bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sur la Non Compatibilité de l'Equivalence de Calkin Avec le Calcul Fonctionnel de Nagy-Foias
Authors: Esterle J. , Zarouf F. 
Published: December 2010

AbstractNous montrons qu'il existe deux contractions T1 et T2 de classe C0 telles que T1 — T2 soit compact et une fonction intérieure h telle que h(T1) — h(T2) soit non compact.
A Note on Relations Between the Zeta-Functions of Galois Coverings of Curves Over Finite Fields
Authors: Pacheco Amilcar 
Published: December 2010

AbstractLet C be a complete irreducible nonsingular algebraic curve defined over a finite field k. Let G be a finite subgroup of the group of automorphisms Aut(C) of C. We prove that certain idempotent relations in the rational group ring Q[G] imply other relations between the zeta-functions of the quotient curves C/H, where H is a subgroup of G. In particular we generalize some results of Kani in the special case of curves over finite fields.
On a Relationship Between Adjoint Orbits and Conjugacy Classes of a Lie Group
Authors: Wildberger N. J. 
Published: December 2010

AbstractLet G be a Lie group with adjoint orbits θi and corresponding conjugacy classes Ci = exp θi, i = 1, 2, 3. We show that if G is nilpotent or compact, there is a neighbourhood U of 0 in g such that if θi ∊ U then θ3 ⊂ θ1 + θ2 if and only if C3 ⊂ C1C2.
Hurwitz Groups and G2(q)
Authors: Malle Gunter 
Published: December 2010

AbstractFinite factor groups of are called Hurwitz groups. Here we prove that apart from 2G2(3), G2(2), G2(3) and G2(4), all the groups 2G2(32n+1) and G2(q), q = pn, p € P, are Hurwitz groups. For the proof, (2, 3, 7) structure constants are calculated from the character tables [2], [7], and then with the lists of maximal subgroups [8], [5], the existence of generating triples is deduced.
Vector Invariants of Symmetric Groups
Authors: Campbell H. E. A. , Hughes I. , Pollack R. D. 
Published: December 2010

AbstractLet M be a free module of rank n over a commutative ring R with unit and let Σn denote the symmetric group acting on a fixed basis of M in the usual way. Let Mm denote the direct sum of m copies of M and let S be the symmetric ring of Mm over R. Then each element of Σn acts diagonally on Mm and consequently on S; denote by Xn the subgroup of Gl(Mm) so defined. The ring of invariants, SΣn, is called the ring of vector invariants by H. Weyl [ 3, Chapter II, p. 27] when R = Q. In this paper a set of generators valid over any ring R is given. This set of generators is somewhat larger than Weyl's. It is interesting to note that, over the integers, his algebra and SΣn have the same Hilbert-Poincaré series, are equal after tensoring with the rationals, and have the same fraction fields, although they
are not equal.
Pseudo-Integrality
Authors: Anderson David F. , Houston Evan G. , Zafrullah Muhammad 
Published: December 2010

AbstractLet R be an integral domain. An element u of the quotient field of R is said to be pseudo-integral over R if uIv ⊆ Iv for some nonzero finitely generated ideal I of R. The set of all pseudo-integral elements forms an integrally closed (but not necessarily pseudo-integrally closed) overling R ofR. It is shown that , where X is a family of indeterminates; pseudo-integrality is analyzed in rings of the form D + M; and an example is given to show that pseudo-integrality does not behave well with respect to
localization.
On Superrecurrence
Authors: Dajani Karma 
Published: December 2010

AbstractLet T be a non-singular, conservative, ergodic automorphism of a Lebesgue space. We study a kind of weighted cocycles called H-cocycles. We introduce the notions of H-superrecurrence and H-supertransience. We use skew products to give necessary and sufficient conditions for H-superrecurrence.
Stable Rank and the -Equation
Authors: Rupp Rudolf 
Published: December 2010

AbstractLet G denote a plane domain bounded by finitely many closed, non-intersecting Jordan curves. We show the following refinement of the stable rank one property of : Suppose that for there exists δ > 0 such that . Then there exist such thatf + hg = exp (k).Also we obtain a partial result for the algebra H∞(G).
The Parity Distribution of Traces in Imaginary Quadratic Fields
Authors: Dummit D. S. 
Published: December 2010

AbstractComputations of the Iwasawa λ -invariant for imaginary quadratic fields showed a discrepancy in the proportion of even and odd traces of certain integers from these imaginary quadratic fields. This paper shows that such a discrepancy is in some sense to be expected and that the proportion of even and odd traces of principal generators of powers of prime ideals in imaginary quadratic fields is related to the 3-primary component of the class group.
On Density of Generalized Polynomials
Authors: Dyn N. , Lubinsky D. S. , Shekhtman Boris 
Published: December 2010

