bluuebunny/crossref_metadata_2025 huggingface dataset:
A Plessner Decomposition Along Transverse Curves
Authors: Beatrous Frank , Li Songying
Published: December 2010

A classical theorem of Plessner [6] asserts that any holomorphic function f on the unit disk partitions the unit circle, modulo a null set, into two disjoint pieces such that at each point of the first piece, f has a non-tangential limit, and at each point of the second piece, the cluster set of f in any Stolz angle is the entire plane. Higher dimensional versions of this result were first obtained by Calderon [2], who considered holomorphic functions on Cartesian products of half-planes. In this setting, an exact analogue of the one-dimensional result is obtained, in which the circle is replaced by the distinguished boundary, and the Stolz angles are replaced by products of cones in the coordinate half-planes. The ideas of Calderon were further developed by Rudin [8, pp. 79-83], who considered holomorphic and invariant harmonic functions in the ball of Cn. In this case, the circle is replaced by the unit sphere, and the Stolz angles are replaced by the approach regions of Korányi [4].
Spherical Homology Classes in the Bordism of Lie Groups
Authors: Kane Richard , Moreno Guillermo
Published: December 2010

The mod torsion Hurewicz map

for compact Lie groups provides a useful and efficient means of studying G. In effect, it measures how far G fails to be a product of spheres. For the Hopf-Samelson theorem (see [17]) tells us that

In other words

Serre pointed out that there exists a map

inducing this Q isomorphism.
Uniform Harmonic Approximation with Continuous Extension to the Boundary
Authors: Goldstein M. , Ow W. H.
Published: December 2010

Let G be a domain in the complex plane and F a nonempty subset of G such that F is the closure in G of its interior F0. We will say f ∊ C1(F) if f is continuous on F and possesses continuous first partial derivatives in F which extend continuously to F as finite-valued functions. Let G* – F be connected and locally connected, f ∊ C1(F) be harmonic in F0, and E be a subset of ∂F ∩ ∂G (here G* denotes the one-point compactification of G and the boundaries ∂F, ∂G are taken in the extended plane). Suppose there is a sequence 〈hn〉 of functions harmonic in G such that

uniformly on F as n → ∞.
On the Essential Spectra of Quasisimilar Operators
Authors: Herrero Domingo A.
Published: December 2010

B. Sz.-Nagy and C. Foiaş gave the first examples of quasisimilar operators with different spectra [25]. Indeed, quasisimilar operators can even have different spectral radius [19] (see also [15]). Nevertheless, T. B. Hoover has shown in [19] that if T and S are quasisimilar, then σ(T)∩σ(S) ≠ ∅, where σ(R) denotes the spectrum of the (bounded linear) operator R. In [12], the author improved Hoover's result by showing that each component of σ(S) intersects σ(T), and viceversa. This, in turn, was further improved by L. A. Fialkow in [7]. (Actually, Fialkow's results were obtained independently of [12].)

L. A. Fialkow [7] and L. R. Williams [27] independently proved that σe(T)∩σe(S) ≠ ∅, where σe(R) denotes the essential spectrum of R. Several authors have raised the following natural question:

Is it also true that each component of σe(S) intersects σe(T), and viceversa? [7] [21] [26].
Homomorphisms Between Algebras of Continuous Functions
Authors: Llavona J. G. , Jaramillo J. A.
Published: December 2010

We are concerned in this paper with the study of homomorphisms between different algebras of continuous functions, especially the algebras of real functions which are either weakly continuous on bounded sets or weakly uniformly continuous on bounded sets on a Banach space (see definitions below).

These spaces of weakly [uniformly] continuous functions appeared in relation with some questions in Infinite-dimensional Approximation Theory (see [4], [6], [11], [12], [13] and [16]); and since the structure of these function spaces is closely related with properties of different weak topologies (the bounded-weak and bounded-weak* topologies, respectively) and with the structure of Banach spaces on which they are defined, their study also presents interest from the point of view of Banach space theory, as can be seen in [2], [12] or [17].
Homogeneous Complex Manifolds with more than One End
Authors: Gilligan B. , Oeljeklaus K. , Richthofer W.
Published: December 2010

For homogeneous spaces of a (real) Lie group one of the fundamental results concerning ends (in the sense of Freudenthal [8] ) is due to A. Borel [6]. He showed that if X = G/H is the homogeneous space of a connected Lie group G by a closed connected subgroup H, then X has at most two ends. And if X does have two ends, then it is diffeomorphic to the product of R with the orbit of a maximal compact subgroup of G.

In the setting of homogeneous complex manifolds the basic idea should be to find conditions which imply that the space has at most two ends and then, when the space has exactly two ends, to display the ends via bundles involving C* and compact homogeneous complex manifolds. An analytic condition which ensures that a homogeneous complex manifold X has at most two ends is that X have non-constant holomorphic functions and the structure of such a space with exactly two ends is determined, namely, it fibers over an affine homogeneous cone with its vertex removed with the fiber being compact [9], [13].
Plane Curves With Nodes
Authors: Treger Robert
Published: December 2010

A smooth algebraic curve is birationally equivalent to a nodal plane curve. One of the main problems in the theory of plane curves is to describe the situation of nodes of an irreducible nodal plane curve (see [16, Art. 45], [10], [7, Book IV, Chapter I, §5], [12, p. 584], and [3]).

Let n denote the degree of a nodal curve and d the number of nodes. The case (AZ, d) — (6,9) has been analyzed by Halphen [10]. It follows from Lemma 3.5 and Proposition 3.6 that this is an exceptional case. The case d ≦n(n + 3)/6, d ≦(n — 1)(n — 2)/2, and (n, d) ≠ (6,9) was investigated by Arbarello and Cornalba [3]. We present a simpler proof (Corollary 3.8).

