DSpace Collection: Volume 27 Number 2
http://hdl.handle.net/10525/458
Serdica Mathematical Journal Volume 27, Number 2, 2001The Collection's search engineSearch the Channelsearch
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On some Results Related to Köthe's Conjecture
http://hdl.handle.net/10525/474
Title: On some Results Related to Köthe's Conjecture<br/><br/>Authors: Agata, Smoktunowicz<br/><br/>Abstract: The Köthe conjecture states that if a ring R has no nonzero nilideals then R has no nonzero nil one-sided ideals. Although for more than70 years significant progress has been made, it is still open in general. Inthis paper we survey some results related to the Köthe conjecture as well assome equivalent problems.Mon, 01 Jan 2001 00:00:00 GMTExamples Illustrating some Aspects of the Weak Deligne-Simpson Problem
http://hdl.handle.net/10525/473
Title: Examples Illustrating some Aspects of the Weak Deligne-Simpson Problem<br/><br/>Authors: Kostov, Vladimir<br/><br/>Abstract: We consider the variety of (p + 1)-tuples of matrices Aj (resp.Mj ) from given conjugacy classes cj ⊂ gl(n, C) (resp. Cj ⊂ GL(n, C))such that A1 + . . . + A[p+1] = 0 (resp. M1 . . . M[p+1] = I). This variety isconnected with the weak Deligne-Simpson problem: give necessary and sufficient conditions on the choice of the conjugacy classes cj ⊂ gl(n, C) (resp.Cj ⊂ GL(n, C)) so that there exist (p + 1)-tuples with trivial centralizers ofmatrices Aj ∈ cj (resp. Mj ∈ Cj ) whose sum equals 0 (resp. whose productequals I). The matrices Aj (resp. Mj ) are interpreted as matrices-residuaof Fuchsian linear systems (resp. as monodromy operators of regular linearsystems) on Riemann’s sphere. We consider examples of such varieties ofdimension higher than the expected one due to the presence of (p + 1)-tupleswith non-trivial centralizers; in one of the examples the difference betweenthe two dimensions is O(n).<br/><br/>Description: Research partially supported by INTAS grant 97-1644Mon, 01 Jan 2001 00:00:00 GMTGroups with Decomposable Set of Quasinormal Subgroups
http://hdl.handle.net/10525/472
Title: Groups with Decomposable Set of Quasinormal Subgroups<br/><br/>Authors: de Falco, M.; de Giovanni, F.<br/><br/>Abstract: A subgroup H of a group G is said to be quasinormal if HX =XH for all subgroups X of G. In this article groups are characterized forwhich the partially ordered set of quasinormal subgroups is decomposable.Mon, 01 Jan 2001 00:00:00 GMTOn the 3-Colouring Vertex Folkman Number F(2,2,4)
http://hdl.handle.net/10525/471
Title: On the 3-Colouring Vertex Folkman Number F(2,2,4)<br/><br/>Authors: Nenov, Nedyalko<br/><br/>Abstract: In this note we prove that F (2, 2, 4) = 13.Mon, 01 Jan 2001 00:00:00 GMTModels of Alternating Renewal Process at Discrete Time
http://hdl.handle.net/10525/470
Title: Models of Alternating Renewal Process at Discrete Time<br/><br/>Authors: Bousseboua, Moussedek; Lazhar Rahmani, Fouad<br/><br/>Abstract: We study a class of models used with success in the modelling ofclimatological sequences. These models are based on the notion of renewal.At first, we examine the probabilistic aspects of these models to afterwardsstudy the estimation of their parameters and their asymptotical properties,in particular the consistence and the normality. We will discuss for applications,two particular classes of alternating renewal processes at discretetime. The first class is defined by laws of sojourn time that are translatednegative binomial laws and the second class, suggested by Green is deducedfrom alternating renewal process in continuous time with sojourn time lawswhich are exponential laws with parameters α^0 and α^1 respectively.Mon, 01 Jan 2001 00:00:00 GMTEquivariant Embeddings of Differentiable Spaces
http://hdl.handle.net/10525/469
Title: Equivariant Embeddings of Differentiable Spaces<br/><br/>Authors: Rivas, R.; González, J.; De Salas, J.<br/><br/>Abstract: Given a differentiable action of a compact Lie group G on acompact smooth manifold V , there exists [3] a closed embedding of V intoa finite-dimensional real vector space E so that the action of G on V maybe extended to a differentiable linear action (a linear representation) of Gon E. We prove an analogous equivariant embedding theorem for compactdifferentiable spaces (∞-standard in the sense of [6, 7, 8]).Mon, 01 Jan 2001 00:00:00 GMTBoolean Rings that are Baire Spaces
http://hdl.handle.net/10525/468
Title: Boolean Rings that are Baire Spaces<br/><br/>Authors: Haydon, R.<br/><br/>Abstract: Weak completeness properties of Boolean rings are related tothe property of being a Baire space (when suitably topologised) and torenorming properties of the Banach spaces of continuous functions on thecorresponding Stone spaces.<br/><br/>Description: ∗ The present article was originally submitted for the second volume of Murcia Seminar onFunctional Analysis (1989). Unfortunately it has been not possible to continue with MurciaSeminar publication anymore. For historical reasons the present vesion correspond with the original one.Mon, 01 Jan 2001 00:00:00 GMT