AbstractWe consider the density in C[a, b] of generalized polynomials of the form The main point of this note is that total positivity of K(x, t) has little relationship to density: There is a symmetric, analytic, totally positive (in fact ETP (∞)) kernel K for which these generalized polynomials are not dense.
Simplicity of Categories Defined by Symmetry Axioms
Authors: Lowen-Colebunders E. , Szabo Z. G. 
Published: December 2010

AbstractWe consider two generalizations R0w and R0 of the usual symmetry axiom for topological spaces to arbitrary closure spaces and convergence spaces. It is known that the two properties coincide on Top and define a non-simple subcategory. We show that R0W defines a simple subcategory of closure spaces and R0 a non-simple one. The last negative result follows from the stronger statement that every epireflective subcategory of R0 Conv containing all T1 regular topological spaces is not simple. Similar theorems are shown for the topological categories Fil and Mer.
A Question of Valdivia on Quasinormable Fréchet Spaces
Authors: Bonet José 
Published: December 2010

AbstractIt is proved that a Fréchet space is quasinormable if and only if every null sequence in the strong dual converges equicontinuously to the origin. This answers positively a question raised by Valdivia. As a consequence a positive answer to a problem of Jarchow on Fréchet Schwartz spaces is obtained.
Variations on Müntz's Theme
Authors: Borwein Peter B. 
Published: December 2010

AbstractWe consider some variations of Muntz's classical theorem on when Span{xλi} is dense in C[0,1]. We prove, for example, that if then the collection of spaces is dense in C[0,1] if and only if lim sup(log n)/λn = ∞. Another variation concerns the denseness of the union of spaces of the form The derivations of these results require an examination of the location of the zeros of the associated Chebyshev polynomials.
The Behaviour of Homology in the Localization of Finite Groups
Authors: Casacuberta Carles 
Published: December 2010

AbstractWe show that, for a finite group G and a prime p, the following facts are equivalent: (i) the p-localization homomorphism l: G —> Gp induces p-localization on integral homology; (ii) the higher homotopy groups of the Bousfield-Kan Zp-completion of a K(G, 1) vanish; (iii) the group G is p-nilpotent.
Simultaneous Monotone Lp Approximation, p → ∞
Authors: Huotari Robert , Sahab Salem 
Published: December 2010

AbstractSuppose that f, g € L∞ [0,1 ] have discontinuities of the first kind only. Using the measure, max{ ∥f — h∥p, ∥g — h∥p}, of simultaneous Lp approximation, we show that the best simultaneous approximations f and g by nondecreasing functions converge uniformly as p → ∞. Part of the proof involves a discussion of discrete simultaneous approximation in a general context. Assuming only that f and g are approximately continuous, we show that their simultaneous best monotone Lp approximation is continuous.
JV-Algèbres et JH*-Algèbres
Authors: Bensebah Ali 
Published: December 2010

RésuméIn the present article we generalize Theorem 2.3 of [6] in the case of JV algebras without a unit element and we obtain as a consequence that the multiplicativity of the involution ((xy)* = y*x*) in the definition of a JH*-algebra is redundant (see [3]). We end this paper with a theorem on unital JH*-algebra which is a nonassociative extension of the main result in [4].
On Product Partitions of Integers
Authors: Harris V. C. , Subbarao M. V. 
Published: December 2010

AbstractLet p*(n) denote the number of product partitions, that is, the number of ways of expressing a natural number n > 1 as the product of positive integers ≥ 2, the order of the factors in the product being irrelevant, with p*(1) = 1. For any integer if d is an ith power, and = 1, otherwise, and let . Using a suitable generating function for p*(n) we prove that
Convolutions with Unbounded Unity
Authors: Sitaramaiah V. , Subbarao M. V. 
Published: December 2010

AbstractOn the set F of complex-valued arithmetic functions we construct an infinite family of convolutions, that is, binary operations ψ of the formso that (F, +, ψ) is a commutative ring, for which the unity is unbounded. Here + denotes pointwise addition.
Sur un Problème Périodique
Authors: Guennoun Zine E. A. 
Published: December 2010

RésuméDans cet article, nous considérons le problème d'existence d'une solution périodique du problème de la forme: y″ = f(t,y,y′), 0 ≦ t ≦ 1 où f: [0,1 ] X R x R —> R est une fonction continue qui n'est pas nécessairement périodique et sans condition de croissance sur la variable y′. Nous obtenons certaines extensions d'un théorème du type Nirenberg ainsi que de l'équation de Liénard.
Norm One Multipliers on Subspaces of Lp
Authors: Hare Kathryn E. 
Published: December 2010