We consider the main case which is particularly important due to its applications to the moduli variety of curves, compare [19, Chapter VIII, Section 4]. Let Vn,d be the variety of irreducible curves of degree n with d nodes and no other singularities such that each curve of Vn,d can be degenerated into n lines in general position (see [17]).
A Mixed Parseval's Equation And a Generalized Hankel Transformation of Distributions
Authors: Betancor J. J.
Published: December 2010

Let an integral transform T﹛f﹜ of a complex valued function f(x) defined over the interval (0, ∞) be defined as One of the most usual procedures to extend the classical transform (l.a) to generalized functions consists in constructing a space A of testing functions over (0, ∞) which is closed with respect to the classical transform (l.a) and then the corresponding transform of the generalized function/ of the dual space of A is defined through

This approach has been followed by L. Schwartz [13] and A. H. Zemanian [20], amongst others.
Reflexive Bimodules
Authors: Fuller K. R. , Nicholson W. K. , Watters J. F.
Published: December 2010

If VK is a finite dimensional vector space over a field K and L is a lattice of subspaces of V, then, following Halmos [11], alg L is defined to be (the K-algebra of) all K-endomorphisms of V which leave every subspace in L invariant. If R ⊆ end(VK) is any subalgebra we define lat R to be (the sublattice of) all subspaces of VK which are invariant under every transformation in R. Then R ⊆ alg [lat R] and R is called a reflexive algebra when this is equality. Every finite dimensional algebra is isomorphic to a reflexive one ([4]) and these reflexive algebras have been studied by Azoff [1], Barker and Conklin [3] and Habibi and Gustafson [9] among others.
On the Semi-Tensor Product of the Dyer-Lashof and Steenrod Algebras
Authors: Campbell H. E. A. , Selick P. S.
Published: December 2010

This paper arises out of joint work with F. R. Cohen and F. P. Peterson [5, 2, 3] on the joint structure of infinite loop spaces QX. The homology of such a space is operated on by both the Dyer-Lashof algebra, R, and the opposite of the Steenrod algebra A∗. We describe a convenient summary of these actions; let M be the algebra which is R ⊗ A∗ as a vector space and where multiplication Q1 ⊗ PJ. Q1’ ⊗ PJ’∗ is given by applying the Nishida relations in the middle and then the appropriate Adem relations on the ends. Then M is a Hopf algebra which acts on the homology of infinite loop spaces.
Composition with a Nonhomogeneous Bounded Holomorphic Function on the Ball
Authors: Choa Jun Soo , Kim Hong Oh
Published: December 2010

For an integer n > 1, the letters U and Bn denote the open unit disc in C and the open euclidean unit ball in Cn, respectively. It is known that the homogeneous polynomials

where bα is chosen so that , have the following pull-back property:

If g ∈ ℬ(U) the Block space, then , the space of holomorphic functions on Bn of bounded mean oscillation, forand.
On the Word Problem for Orthocomplemented Modular Lattices
Authors: Roddy Michael S.
Published: December 2010

In [16] Freese showed that the word problem for the free modular lattice on 5 generators is unsolvable. His proof makes essential use of Mclntyre's construction of a finitely presented field with unsolvable word problem [30]. (We follow Cohn [7] in calling what is commonly called a division ring a field, and what is commonly called a field a commutative field.) In this paper we will use similar ideas to obtain unsolvability results for varieties of modular ortholattices. The material in this paper is fairly wide ranging, the following are recommended as reference texts.
Sur le Socle Dans Les Algèbres de Jordan-Banach
Authors: Aupetit Bernard , Baribeau Line
Published: December 2010

Dans une algèbre de Banach, le socle joue le même rôle que l'ensemble des opérateurs de rang fini dans le cas de l'algèbre des opérateurs linéaires continus sur un espace de Banach. Aussi est-il intéressant de savoir dans quels cas le socle n'est pas réduit à zéro.

En 1968, B. A. Barnes ([6], Théorème 2.1 et Théorème 2.2) a pu démontrer le théorème suivant:

Théorème 1. Soit A une algèbre de Banach complexe sans radical. Supposonsque le spectre de chaque élément de A est dénombrable. Alors le socle de A estnon nul.
Generalized Newton-Puiseux Theory and Hensel's Lemma in C[[x, y]]
Authors: Kuo Tzee-Char
Published: December 2010

The Newton polygon and the Newton-Puiseux algorithm ([3], p. 370, [8], p. 98), and their generalizations, serve as a powerful tool for analysing the singularities of a given function. Yet experts know how difficult it is to keep track of them when one, or several, blowing-ups are applied. Thus many interesting theorems are stated under the strong, rather undesirable, assumption that the Newton faces are non-degenerate.

In this paper, we introduce a method which is parallel to the classical Newton-Puiseux theory, yet avoids blowing-ups and fractional power series, except in the proofs.
Diameters in Typical Convex Bodies
Authors: Bárány Imre , Zamfirescu Tudor
Published: December 2010

The most usual diameters in the world are those of a sphere and they all contain its centre. More generally, a chord of a convex body in Rd is called a diameter if there are two parallel supporting hyperplanes at the two endpoints of the chord.

It is easily seen that there are points on at least two diameters. From a result of Kosiński [6] proved in a more general setting it follows that every convex body has a point lying on at least three diameters. Does a typical convex body behave like a sphere and contain a point on infinitely or even uncountably many diameters?

