منابع مشابه
Pseudofree Representations and 2-pseudofree Actions on Spheres
We characterize 1-pseudofree real representations of finite groups. We apply this to show that the representations at fixed points of a 2-pseudofree smooth action of a finite group on a sphere of dimension > 5 are topologically equivalent. Moreover with one possible exception, the sphere is Ghomeomorphic to a linear representation sphere.
متن کاملComputable Completely Decomposable Groups
A completely decomposable group is an abelian group of the form ⊕ i Hi, where Hi ≤ (Q,+). We show that every computable completely decomposable group is ∆5-categorical. We construct a computable completely decomposable group which is not ∆4-categorical, and give an example of a computable completely decomposable group G which is ∆4-categorical but not ∆3-categorical. We also prove that the inde...
متن کاملPseudofree Group Actions on Spheres
R. S. Kulkarni showed that a finite group acting pseudofreely, but not freely, preserving orientation, on an even-dimensional sphere (or suitable sphere-like space) is either a periodic group acting semifreely with two fixed points, a dihedral group acting with three singular orbits, or one of the polyhedral groups, occurring only in dimension 2. It is shown here that the dihedral group does no...
متن کاملOn the Structure Groups of Decomposable Algebraic Curvature Tensors
This paper examines the action of GLN (R) on decomposable algebraic curvature tensors. The main result is that the structure group of a decomposable algebraic curvature tensor can only permute the subspaces into which the tensor decomposes: if the tensor decomposes into tensors Ri on Vi where V = ⊕k i=1 Vi, then for any matrix A in the structure group there exists a permutation σ such that A : ...
متن کاملNonsurjective epimorphisms in decomposable varieties of groups
A full characterization of when a subgroup H of a group G in a varietal product NQ is epimorphically embedded in G (in the variety NQ ) is given. From this, a result of S. McKay is derived , which states that if NQ has instances of nonsurjective epimorphisms, then N also has instances of nonsurjective epimorphisms. Two partial converses to McKay’s result are also given: when G is a finite nonab...
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ژورنال
عنوان ژورنال: International Journal of Mathematics and Mathematical Sciences
سال: 1999
ISSN: 0161-1712,1687-0425
DOI: 10.1155/s0161171299226178