AbstractWe present a new elementary proof of the fact that a norm one multiplier ϕ on LP(T) satisfying ϕ(0) = ϕ(k) = 1 is k-periodic, and extend this result, when possible, to multipliers on translation invariant subspaces of LP. A consequence of our work is that all such multipliers on HP(T) are the restriction of a norm one multiplier on LP(T).
On the Stability of Equivariant Bifurcation Problems and Their Unfoldings
Authors: Lari-Lavassani Ali , Lu Yung-Chen 
Published: December 2010

AbstractIn their book Singularities and Groups in Bifurcation Theory M. Golubitsky, I. Stewart and D. Schaeffer have introduced an equivariant version of Martinet's notion of V (for variety)-equivalence with parameter. In this paper we give a unified proof that, in this context, infinitesimal stability is equivalent to stability at the local level of germs and that stability in the unfolding category is equivalent to versality.
Symmetrically Completely Bounded Linear Maps Between C*-Algebras
Authors: Tang Wai-Shing 
Published: December 2010

AbstractWe study the properties of a new class SCB(L, B) of bounded linear maps, called symmetrically completely bounded maps, from a linear subspace L of a C* -algebra to another C*-algebra B. This class contains the class of all completely bounded linear maps from L to B. In particular, we obtain a representation theorem for maps in SCB(L, B) when B is the algebra of all bounded linear operators on a Hilbert space.
Higher Dimensional Harmonic Volume Can be Computed as an Iterated Integral
Authors: Faucette William M. 
Published: December 2010

AbstractIn this paper it is shown that the computation of higher dimensional harmonic volume, defined in [1], can be reduced to Harris' computation in the onedimensional case (See [3]), so that higher dimensional harmonic volume may be computed essentially as an iterated integral. We then use this formula to produce a specific smooth curve , namely a specific double cover of the Fermat quartic, so that the image of the second symmetric product of in its Jacobian via the Abel-Jacobi map is algebraically inequivalent to the image of under the group involution on the Jacobian.
A Method of Solving a Class of CIV Boundary Value Problems
Authors: Iraniparast Nezam 
Published: December 2010

AbstractA method will be introduced to solve problems utt — uss = h(s, t), u(t,t) - u(1+t,1 - t), u(s,0) = g(s), u(1,1) = 0 and for (s, t) in the characteristic triangle R = {(s,t) : t ≤ s ≤ 2 — t, 0 ≤ t ≤ 1}. Here represent the directional derivatives of u in the characteristic directions e1 = (— 1, — 1) and e2 = (1, — 1), respectively. The method produces the symmetric Green's function of Kreith [1] in both cases.
Topological Completeness of Function Spaces Arising in the Hausdorff Approximation of Functions
Authors: Beer Gerald 
Published: December 2010

AbstractLet X be a complete metric space. Viewing continuous real functions on X as closed subsets of X × R, equipped with Hausdorff distance, we show that C(X, R) is completely metrizable provided X is complete and sigma compact. Following the Bulgarian school of constructive approximation theory, a bounded discontinuous function may be identified with its completed graph, the set of points between the upper and lower envelopes of the function. We show that the space of completed graphs, too, is completely metrizable, provided X is locally connected as well as sigma compact and complete. In the process, when X is a Polish space, we provide a simple answer to the following foundational question: which subsets of X × R arise as completed graphs?
Non-Archimedean t-Frames and FM-Spaces
Authors: De Grande-De Kimpe N. , Perez-Garcia C. , Schikhof W. H. 
Published: December 2010

AbstractWe generalize the notion of t-orthogonality in p-adic Banach spaces by introducing t-frames (§2). This we use to prove that a Fréchet-Montel (FM-)space is of countable type (Theorem 3.1), the non-archimedeancounterpart of a well known theorem in functional analysis over ℝ or ℂ ([6], p. 231). We obtain several characterizations of FM-spaces (Theorem 3.3) and characterize the nuclear spaces among them (§4).
Compact Sets in CP(X) and Calibers
Authors: Kalamidas N. D. , Spiliopoulos G. D. 
Published: December 2010

AbstractThis presentation concerns the relation of chain conditions on a space X, with the weights of compact sets in Cp(X), generalizing up to the class of dσ-bounded spaces, or stable spaces. In the last case, stronger results are obtained for Corson compact subsets of CP(X).
Generalized Second Fundamental form for Lipschitzian Hypersurfaces by Way of Second Epi Derivatives
Authors: Noll Dominikus 
Published: December 2010