But what is a typical convex body? The space 𝒦 of all convex bodies (d-dimensional compact convex sets) in Rd, equipped with the Hausdorff metric, is a Baire space.
Resolubilite Local Pour des Equations Semi Lineaires Complexes
Authors: Dehman B.
Published: December 2010

Dans ce travail, nous construisons des solutions pour une certaine classe d'équations semi-linéaires complexes dans le plan. Plus précisément on considère prés d'un point XQde R2 l'équation

où Pest un opérateur différentiel d'ordre m(m≧ 1) à coefficients C∞ complexes, et o ù ƒest à valeurs complexes, analytique en et seulement C∞ en x.En supposant alors que Pest de type principal près de xoet vérifie la condition de Nirenberg-Trêves sous elliptique (que nous noterons ((P), voir [5]), nous construisons une solution locale de (*), de classe C∞ (Théorème 2.1).

Ce résultat échappe évidemment aux théorèmes classiques d'existence de Hamilton-Jacobi et de Cauchy-Kowalevsky.
Codimension 2 Symmetric Homoclinic Bifurcations and Application to 1:2 Resonance
Authors: Li Chengzhi , Rousseau Christiane
Published: December 2010

In this paper we study a codimension 3 form of the 1:2 resonance. It was first noted by Arnold [3] that the study of bifurcations of symmetric vector fields under a rotation of order q yields information about Hopf bifurcation for a fixed point of a planar diffeomorphism F with eigenvalues . The map Fq can be identified to arbitrarily high order with the flow map of a symmetric vector field having a double-zero eigenvalue ([3], [4], [10], [23]). The resonance of order 2 (also called 1:2 resonance) considered here is the case of a pair of eigenvalues —1 with a Jordan block of order 2. The diffeomorphism then has normal form around the origin given by [4]:
Constructions of Brauer-Severi Varieties and Norm Hypersurfaces
Authors: Kang Ming-Chang
Published: December 2010

Let k be any field, A a central simple k-algebra of degree m (i.e., dimk A = m2). Several methods of constructing the generic splitting fields for A are proposed and Saltman proves that these methods result in almost the same generic splitting field [8, Theorems 4.2 and 4.4]. In fact, the generic splitting field constructed by Roquette [7] is the function field of the Brauer- Severi variety Vm(A) while the generic splitting field constructed by Heuser and Saltman [4 and 8] is the function field of the norm surface W(A). In this paper, to avoid possible confusion about the dimension, we shall call it the norm hypersurface instead of the norm surface.
On Automorphisms of Complete Algebras And The Isomorphism Problem for Modular Group Rings
Authors: Röhl Frank
Published: December 2010

In [5], Roggenkamp and Scott gave an affirmative answer to the isomorphism problem for integral group rings of finite p-groups G and H, i.e. to the question whether ZG ⥲ ZH implies G ⥲ H (in this case, G is said to be characterized by its integral group ring). Progress on the analogous question with Z replaced by the field Fp of p elements has been very little during the last couple of years; and the most far reaching result in this area in a certain sense - due to Passi and Sehgal, see [8] - may be compared to the integral case, where the group G is of nilpotency class 2.
Universal Varieties Of (0, 1)-Lattices
Authors: Goralčík P. , Koubek V. , Sichler J.
Published: December 2010

This article fully characterizes categorically universal varieties of (0, 1)-lattices (that is, lattices with a least element 0 and a greatest element 1 regarded as nullary operations), thereby concluding a series of partial results [3, 5, 8, 10, also 14] which originated with the proof of categorical universality for the variety of all (0, 1)-lattices by Grätzer and Sichler [6].

A category C of algebras of a given type is universal if every category of algebras (and equivalently, according to Hedrlín and Pultr [7 or 14], also the category of all graphs) is isomorphic to a full subcategory of C. The universality of C is thus equivalent to the existence of a full embedding Φ : G→C of the category G of all graphs and their compatible mappings into C. When Φ assigns a finite algebra to every finite graph, we say that C is finite-to-finite universal.
Heights and L-Series
Authors: Hatcher Rhonda Lee
Published: December 2010

Let be a cusp form of weight 2k and trivial character for Γ0(N), where N is prime, which is orthogonal with respect to the Petersson product to all forms g(dz), where g is of level L < N, dL\N. Let K be an imaginary quadratic field of discriminant — D where the prime N is inert. Denote by ∊ the quadratic character of determined by ∊(p) = (—D/p) for primes p not dividing D. For A an ideal class in K, let rA(m) be the number of integral ideals of norm m in A. We will be interested in the Dirichlet series L(f,A,s) defined by
Extremal Problems for the Classes SR-p and TR-p
Authors: Hengartner Walter , Szapiel Wojciech
Published: December 2010

Let H(D) be the linear space of analytic functions on a domain D of ℂ endowed with the topology of locally uniform convergence and let H‘(D) be the topological dual space of H(D). For domains D which are symmetric with respect to the real axis we use the notation Furthermore, denote by S the set of all univalent mappings f defined on the unit disk Δ which are normalized by f (0) = 0 and f‘(0) =1.
Functional Equations, Distributions and Approximate Identities
Authors: Baker John A.
Published: December 2010

The subject of this paper is the use of the theory of Schwartz distributions and approximate identities in studying the functional equation

The aj’s and b are complex-valued functions defined on a neighbourhood, U, of 0 in Rm, hj. U → Rn with hj(0) = 0 and fj, g: Rn → C for 1 ≦ j ≦ N. In most of what follows the aj's and hj's are assumed smooth and may be thought of as given. The fj‘s, b and g may be thought of as the unknowns. Typically we are concerned with locally integrable functions f1, … , fN such that, for each s in U, (1) holds for a.e. (almost every) x ∈ Rn, in the sense of Lebesgue measure.
Simply Connected Limits
Authors: Paré Robert
Published: December 2010

