuel Kantorovitz 《Semigroup Forum》1997,54(1):356-363
The Cauchy Problem for linear partial differential equations with coefficients depending analytically on a parameter, motivates
the study of analytic families of infinitesimal generators of semigroups. The relations between the three natural ways to
understand “analyticity” of the family are clarified. This is then applied to obtain some general results on the stability
of the analyticity of the family under perturbations of the generators. 相似文献
36.
Thermal Effects and Structural Changes of Photosynthetic Reaction Centers Characterized by Wide Frequency Band Hydrophone: Effects of Carotenoids and Terbutryn 下载免费PDF全文
László Nagy Vladimir Kiss Vlad Brumfeld Károly Osvay Ádám Börzsönyi Melinda Magyar Tibor Szabó Márta Dorogi Shmuel Malkin 《Photochemistry and photobiology》2015,91(6):1368-1375
Photothermal characteristics and light‐induced structural (volume) changes of carotenoid‐containing and noncontaining photosynthetic reaction centers (RCs) were investigated by wide frequency band hydrophone. We found that the presence of carotenoid either does not play considerable role in the light‐induced conformational movements, or these rearrangements are too slow for inducing a photoacoustic (PA) signal. The kinetic component with a few tens of microseconds, exhibited by the carotenoid‐less RCs, appears to be similar to that of triplet state lifetimes, identified by other methods. The binding of terbutryn to the acceptor side is shown to affect the dynamics of the RC. Our results do not confirm large displacements or volume changes induced by the charge movements and by the charge relaxation processes in the RCs in few hundreds of microseconds time scale that accompanies the electron transfer between the primary and secondary electron acceptor quinones. 相似文献
37.
We compute the homology of random ?ech complexes over a homogeneous Poisson process on the d‐dimensional torus, and show that there are, coarsely, two phase transitions. The first transition is analogous to the Erd?s ‐Rényi phase transition, where the ?ech complex becomes connected. The second transition is where all the other homology groups are computed correctly (almost simultaneously). Our calculations also suggest a finer measurement of scales, where there is a further refinement to this picture and separation between different homology groups. © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 51, 14–51, 2017 相似文献
38.
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40.
In this paper we consider the solution of certain convex integer minimization problems via greedy augmentation procedures.
We show that a greedy augmentation procedure that employs only directions from certain Graver bases needs only polynomially
many augmentation steps to solve the given problem. We extend these results to convex N-fold integer minimization problems and to convex 2-stage stochastic integer minimization problems. Finally, we present some
applications of convex N-fold integer minimization problems for which our approach provides polynomial time solution algorithms. 相似文献