AbstractUsing second epi derivatives, we introduce a generalized second fundamental form for Lipschitzian hypersurfaces. In the case of a convex hypersurface, our approach leads back to the classical second fundamental form, which is usually obtained from the second fundamental forms of the outer parallel surfaces by means of a limit procedure.
An Easy Proof for Some Classical Theorems in Plane Geometry
Authors: Thas C. 
Published: December 2010

AbstractThe main result of this paper is a theorem about three conies in the complex or the real complexified projective plane. Is this theorem new? We have never seen it anywhere before. But since the golden age of projective geometry so much has been published about conies that it is unlikely that no one noticed this result. On the other hand, why does it not appear in the literature? Anyway, it seems interesting to "repeat" this property, because several theorems in connection with straight lines and (or) conies in projective, affine or euclidean planes are in fact special cases of this theorem. We give a few classical examples: the theorems of Pappus-Pascal, Desargues, Pascal (or its converse), the Brocard points, the point of Miquel. Finally, we have never seen in the literature a proof of these theorems using the same short method see the proof of the main theorem).
Some Characterizations of Dedekind α-Completeness of a Riesz Space
Authors: Abramovich Y. A. , Wickstead A. W. 
Published: December 2010

AbstractA vector lattice F is said to be Dedekind α-complete, where α is a cardinal number, provided that each non-empty order bounded subset D of F satisfying card(D) ≤ α has a supremum. Several characterizations of this property are presented here.
On Logarithmic Derivatives of Functions in a Class of Starlike Mappings
Authors: Gluchoff Alan D. 
Published: December 2010

AbstractThe purpose of this paper is to prove some facts about integral means of (d2/dz2)(log[f(z)/z])—or equivalently f″/f, for f in a class of starlike mappings of a "singular" nature. In particular it is noted that the Koebe function is not extremal for the Hardy means Mp(r,f″/f) for functions in this class.
M-Ideals and Function Algebras
Authors: Seddighi K. , Zahedani H. 
Published: December 2010

AbstractLet C(X) be the space of all continuous complex-valued functions defined on the compact Hausdorff space X. We characterize the M-ideals in a uniform algebra A of C(X) in terms of singular measures. For a Banach function algebra B of C(X) we determine the connection between strong hulls for B and its peak sets. We also show that M(X) the space of complex regular Borel measures on X has no M-ideal.
A Local Hopf Bifurcation Theorem for a Certain Class of Implicit Differential Equations
Authors: Kaczynski Tomasz , Krawcewicz Wieslaw 
Published: December 2010

AbstractThe local Hopf Bifurcation theorem is extended to implicit differential equations in Rn, of the form ẋ = f(x,ẋ, α), which are not solvable for the variable ẋ. The proof uses the S1 -degree of convex-valued mappings. An example of an implicit differential equation in R3 to which the presented theorem applies is provided.
Some Asymptotic Properties of Solutions of a Neutral Delay Equation With an Oscillatory Coefficient
Authors: Graef John R. , Spikes Paul W. 
Published: December 2010

AbstractThe authors consider the nonlinear neutral delay differential equationand obtain results on the asymptotic behavior of solutions. Some of the results require that P(t) has arbitrarily large zeros or that P(t) oscillates about — 1
One-Dimensional Monoid Rings with n-Generated Ideals
Authors: Okon James S. , Paul Vicknair J. 
Published: December 2010

AbstractA commutative ring R is said to have the n-generator property if each ideal of R can be generated by n elements. Rings with the n-generator property have Krull dimension at most one. In this paper we consider the problem of determining when a one-dimensional monoid ring R[S] has the n-generator property where R is an artinian ring and S is a commutative cancellative monoid. As an application, we explicitly determine when such monoid rings have the three-generator property.
On the Minimal Convex Shell of a Convex Body
Authors: Peri Carla 
Published: December 2010

AbstractFor any convex body C in ℝd we introduce the notion of the convex shell and we prove that there exists a unique "minimal" convex shell, extending the notion of the minimal spherical shell of C. Then we prove that a "typical" convex body touches the boundary of its minimal convex shell in precisely d + 2 points.
Self-Affine Processes and the Ergodic Theorem
Authors: Vervaat Wim 
Published: December 2010

AbstractKnown results for strictly stable motions as finiteness of moments and local boundednessof sample-path variation are generalized to self-affine processes, i.e., self-similar processes with stationary increments. The proofs are new, even for stable motions, and are obtained by applying the ergodic theorem to powers of the (one-sided) increments.
Geometric Proofs of some Classical Results on Boundary Values for Analytic Functions
Authors: Villamor Enrique 
Published: December 2010