The importance of finite limits in completeness conditions has been long recognized. One has only to consider elementary toposes, pretoposes, exact categories, etc., to realize their ubiquity. However, often pullbacks suffice and in a sense are more natural. For example it is pullbacks that are the essential ingredient in composition of spans, partial morphisms and relations. In fact the original definition of elementary topos was based on the notion of partial morphism classifier which involved only pullbacks (see [6]). Many constructions in topos theory, involving left exact functors, such as coalgebras on a cotriple and the gluing construction, also work for pullback preserving functors. And pullback preserving functors occur naturally in the subject, e.g. constant functors and the Σα. These observations led Rosebrugh and Wood to introduce partial geometric morphisms; functors with a pullback preserving left adjoint [9]. Other reasons led Kennison independently to introduce the same concept under the name semi-geometric functors [5].
Explicit Classifications of Some 2-Extensions of a Field of Characteristic Different from 2
Authors: Kiming Ian
Published: December 2010

Let p be a prime number. Let k be a field of characteristic different from p and containing the p-th roots of unity. Let be a finite group. Let L/k be a finite normal extension with Galois group and let c be a 2-cocycle on with coefficients in , where acts trivially on By Emb(L/k, c) we denote the question of the existence of a finite normal extension M of k, such that M contains L, such that [M: L] = p, and such that, denoting by the Galois group of M/k, the extension is given by the class of c.
On the Points of Inflection of Bessel Functions of Positive Order, I
Authors: Lorch Lee , Szego Peter
Published: December 2010

The primary concern addressed here is the variation with respect to the order v > 0 of the zeros jʺvk of fixed rank of the second derivative of the Bessel function Jv(x) of the first kind. It is shown that jʺv1 increases 0 < v < ∞ (Theorem 4.1) and that jʺvk increases in 0 < v ≤ 3838 for fixed k = 2, 3,… (Theorem 10.1).
Representation Formulas for Integrable and Entire Functions of Exponential Type II
Authors: Frappier Clément
Published: December 2010

We adopt the terminology and notations of [5]. If f ∈ Bτ is an entire function of exponential type τ bounded on the real axis then we have the complementary interpolation formulas [1, p. 142-143]

and

where t, γ are reals and
Berg's Technique for Pseudo-Actions With Applications to af Embeddings
Authors: Loring Terry A.
Published: December 2010

Berg's interchange technique is generalized to the context of certain new objects called pseudo-actions. This is used to find a more geometric proof of the Pimsner-Voiculescu theorem on the AF embedding of the irrational rotation algebras. Connections with Berg's original results are briefly examined.

Embedding diagrams are introduced to provide a uniform way of describing embeddings of transformation group C*-algebras C(X) ⋊ ℤ into AF algebras. Pimsner has classified the transformation group C* -algebras which can be AF embedded. We present a new proof of this result using embedding diagrams and pseudo-actions. The need to calculate the join of an open cover with its iterates under the transformation has been eliminated.
Parametrizing Fuchsian Subgroups of the Bianchi Groups
Authors: Maclachlan C. , Reid A. W.
Published: December 2010

Let dbe a positive square-free integer and let Od denote the ring of integers in . The groups PSL2(Od) are collectively known as the Bianchi groups and have been widely studied from the viewpoints of group theory, number theory and low-dimensional topology. The interest of the present article is in geometric Fuchsian subgroups of the groups PSL2(Od). Clearly PSL2 is such a subgroup; however results of [18], [19] show that the Bianchi groups are rich in Fuchsian subgroups.
Multidimensional Iterative Interpolation
Authors: Deslauriers Gilles , Dubois Jacques , Dubuc Serge
Published: December 2010

We define an iterative interpolation process for data spread over a closed discrete subgroup of the Euclidean space. We describe the main algebraic properties of this process. This interpolation process, under very weak assumptions, is always convergent in the sense of Schwartz distributions. We find also a convenient necessary and sufficient condition for continuity of each interpolation function of a given iterative interpolation process.
The Hölder Exponent for Radially Symmetric Solutions of Porous Medium Type Equations
Authors: Hernandez Gaston E. , Roussos Ioannis M.
Published: December 2010

The density u(x, t) of an ideal gas flowing through a homogeneous porous media satisfies the equation Here m > 1 is a physical constant and u also satisfies the initial condition If the initial data is not strictly positive it is necessary to work with generalized solutions of the Cauchy problem (1), (2) (see [1]). By a weak solution we shall mean a function u(x, t) such that for (in the sense of distributions) and
On the Classification of Manifolds Up to Finite Ambiguity
Authors: Kreck Matthias , Triantafillou Georgia
Published: December 2010

In the early 70's Dennis Sullivan applied his theory of minimal models and surgery to the classification of 1-connected closed smooth manifolds of dimension ≥ 5 up to finite ambiguity [Su]. To a diffeomorphism class of such a manifold M he assigns the isomorphism class given by the real minimal model ℳ (M), the integral structure in form of various lattices and the real Pontryagin classes. If one controls the torsion of the manifolds by some bound, his result is that the map given by the triple above is finite-to-one ([Su], Theorem 13.1). He also proves a realization result for the rational minimal model and the Pontryagin classes but not for the lattices ([Su], Theorem 13.2).
Scattering Theory And Spectral Representations For General Wave Equations With Short Range Perturbations
Authors: Yamamoto Kazuhiro
Published: December 2010

