DSpace Community: 2011
http://hdl.handle.net/10525/2712
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(2,3)-generation of the groups PSL6(q)
http://hdl.handle.net/10525/2744
Title: (2,3)-generation of the groups PSL6(q)<br/><br/>Authors: Tabakov, K.; Tchakerian, K.<br/><br/>Abstract: We prove that the group PSL6(q) is (2,3)-generated for any q. In fact, we provide explicit generators x and y of orders 2 and 3, respectively, for the group SL6(q).<br/><br/>Description: 2010 Mathematics Subject Classification: 20F05, 20D06.Sat, 01 Jan 2011 00:00:00 GMTOn strongly regular graphs with m2 = qm3 and m3 = qm2
http://hdl.handle.net/10525/2743
Title: On strongly regular graphs with m2 = qm3 and m3 = qm2<br/><br/>Authors: Lepovic, Mirko<br/><br/>Abstract: We say that a regular graph G of order n and degree r і 1 (which is not the complete graph) is strongly regular if there exist non-negative integers t and q such that |SiЗSj| = t for any two adjacent vertices i and j, and |SiЗSj| = q for any two distinct non-adjacent vertices i and j, where Sk denotes the neighborhood of the vertex k. Let l1 = r, l2 and l3 be the distinct eigenvalues of a connected strongly regular graph. Let m1 = 1, m2 and m3 denote the multiplicity of r, l2 and l3, respectively. We here describe the parameters n, r, t and q for strongly regular graphs with m2 = qm3 and m3 = qm2 for q = 2, 3, 4.<br/><br/>Description: 2010 Mathematics Subject Classification: 05C50.Sat, 01 Jan 2011 00:00:00 GMTWeighted composition followed by differentiation between weighted Banach spaces of holomorphic functions
http://hdl.handle.net/10525/2742
Title: Weighted composition followed by differentiation between weighted Banach spaces of holomorphic functions<br/><br/>Authors: Wolf, Elke<br/><br/>Abstract: Let f be an analytic self-map of the open unit disk D in the complex plane and y be an analytic map on D. Such maps induce a weighted composition operator followed by differentiation DCf, y acting between weighted Banach spaces of holomorphic functions. We characterize boundedness and compactness of such operators in terms of the involved weights as well as the functions f and y.<br/><br/>Description: 2010 Mathematics Subject Classification: 47B33, 47B38.Sat, 01 Jan 2011 00:00:00 GMTGrowth of some varieties of Leibniz-Poisson algebras
http://hdl.handle.net/10525/2741
Title: Growth of some varieties of Leibniz-Poisson algebras<br/><br/>Authors: Ratseev, S. M.<br/><br/>Abstract: Let V be a variety of Leibniz-Poisson algebras over an arbitrary field whose ideal of identities contains the identities {{x1,y1},{x2,y2},ј,{xm,ym}} = 0, {x1,y1}·{x2,y2}· ј ·{xm,ym} = 0 for some m. It is shown that the exponent of V exists and is an integer.<br/><br/>Description: 2010 Mathematics Subject Classification: 17A32, 17B63.Sat, 01 Jan 2011 00:00:00 GMTEquiconvergence and equisummability of Jacobi series
http://hdl.handle.net/10525/2740
Title: Equiconvergence and equisummability of Jacobi series<br/><br/>Authors: Boychev, Georgi<br/><br/>Abstract: In this paper we give some results concerning the equiconvergence and equisummability of series in Jacobi polynomials.<br/><br/>Description: 2010 Mathematics Subject Classification: 33C45, 40G05.Sat, 01 Jan 2011 00:00:00 GMTPolynomial automorphisms over finite fields: Mimicking tame maps by the Derksen group
http://hdl.handle.net/10525/2739