AbstractIn this note we are going to give a geometric proof, using the method of the extremal metric, of the following result of Beurling. For any analytic function f(z) in the unit disc Δ of the plane with a bounded Dirichlet integral, the set E on the boundary of the unit disc where the nontangential limits of f(z) do not exist has logarithmic capacity zero. Also, using an unpublished result of Beurling, we will prove different results on boundary values for different classes of functions.
On Closed Subsets of Root Systems
Authors: Doković D. Ž. , Check P. , Hée J.-Y. 
Published: December 2010

AbstractLet R be a root system (in the sense of Bourbaki) in a finite dimensional real inner product space V. A subset P ⊂ R is closed if α, β ∊ P and α + β ∊ R imply that α + β ∊ P. In this paper we shall classify, up to conjugacy by the Weyl group W of R, all closed sets P ⊂ R such that R\P is also closed. We also show that if θ:R —> R′ is a bijection between two root systems such that both θ and θ-1 preserve closed sets, and if R has at most one irreducible component of type A1, then θ is an isomorphism of root systems.
On an Upper Bound for the Heat Kernel on SU*(2n)/ Sp(n)
Authors: Sawyer P. 
Published: December 2010

AbstractJean-Philippe Anker made an interesting conjecture in [2] about the growth of the heat kernel on symmetric spaces of noncompact type. For any symmetric space of noncompact type, we can writewhere ϕ0 is the Legendre function and q, "the dimension at infinity", is chosen such that limt—>∞Vt(x) = 1 for all x. Anker's conjecture can be stated as follows: there exists a constant C > 0 such thatwhere is the set of positive indivisible roots. The behaviour of the function ϕ0 is well known (see [1]).The main goal of this paper is to establish the conjecture for the spaces SU*(2n)/ Sp(n).
Overrings of Half-Factorial Domains
Authors: Anderson David F. , Chapman Scott T. , Smith William W. 
Published: December 2010

AbstractAn atomic integral domain D is a half-factorial domain (HFD) if for any irreducible elements α1,..., αn, β1,..., βm of D with α1... αn = β1 ...βm, then n = m. In [3], Anderson, Anderson, and Zafrullah explore factorization problems in overrings of HFDs and ask whether a localization of a HFD is again a HFD. We construct an example of a Dedekind domain which is a HFD, but with a localization which is not a HFD. We also give an example of a Dedekind domain where each localization is a HFD, but with an overring which is not a HFD.
Trace, Symmetry and Orthogonality
Authors: Craigen R. 
Published: December 2010

AbstractDoes there exist a circulant conference matrix of order > 2? When is there a symmetric Hadamard matrix with constant diagonal? How many pairwise disjoint, amicable weighing matrices of order n can there be? These are questions concerning which the trace function gives a great deal of insight. We offer easy proofs of the known solutions to the first two, the first being new, and develop new results regarding the latter question. It is shown that there are 2t disjoint amicable weighing matrices of order 2tp, where p is odd, and that this is an upper bound for t ≤ 1. An even stronger bound is obtained for certain cases.
Presentations of the Free Metabelian Group of Rank 2
Authors: Evans Martin J. 
Published: December 2010

AbstractLet F3 denote the free group of rank 3 and M2 denote the free metabelian group of rank 2. We say that x * F3 is a primitive element of F3 if it can be included a in some basis of F3. We establish the existence of presentations such that N does not contain any primitive elements of F3.
Lip α Approximation on Closed Sets with Lip α Extension
Authors: Bonilla A. , Fariña J. C. 
Published: December 2010

AbstractLet F be a relatively closed subset of a domain G in the complex plane. Let f be a function that is the limit, in the Lip α norm on F, of functions which are holomorphic or meromorphic on G (0 < α < 1). We prove that, under the same conditions that give Lip α-approximation (0 < α < 1 ) on relatively closed subsets of G, it is possible to choose the approximating function m in such a way that f — m can be extended to a function belonging to lip
A Remark on a Weighted Landau Inequality of Kwong and Zettl
Authors: Brown R. C. , Hinton D. B. , Kwong M. K. 
Published: December 2010

AbstractIn this note we extend a theorem of Kwong and Zettl concerning the inequalityThe Kwong-Zettl result holds for 1 ≤ p < ∞ and real numbers α, β, γ such that the conditions (i) β = (α + γ)/2, (ii) β > - 1 , and (iii) γ - 1 - p hold. Here the inequality is proved with β satisfying (i) for all α, γ except p — 1,-1 — p. In this case the inequality is false; however u is shown to satisfy the inequality