In this paper we shall develop the scattering theory introduced by Lax and Phillips [5] for the following general wave equation; where Ω is an exterior domain Rn(n ≥ 3) with the smooth boundary δΩ and B is either a Dirichlet boundary condition or of the form Bu = Vi(x)aij(x)δju+σ(x)u with the unit outer normal vector v(x) = (v1 , … , vn) at x ∈ δ Ω. The precise assumptions on α(x), aij(x),q(x), σ(x) are denoted below. If Ω is an inhomogeneous medium with the density ρ (x), the propagation of waves is described by (1.1) with a(x) = a(x)2 ρ(x), aij(x) = ρ-l(x) δij and q(x) = 0 with the velocity a(x).
Decaying Solutions Of 2mth Order Elliptic Problems
Authors: Allegretto W. , Yu L. S.
Published: December 2010

We consider a semilinear elliptic problem , (n > 2m). Under suitable conditions on f, we show the existence of a decaying positive solution. We do not employ radial arguments. Our main tools are weighted spaces, various applications of the Mountain Pass Theorem and LP regularity estimates of Agmon. We answer an open question of Kusano, Naito and Swanson [Canad. J. Math. 40(1988), 1281-1300] in the superlinear case: , and improve the results of Dalmasso [C. R. Acad. Sci. Paris 308(1989), 411-414] for the case .
Schur and Projective Schur Groups of Number Rings
Authors: Nelis Peter
Published: December 2010

The Schur or projective Schur group of a field consists of the classes of central simple algebras which occur in the decomposition of a group algebra or a twisted group algebra. For number fields, the projective Schur group has been determined in [8], whereas the Schur group is extensively studied in [25]. Recently, some authors have generalized these concepts to commutative rings. One then studies the classes of Azumaya algebras which are epimorphic images of a group ring or a twisted group ring. Though several properties of the Schur or projective Schur group defined in this way have been obtained, they remain rather obscure objects.
The Structure of Stable Components
Authors: Zhang Yingbo , Lang T.
Published: December 2010

Let A be an artin algebra. Let ( be a component of the stable Auslander- Reiten quiver of A. If is periodic, then the structure of G is known. Here, we are going to consider the case when is non-periodic: we will show that is isomorphic to Z with a valued quiver. In particular, there is no cyclic path in .
Additive Functions Monotonic on the Set of Primes II
Authors: De Koninck Jean-Marie , Kátai Imre , Mercier Armel
Published: December 2010

Let L: [1, ∞) → [1, ∞) be a nondecreasing function such that limx→∞L(x) = +∞. Let f= fL be a strongly additive function determined by f(p) = L(p) on the set of primes. In what followsp, p1, p2, …, q, q1, q2, …,P, Q stand for prime numbers, P(n) denotes the largest prime divisor of n. The letters c, c1, c2, … denote suitable positive constants, not necessarily the same at each occurrence. As usual, π(x) denotes the number of primes p ≤ x, while π(x, k, ℓ) is the number of primes p ≤ x such that p ≡ ℓ (mod k).
Collision Local Times and Measure-Valued Processes
Authors: Barlow Martin T. , Evans Steven N. , Perkins Edwin A.
Published: December 2010

We consider two independent Dawson-Watanabe super-Brownian motions,Y1andY2. These processes are diffusions taking values in the space of finite measures on ℝd. We show that ifd ≤ 5then with positive probability there exist timestsuch that the closed supports ofintersect; whereas ifd> 5 then no such intersections occur. For the cased≤ 5, we construct a continuous, non-decreasing measure–valued processL(Y1,Y2), thecollision local time,such that the measure defined by, is concentrated on the set of times and places at which intersections occur. We give a Tanaka-like semimartingale decomposition ofL(Y1,Y2). We also extend these results to a certain class of coupled measurevalued processes. This extension will be important in a forthcoming paper where we use the tools developed here to construct coupled pairs of measure-valued diffusions withpoint interactions.In the course of our proofs we obtain smoothness results for the random measuresthat are uniform int.These theorems use a nonstandard description ofYiand are of independent interest.
The Vitali Integral Convergence Theorem and Uniform Absolute Continuity
Authors: Bator Elizabeth M. , Bilyeu Russell G. , Lewis Paul W.
Published: December 2010

A geometric version of the Vitali integral convergence theorem is established. Parameterized versions of results on uniform absolute continuity in spaces of measures suggested by the convergence theorem are studied.
Strong Boundedness and Strong Convergence in Sequence Spaces
Authors: Buntinas Martin , Tanović-Miller Naza
Published: December 2010

Strong convergence has been investigated in summability theory and Fourier analysis. This paper extends strong convergence to a topological property of sequence spaces E. The more general property of strong boundedness is also defined and examined. One of the main results shows that for an FK-space E which contains all finite sequences, strong convergence is equivalent to the invariance property E = ℓ ν0. E with respect to coordinatewise multiplication by sequences in the space ℓν0 defined in the paper. Similarly, strong boundedness is equivalent to another invariance E = ℓν.E. The results of the paper are applied to summability fields and spaces of Fourier series.
Bounds for Lattice Polytopes Containing a Fixed Number of Interior Points in a Sublattice
Authors: Lagarias Jeffrey C. , Ziegler Günter M.
Published: December 2010

A lattice polytope is a polytope in whose vertices are all in . The volume of a lattice polytope P containing exactly k ≥ 1 points in d in its interior is bounded above by . Any lattice polytope in of volume V can after an integral unimodular transformation be contained in a lattice cube having side length at most n˙n ! V. Thus the number of equivalence classes under integer unimodular transformations of lattice poly topes of bounded volume is finite. If S is any simplex of maximum volume inside a closed bounded convex body K in having nonempty interior, then K⊆ ( n + 2)S — (n+ l)s where mS denotes a nomothetic copy of S with scale factor m, and s is the centroid of S.
Nilpotent Inner Derivations of the Skew Elements of Prime Rings With Involution
Authors: Martindale W. S. , Miers C. Robert
Published: December 2010

