年代:1990 |
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Volume 22 issue 6
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1. |
A Remark on the Homogeneity of infinite Permutation Groups |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 529-532
A. Hajnal,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.529
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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2. |
Constructions of Partial Difference Sets and Relative Difference Sets onp‐Groups |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 533-539
Ka Hin Leung,
Siu Lun Ma,
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摘要:
By using some finite local rings, we construct some new partial difference sets and relative difference sets onpgroups wherepis any prime. Whenp= 2, some of partial difference sets constructed are reversible difference sets which include Dillon's difference sets.
ISSN:0024-6093
DOI:10.1112/blms/22.6.533
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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3. |
The Representation Type of Self‐Injective Algebras |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 540-546
Jeremy Rickard,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.540
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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4. |
Euler Characteristics of Real Varieties |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 547-552
J. W. Bruce,
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摘要:
In this paper we show how to associate to any real projective algebraic varietyZ⊂RPn−1a real polynomialF1:Rn,0 →R, 0 with an algebraically isolated singularity, having the property that χ(Z) = ½(1 − deg (gradF1), where deg (gradF1is the local real degree of the gradient gradF1:Rn, 0 →Rn, 0. This degree can be computed algebraically by the method of Eisenbud and Levine, and Khimshiashvili [5]. The varietyZneed not be smooth.This leads to an expression for the Euler characteristic of any compact algebraic subset ofRn, and the link of a quasihomogeneous mappingf:Rn, 0 →Rn, 0 again in terms of the local degree of a gradient with algebraically isolated singularity.Similar expressions for the Euler characteristic of an arbitrary algebraic subset ofRnand the link of any polynomial map are given in terms of the degrees of algebraically finite gradient maps. These maps do involve ‘sufficiently small’ constants, but the degrees involved ar (theoretically, at least) algebraically computable.
ISSN:0024-6093
DOI:10.1112/blms/22.6.547
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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5. |
A Note on Groups Associated with 4‐Arc‐Transitive Cubic Graphs |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 553-560
Marston Conder,
Margaret Morton,
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摘要:
A cubic (trivalent) graph Γ is said to be 4‐arc‐transitive if its automorphism group acts transitively on the 4‐arcs of Γ (where a 4‐arc is a sequencev0,v1, …v4of vertices of Γ such thatvi−1is adjacent tovifor 1 ⩽i⩽ 4, andvi−1≠vi+1for 1 ⩽i<4). In his investigations into graphs of this sort, Biggs defined a family of groups 4+(am), form= 3,4,5…, each presented in terms of generators and relations under the additional assumption that the vertices of a circuit of lengthmare cyclically permuted by some automorphism. In this paper it is shown that whenevermis a proper multiple of 6, the group 4+(am) is infinite. The proof is obtained by constructing transitive permutation representations of arbitrarily large degree.
ISSN:0024-6093
DOI:10.1112/blms/22.6.553
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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6. |
Supersoluble Groups of Automorphisms of Nonorientable Riemann Surfaces |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 561-568
Grzegorz Gromadzki,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.561
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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7. |
On a Graph Related to Conjugacy Classes of Groups |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 569-575
Edward A. Bertram,
Marcel Herzog,
Avinoam Mann,
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摘要:
LetGbe a finite group. Attach toGthe following graph Γ: its vertices are the non‐central conjugacy classes ofG, and two vertices are connected if their cardinalities arenotcoprime. Denote byn(Γ) the number of the connecte components of Γ. We prove thatn(Γ) ⩽ 2 for all finite groups, and we completely characterize groups withn(Γ) = 2. When Γ is connected, then the diameter of the graph is at most 4. For simple non‐abelian finite groups, the graph is complete. Similar results are proved for infinite FC‐groups.
ISSN:0024-6093
DOI:10.1112/blms/22.6.569
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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8. |
Symmetries of Julia Sets |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 576-582
A. F. Beardon,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.576
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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9. |
Construction of a Thin Set with small Fourier Coefficients |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 583-590
Miklós Ajtai,
Henryk Iwaniec,
János Komlós,
János Pintz,
Endre Szemerédi,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.583
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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10. |
RLocal Homotopy Theory as Part of Tame Homotopy Theory |
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Bulletin of the London Mathematical Society,
Volume 22,
Issue 6,
1990,
Page 591-598
Hans Scheerer,
Daniel Tanré,
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ISSN:0024-6093
DOI:10.1112/blms/22.6.591
出版商:Oxford University Press
年代:2016
数据来源: WILEY
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