Title: Polynomial automorphisms over finite fields: Mimicking tame maps by the Derksen group<br/><br/>Authors: Maubach, Stefan; Willems, Roel<br/><br/>Abstract: If F is a polynomial automorphism over a finite field Fq in dimension n, then it induces a permutation pqr(F) of (Fqr)n for every r О N*. We say that F can be "mimicked" by elements of a certain group of automorphisms G if there are gr О G such that pqr(gr) = pqr(F).Derksen's theorem in characteristic zero states that the tame automorphisms in dimension n і 3 are generated by the affine maps and the one map (x1+x22, x2,ј, xn). We show that Derksen's theorem is not true in characteristic p in general. However, we prove a modified, weaker version of Derksen's theorem over finite fields: we introduce the Derksen group DAn(Fq), n і 3, which is generated by the affine maps and one well-chosen nonlinear map, and show that DAn(Fq) mimicks any element of TAn(Fq). Also, we do give an infinite set E of non-affine maps which, together with the affine maps, generate the tame automorphisms in dimension 3 and up. We conjecture that such a set E cannot be finite.We consider the subgroups GLINn(k) and GTAMn(k). We prove that for k a finite field, these groups are equal if and only if k\not = F2. The latter result provides a tool to show that a map is not linearizable.<br/><br/>Description: 2010 Mathematics Subject Classification: 14L99, 14R10, 20B27.Sat, 01 Jan 2011 00:00:00 GMTDouble complexes and vanishing of Novikov cohomology
http://hdl.handle.net/10525/2738
Title: Double complexes and vanishing of Novikov cohomology<br/><br/>Authors: Hüttemann, Thomas<br/><br/>Abstract: We consider non-standard totalisation functors for double complexes, involving left or right truncated products. We show how properties of these imply that the algebraic mapping torus of a self map h of a cochain complex of finitely presented modules has trivial negative Novikov cohomology, and has trivial positive Novikov cohomology provided h is a quasi-isomorphism. As an application we obtain a new and transparent proof that a finitely dominated cochain complex over a Laurent polynomial ring has trivial (positive and negative) Novikov cohomology.<br/><br/>Description: 2010 Mathematics Subject Classification: Primary 18G35; Secondary 55U15.Sat, 01 Jan 2011 00:00:00 GMTOn the generalized Kato spectrum
http://hdl.handle.net/10525/2737
Title: On the generalized Kato spectrum<br/><br/>Authors: Benharrat, Mohammed; Messirdi, Bekkai<br/><br/>Abstract: We show that the symmetric difference between the generalized Kato spectrum and the essential spectrum defined in [7] by sec(T) = {l О C ; R(lI-T) is not closed } is at most countable and we also give some relationship between this spectrum and the SVEP theory.<br/><br/>Description: 2010 Mathematics Subject Classification: 47A10.Sat, 01 Jan 2011 00:00:00 GMTDirac type condition and Hamiltonian graphs
http://hdl.handle.net/10525/2736
Title: Dirac type condition and Hamiltonian graphs<br/><br/>Authors: Zhao, Kewen<br/><br/>Abstract: In 1952, Dirac introduced the degree type condition and proved that if G is a connected graph of order n і 3 such that its minimum degree satisfies d(G) і n/2, then G is Hamiltonian. In this paper we investigate a further condition and prove that if G is a connected graph of order n і 3 such that d(G) і (n-2)/2, then G is Hamiltonian or G belongs to four classes of well-structured exceptional graphs.<br/><br/>Description: 2010 Mathematics Subject Classification: 05C38, 05C45.Sat, 01 Jan 2011 00:00:00 GMTOuter endomorphisms of free metabelian Lie algebras
http://hdl.handle.net/10525/2735
Title: Outer endomorphisms of free metabelian Lie algebras<br/><br/>Authors: Findik, Sehmus<br/><br/>Abstract: Let Fm be the free metabelian Lie algebra of rank m over a field K of characteristic 0. We consider the semigroup IE(Fm) of the endomorphisms of Fm which are identical modulo the commutator ideal of Fm. We describe the factor semigroup of IE(Fm) modulo the congruence induced by the group of inner automorphisms.<br/><br/>Description: 2000 Mathematics Subject Classification: 17B01, 17B30, 17B40.Sat, 01 Jan 2011 00:00:00 GMTZolotarev's proof of Gauss reciprocity and Jacobi symbols
http://hdl.handle.net/10525/2734