Let R be a prime ring with invoution *, of characteristic 0, with skew elements K and extended centroid C. Let a ∈ K be such that (ad a)n =0 on K. It is shown that one of the following possibilities holds: (a) R is an order in a 4-dimensional central simple algebra, (b) there is a skew element λ in C such that , (c) * is of the first kind, n ≡ 0 or n ≡ 3 (mod 4), and . Examples are given illustrating (c).
On Necessary Multiplier Conditions for Laguerre Expansions
Authors: Gasper George , Walter Trebels
Published: December 2010

Necessary multiplier conditions for Laguerre expansions are derived and discussed within the framework of weighted Lebesgue spaces.
On the Range and Invertibility of a Class of Melon Multiplier Transforms III
Authors: McBride A. C. , Spratt W. J.
Published: December 2010

We continue to develop the theory of previous papers concerning transforms corresponding to Mellin multipliers which involve products and/or quotients of Γ-functions. We show that, by working with certain subspaces of Lp,μ consisting of smooth functions, we can simplify considerably the restrictions on the parameters which were necessary in the Lp,μ setting. As a result, operators in our class become homeomorphisms on these subspaces under conditions of great generality.
Tensor Products of Operator Spaces II
Authors: Blecher David P.
Published: December 2010

Together with Vern Paulsen we were able to show that the elementary theory of tensor norms of Banach spaces carries over to operator spaces. We suggested that the Grothendieck tensor norm program, which was of course enormously important in the development of Banach space theory, be carried out for operator spaces. Some of this has been done by the authors mentioned above, and by Effros and Ruan. We give alternative developments of some of this work, and otherwise continue the tensor norm program.
On Certain Stable Wedge Summands of B(𝓩/p)n+
Authors: Harris John C.
Published: December 2010

Campbell and Selick have given a natural decomposition of the cohomology of an elementary abelian p-group over the Steenrod algebra. We study the corresponding stable wedge summands of the classifying space B(𝓩/p)n+using representation theory and explicit idempotents in the group ring 𝓕p[GLn(𝓩/p)].
A Stratification Given by Artin-Rees Estimates
Authors: Wang Ti
Published: December 2010

Let = ℝ or ℂ. Let U be an open subset of n. Let X be a closed analytic subset of U and let Z be a proper closed analytic subset of X. Let M(X;Z) denote the ring of meromorphic functions on Xwhose poles lie in Z. Let M be the families of formal power series generated by a finite sequence ƒi,… ,ƒq ∈ M(X; Z) ⟦ y⟧p (For details, see § 2).
Sequence Entropy and Mild Mixing
Authors: Zhang Qing
Published: December 2010

Entropy characterizations of different spectral and mixing properties of dynamical systems were dealt with by a number of authors (see [5], [6] and [8]).

Given an infinite subset Γ = {tn}of N and a dynamical system (X, β,μ, T) one can define sequence entropy along for any finite Petition ξ, and hΓ(T) —supξ hΓ(T,ξ). In [6] Kushnirenko used sequence entropy to give a characterization of systems with discrete spectrum.
On the Degree of an Analytic Map Germ
Authors: Duszak Zbigniew
Published: December 2010

Let ƒ = (ƒ1,… ,ƒn): (ℝn, 0) → (ℝn, 0) be a real analytic mapping and 0 is isolated in ƒ-1 (0). The aim of this paper is to describe the degree deg0ƒ in terms of parametrizations of irreducible components of the real analytic curve given by the equations ƒ1(x) = ̇̇̇= ƒn-1 (x) = 0 near 0 ∈ ℝn.
C*-Convexity and Matricial Ranges
Authors: Farenick D. R.
Published: December 2010

C* -convex sets in matrix algebras are convex sets of matrices in which matrix-valued convex coefficients are admitted along with the usual scalar-valued convex coefficients. A Carathéodory-type theorem is developed for C*-convex hulls of compact sets of matrices, and applications of this theorem are given to the theory of matricial ranges. If T is an element in a unital C*-algebra , then for every n ∈ N, the n x n matricial range Wn(T) of T is a compact C* -convex set of n x n matrices. The basic relation W1(T) = conv σ-(T) is well known to hold if T exhibits the normal-like quality of having the spectral radius of β T + μ 1 coincide with the norm ||β T + μ 1|| for every pair of complex numbers β and μ. An extension of this relation to the matrix spaces is given by Theorem 2.6: Wn (T) is the C*-convex hull of the n x n matricial spectrum σn(T) of T if, for every B,M ∈ ℳn, the norm of T ⊗ B + 1 ⊗ M in ⊗ ℳn is the maximum value in {||∧⊗B + 1 ⊗M|| : Λ ∈ σn (T)}. The spatial matricial range of a Hilbert space operator is the analogue of the classical numerical range, although it can fail to be convex if n > 1. It is shown in § 3 that if T has a normal dilation N with σ (N) ⊂ σ (T), then the closure of the spatial matricial range of T is convex if and only if it is C*-convex.
Local Minimality of a Lipschitz Extremal
Authors: Zeidan Vera
Published: December 2010

In this paper the question of weak and strong local optimality of a Lipschitz (as opposed to C1 ) extremal is addressed. We show that the classical Jacobi sufficient conditions can be extended to the case of Lipschitz candidates. The key idea for this achievement lies in proving that the “generalized” strengthened Weierstrass condition is equivalent to the existence of a “feedback control” function at which the maximum in the “true” Hamiltonian is attained. Then the Hamilton-Jacobi approach is pursued in order to conclude the result.
A Segal-Langevin Type Stochastic Differential Equation on a Space Of Generalized Functionals
Authors: Kallianpur Gopinath , Mitoma Itaru
Published: December 2010

