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401.
V. A. Roman’kov 《Siberian Mathematical Journal》2005,46(3):527-534
We show that the averaged Dehn function with respect to each finite presentation of an arbitrary finitely generated class 2 nilpotent group is subcubic. For the finite rank 2 free class 2 nilpotent group this implies the subasymptoticity of the averaged Dehn function in the sense of M. Gromov, confirming his conjecture.Original Russian Text Copyright © 2005 Romankov V. A.The author was supported by the Russian Foundation for Basic Research (Grant 04-01-00489) and the Scientific Program Universities of Russia of the Ministry for Education of the Russian Federation (Grant 362-05).__________Translated from Sibirskii Matematicheskii Zhurnal, Vol. 46, No. 3, pp. 663–672, May–June, 2005. 相似文献
402.
Let \({\cal O}\) be a nilpotent orbit in ?? where G is a compact, simple group and ? = Lie(G). It is known that \({\cal O}\) carries a unique G-invariant hyperKähler metric admitting a hyperKähler potential compatible with the Kirillov–Kostant–Souriau symplectic form. In this work, the hyperKähler potential is explicitly calculated when \({\cal O}\) is of cohomogeneity three under the action of G. It is found that such a structure lies on a one-parameter family of hyperKähler metrics with G-invariant Kähler potentials if and only if ? is Sp3, su6, So7, So12 or e7 and otherwise is the unique G-invariant hyperKähler metric with G-invariant Kähler potential. 相似文献
403.
This paper identifies a certain class of locally supersoluble groups (called soluble hall-T groups) which contains the soluble T-groups as well as the nilpotent groups. The main result states that the product of a normal soluble hall-T subgroup and a subnormal locally supersoluble subgroup is always locally supersoluble.AMS Subject Classification (1991): 20E25, 20F16, 20F19 相似文献
404.
Mohammed Guediri 《Transactions of the American Mathematical Society》2003,355(2):775-786
The main purpose of this paper is to prove that there are no closed timelike geodesics in a (compact or noncompact) flat Lorentz 2-step nilmanifold where is a simply connected 2-step nilpotent Lie group with a flat left-invariant Lorentz metric, and a discrete subgroup of acting on by left translations. For this purpose, we shall first show that if is a 2-step nilpotent Lie group endowed with a flat left-invariant Lorentz metric then the restriction of to the center of is degenerate. We shall then determine all 2-step nilpotent Lie groups that can admit a flat left-invariant Lorentz metric. We show that they are trivial central extensions of the three-dimensional Heisenberg Lie group . If is one such group, we prove that no timelike geodesic in can be translated by an element of By the way, we rediscover that the Heisenberg Lie group admits a flat left-invariant Lorentz metric if and only if
405.
406.
We show how the so called right and left determinants can be used in the solution of certain systems of linear equations over Lie niipotent rings, A close analogue of Cramer's rule is formulated for right linear equations over the Grassmann algebra. 相似文献
407.
It is shown that for exponential Lie groupsG the limit behavior of i.i.d. triangular arrays on the groupG and on the tangent spaceG coincide. This result is used to obtain a characterization of domains of partial attraction (resp. semistable attraction) on exponential (resp. simply connected nilpotent) Lie groups via the corresponding domains on the tangent space. 相似文献
408.
A. N. Dranishnikov 《Geometriae Dedicata》2006,119(1):1-15
We show that finitely generated groups with a polynomial dimension growth have Yu’s property A and give an example of such groups. 相似文献
409.
Siberian Mathematical Journal - We prove that every free nonabelian group has a finitely generated isolated subgroup not separable in the class of nilpotent groups. This enables us to give a... 相似文献
410.
结合环中的环的幂零性不是根性质。为此,本文将结合环中的幂零理想概念扩展为次拟幂零理想和拟幂零理想,定义次拟幂零根SN和拟幂零根QN,证明它们均为Amitsur-Kurosh根,且二者相等,进一步,我们给出了QN-半单环的构造命题和QN-根的模刻划。 相似文献