Title: Zolotarev's proof of Gauss reciprocity and Jacobi symbols<br/><br/>Authors: Szyjewski, Marek<br/><br/>Abstract: We extend to the Jacobi symbol Zolotarev's idea that the Legendre symbol is the sign of a permutation, which leads to simple, strightforward proofs of many results, the proof of the Gauss Reciprocity for Jacobi symbols including.<br/><br/>Description: 2000 Mathematics Subject Classification: Primary 11A15.Sat, 01 Jan 2011 00:00:00 GMTOptimal investment under stochastic volatility and power type utility function
http://hdl.handle.net/10525/2733
Title: Optimal investment under stochastic volatility and power type utility function<br/><br/>Authors: Benchaabane, Abbes; Benchettah, Azzedine<br/><br/>Abstract: In this work we will study a problem of optimal investment in financial markets with stochastic volatility with small parameter. We used the averaging method of Bogoliubov for limited development for the optimal strategies when the small parameter of the model tends to zero and the limit for the optimal strategy and demonstrated the convergence of these optimal strategies.<br/><br/>Description: 2000 Mathematics Subject Classification: 37F21, 70H20, 37L40, 37C40, 91G80, 93E20.Sat, 01 Jan 2011 00:00:00 GMTRemarks on blow up time for solutions of a nonlinear diffusion system with time dependent coefficients
http://hdl.handle.net/10525/2732
Title: Remarks on blow up time for solutions of a nonlinear diffusion system with time dependent coefficients<br/><br/>Authors: Marras, M.<br/><br/>Abstract: We investigate the blow-up of the solutions to a nonlinear parabolic system with Robin boundary conditions and time dependent coefficients. We derive sufficient conditions on the nonlinearities and the initial data in order to obtain explicit lower and upper bounds for the blow up time t*.<br/><br/>Description: 2000 Mathematics Subject Classification: 35K55, 35K60.Sat, 01 Jan 2011 00:00:00 GMTFormes de contact ayant le même champ de Reeb
http://hdl.handle.net/10525/2731
Title: Formes de contact ayant le même champ de Reeb<br/><br/>Authors: Aggoun, Saad<br/><br/>Abstract: In this paper, we study contact forms on a 3-manifold having a common Reeb vector field R. The main result is that when the contact forms induce the same orientation, they are diffeomorphic.<br/><br/>Description: 2000 Mathematics Subject Classification: 37J55, 53D10, 53D17, 53D35.Sat, 01 Jan 2011 00:00:00 GMTSpecial compositions in affinely connected spaces without a torsion
http://hdl.handle.net/10525/2730
Title: Special compositions in affinely connected spaces without a torsion<br/><br/>Authors: Zlatanov, Georgi<br/><br/>Abstract: Let AN be an affinely connected space without a torsion. With the help of N independent vector fields and their reciprocal covectors is built an affinor which defines a composition Xn ×Xm (n+m = N). The structure is integrable. New characteristics by the coefficients of the derivative equations are found for special compositions, studied in [1], [3]. Two-dimensional manifolds, named as bridges, which cut the both base manifolds of the composition are introduced. Conditions for the affine deformation tensor of two connections where the composition is simultaneously of the kind (g-g) are found.<br/><br/>Description: 2000 Mathematics Subject Classification: 53B05, 53B99.Sat, 01 Jan 2011 00:00:00 GMTOn realizability of p-groups as Galois groups
http://hdl.handle.net/10525/2729
Title: On realizability of p-groups as Galois groups<br/><br/>Authors: Michailov, Ivo M.; Ziapkov, Nikola P.<br/><br/>Abstract: In this article we survey and examine the realizability of p-groups as Galois groups over arbitrary fields. In particular we consider various cohomological criteria that lead to necessary and sufficient conditions for the realizability of such a group as a Galois group, the embedding problem (i.e., realizability over a given subextension), descriptions of such extensions, automatic realizations among p-groups, and related topics.<br/><br/>Description: 2000 Mathematics Subject Classification: 12F12, 15A66.Sat, 01 Jan 2011 00:00:00 GMT