Let E′ be the dual of a nuclear Fréchet space E and L*(t) the adjoint operator of a diffusion operator L(t) of infinitely many variables, which has a formal expression:

A weak form of the stochastic differential equation

dX(t) = dW(t) + L*(t)X(t)dt

is introduced and the existence of a unique solution is established. The solution process is a random linear functional (in the sense of I. E. Segal) on a space of generalized functionals on E′. The above is an appropriate model for the central limit theorem for an interacting system of spatially extended neurons. Applications to the latter problem are discussed.
A Set-Valued Generalization of Fan's Best Approximation Theorem
Authors: Ding Xie Ping , Tan Kok-Keong
Published: December 2010

Let (E, T) be a Hausdorff topological vector space whose topological dual separates points of E, X be a non-empty weakly compact convex subset of E and W be the relative weak topology on X. If F: (X, W) → 2(E,T) is continuous (respectively, upper semi-continuous if £ is locally convex), approximation and fixed point theorems are obtained which generalize the corresponding results of Fan, Park, Reich and Sehgal-Singh-Smithson (respectively, Ha, Reich, Park, Browder and Fan) in several aspects.
Class Numbers of Real Quadratic Fields, Continued Fractions, Reduced Ideals, Prime-Producing Quadratic Polynomials and Quadratic Residue Covers
Authors: Louboutin S. , Mollin R. A. , Williams H. C.
Published: December 2010

In this paper we consider the relationship between real quadratic fields, their class numbers and the continued fraction expansion of related ideals, as well as the prime-producing capacity of certain canonical quadratic polynomials. This continues and extends work in [10]–[31] and is related to work in [3]–[4].
Fixed Point Theorem and Nonlinear Ergodic Theorem for Nonexpansive Semigroups Without Convexity
Authors: Takahashi Wataru
Published: December 2010

We first prove a nonlinear ergodic theorem for nonexpansive semigroups without convexity in a Hilbert space. Further we prove a fixed point theorem for non-expansive semigroups without convexity which generalizes simultaneously fixed point theorems for left amenable semigroups and left reversible semigroups.
The Ramsey Property for Families of Graphs Which Exclude a Given Graph
Authors: Rödl V. , Sauer N.
Published: December 2010

For graphs A, B and a positive integer r, the relation means that whenever Δ is an r-colouring of the vertices of A, then there is an embedding ϕ of B into A such that Δ ∘ ϕ is constant. A class of graphs has the Ramsey property if, for every , there is an such that . For a given finite graph G, let Forb(G) denote the class of all finite graphs which do not embed G. It is known that, if G is 2-connected, then Forb() has the Ramsey property, and Forb(G) has the Ramsey property if and only if Forb(G) also has the Ramsey property. In this paper we show that if neither G nor its complement is 2-connected, then either (i) G has a cut point adjacent to every other vertex, or (ii) G has a cut point adjacent to every other vertex except one. We show that Forb(G) has the Ramsey property if G is a path of length 2 or 3, but that Forb(G) does not have the Ramsey property if (i) holds and G is not the path of length 2.
Best Polynomial Approximation with Linear Constraints
Authors: Pan K. , Saff E. B.
Published: December 2010

Let A be a (k + 1) × (k + 1) nonzero matrix. For polynomials p ∈ Pn, set and . Let E ⊂ C be a compact set that does not separate the plane and f be a function continuous on E and analytic in the interior of E. Set and . Our goal is to study approximation to f on E by polynomials from Bn(A). We obtain necessary and sufficient conditions on the matrix A for the convergence En(A,f) → 0 to take place. These results depend on whether zero lies inside, on the boundary or outside E and yield generalizations of theorems of Clunie, Hasson and Saff for approximation by polynomials that omit a power of z. Let be such that . We also study the asymptotic behavior of the zeros of and the asymptotic relation between En(f) and En(A,f).
Classification of Atomic Facially Symmetric Spaces
Authors: Friedman Yaakov , Russo Bernard
Published: December 2010

A Banach space satisfying some physically significant geometric properties is shown to be the predual of a JBW*–triple. If one considers the unit ball of this Banach space as the state space of a physical system, the result shows that the set of observables is equipped with a natural ternary algebraic structure. This provides a spectral theory and other tools for studying the quantum mechanical measuring process
On the Minimal Crossing Number and the Braid Index of Links
Authors: Ohyama Yoshiyuki
Published: December 2010

In this paper we prove an inequality that involves the minimal crossing number and the braid index of links by estimating Murasugi and Przytycki’s index for a planar bipartite graph.
Birelative K2 of Groups of Square-Free Order
Authors: Magurn Bruce A.
Published: December 2010

Birelative K2-groups are computed for the fiber squares needed to study K2 and K3 of ℤG when G is a group of square-free order.
Generic Results for Cocycles with Values in a Semidirect Product
Authors: Dajani Karma
Published: December 2010

Let A α B be the semidirect product of two local compact Hausdorff topological groups. We prove that for a nonsingularergodic automorphism T of a Lebesgue probability space, a generic cocycle taking values in A α B is nontrivial and recurrent.
Synergy in the Theories of Gröbner Bases and Path Algebras
Authors: Farkas Daniel R. , Feustel C. D. , Green Edward L.
Published: December 2010

A general theory for Grôbner basis in path algebras is introduced which extends the known theory for commutative polynomial rings and free associative algebras.
The Analytic Rank of a Family of Elliptic Curves
Authors: Mai Liem
Published: December 2010

We study the family of elliptic curves Em X3 + Y3 = m where m is a cubefree integer.

The elliptic curves Em with even analytic rank and those with odd analytic rank are proved to be equally distributed. It is proved that the number of cubefree integers m ≤ X such that the analytic rank of Em is even and ≥ 2 is at least CX2/3-ε, where ε is arbitrarily small and C is a positive constant, for X large enough. Therefore, if we assume the Birch and Swinnerton-Dyer conjecture, the number of all cubefree integers m ≤ X such that the equation X3 + Y3 = m have at least two independent rational solutions is at least CX2/3-ε.
Fraction-Dense Algebras and Spaces
Authors: Hager Anthony W. , Martinez Jorge
Published: December 2010

A fraction-dense (semi-prime) commutative ring A with 1 is one for which the classical quotient ring is rigid in its maximal quotient ring. The fractiondense ƒ- rings are characterized as those for which the space of minimal prime ideals is compact and extremally disconnected. For archimedean lattice-ordered groups with this property it is shown that the Dedekind and order completion coincide. Fractiondense spaces are defined as those for which C(X) is fraction-dense. If X is compact, then this notion is equivalent to the coincidence of the absolute of X and its quasi-F cover. R-embeddings of Tychonoff spaces are re-introduced and examined in the context of fraction-density.
Subgradient Criteria for Monotonicity, The Lipschitz Condition, and Convexity
Authors: Clarke F. H. , Stern R. J. , Wolenski P. R.
Published: December 2010

Let ƒ H → (—∞,∞] be lower semicontinuous, where H is a real Hilbert space. An approach based upon nonsmooth analysis and optimization is used in order to characterize monotonicity of ƒ with respect to a cone, as well as Lipschitz behavior and constancy. The results, which involve hypotheses on the proximal subgradient ∂ πƒ, specialize on the real line to yield classical characterizations of these properties in terms of the Dini derivate. They also give new extensions of these results to the multidimensional case. A new proof of a known characterization of convexity in terms of proximal subgradient monotonicity is also given.
Abstract Witt Rings When Certain Binary Forms Represent Exactly Four Elements
Authors: Cordes Craig M.
Published: December 2010

An abstract Witt ring (R, G) of positive characteristic is known to be a group ring S[Δ] with ﹛1﹜ ≠ Δ ⊆ G if and only if it contains a form〈1,x〉, x ≠1, which represents only the two elements 1 and x. Carson and Marshall have characterized all Witt rings of characteristic 2 which contain binary forms representing exactly four elements. Such results which show R is isomorphic to a product of smaller rings are helpful in settling the conjecture that every finitely generated Witt ring is of elementary type. Here, some special situations are considered. In particular if char(R) = 8, |D〈l, 1〉| = 4, and R contains no rigid elements, then R is isomorphic to the Witt ring of the 2-adic numbers. If char(R) = 4, |D〈l,a〉| = 4 where a ∈ D〈1, 1〉, and R contains no rigid elements, then R is either a ring of order 8 or is the specified product of two Witt rings at least one of which is a group ring. In several cases R is realized by a field.
The A.S. Limit Distribution of the Longest Head Run
Authors: Móri Tamás F.
Published: December 2010

It is well known that the length Zn of the longest head run observed in n tosses with a fair coin is approximately equal to log2n with a stochastically bounded remainder term. Though — log2n does not converge in law, in the present paper it is shown to have almost sure limit distribution in the sense of the a. s. central limit theorem having been studied recently. The results are formulated and proved in a general setup covering other interesting problems connected with patterns and runs such as the longest monotone block or the longest tube of a random walk.
Existence of Invariant Weak Units in Banach Lattices: Countably Generated Left Amenable Semigroup of Operators
Authors: Prabaharan K.
Published: December 2010

Let Σ be a countably generated left amenable semigroup and ﹛Tσ|σ ∈ Σ﹜ be a representation of Σ as a semigroup of positive linear operators on a weakly sequentially complete Banach lattice E with a weak unit e. It is assumed Tσ are uniformly bounded. It is shown that a necessary and sufficient condition for the existence of a weak unit invariant under ﹛Tσ | σ ∈ Σ﹜ is that inf σ∈Σ H(Tσe) > 0 for all nonzero H in the positive dual cone of E.
Markuševič Bases and Corson Compacta in Duality
Authors: Vanderwerff J. , Whitfield J. H. M. , Zizler V.
Published: December 2010

We characterize Banach spaces that admit Markuševič bases with various properties connected with weak countable determining or weak Lindelöf determining of spaces or with various norming properties.
Oscillation and Nonoscillation Properties of Neutral Differential Equations
Authors: Erbe L. H. , Kong Qingkai
Published: December 2010

We obtain a number of new conditions for oscillation of the first order neutral delay equation with nonconstant coefficients of the form

Comparison results are also given as well as conditions for the existence of nonoscillatory solutions.
A Convexity Theorem for Boundaries
of Ordered Symmetric Spaces
Authors: Hilgert Joachim
Published: December 2010

We consider a class of real flag manifolds which occur as Fürstenberg boundaries of ordered symmetric spaces and study the image of associated momentum maps. The presence of the order structure is responsible for much stronger convexity properties than in the general case.
Tauberian- and Convexity Theorems for Certain (N,p,q)-Means
Authors: Kiesel Rüdiger , Stadtmüller Ulrich
Published: December 2010

The summability fields of generalized Nörlund means (N,p*α,p), α ∈ Ν, are increasing with a and are contained in that of the corresponding power series method (P,p). Particular cases are the Cesàro- and Euler-means with corresponding power series methods of Abel and Borel. In this paper we generalize a convexity theorem, which is well-known for the Cesàro means and which was recently shown for the Euler means to a large class of generalized Nörlund means.
Diffusion on Lie Groups II
Authors: Varopoulos N. TH.
Published: December 2010

The heat kernel of an amenable Lie group satisfies either exp. We give a condition on the Lie algebra which characterizes the two cases.