bluuebunny/crossref_metadata_2025_split huggingface dataset:
Representing types in Orlicz and Lorentz sequence spaces
Authors: Bastero Jesús , Raynaud Yves 
Published: November 2008

AbstractThe aim of this paper is to give a representation for the types in some stable Banach sequence spaces, namely in the Orlicz, Lorentz and dual of Lorentz sequence spaces. We also find a characterization for the Lorentz sequence spaces whose class of weakly-null types is locally compact for the topology of uniform convergence on bounded subsets.
Minimal atlases on 3-manifolds
Authors: Gómez-Larrañaga J. C. , González-Acuña F. , Hoste Jim 
Published: November 2008

AbstractIn this paper we investigate the minimal number of charts (spaces homeomorphic to open subsets of ℝ3) needed to cover a closed 3-manifold M3. We prove that this number is two if the Bockstein βω1(M3)∈H2(M3;ℤ) of the first Stiefel-Whitney class of M3 is zero and three if it is not. We state several properties equivalent to βω1(M3) = 0, for example the condition of being covered by two orientable subspaces, and the condition that all torsion elements of H1(M3;ℤ) be represented by orientation-preserving loops. We also show that the non-orientable 3-manifolds which can be covered with two charts are precisely those manifolds which can be described as sewn-up r-link exteriors. These are manifolds obtained by removing from S3 the interiors of two disjoint handlebodies of genus r and then identifying the two boundary components by a homeomorphism.
Essentially unbounded chains in compact sets
Authors: Fremlin D. H. , Kunen K. 
Published: November 2008

We discuss the possible cofinalities of ⊆ *-chains in ℕ which are ⊆ *-unbounded in their topological closures.1. The problem. Throughout this paper, the power set ℕ of the set ℕ of natural numbers will be given its usual compact metrizable topology corresponding to the product topology of {0,1}N. We say that a ⊆ * b if a/b is finite.
Special values of the hypergeometric series
Authors: Joyce G. S. , Zucker I. J. 
Published: November 2008

Recently, several authors [1, 3, 9] have investigated the algebraic and transcendental values of the hypergeometric seriesfor rational parameters a, b, c and algebraic arguments z. This work has led to some interesting new identities such asand where Γ(x) denotes the gamma function.
Tauberian theorems for general power series methods
Authors: Kiesel R. , Stadtmüller U. 
Published: November 2008

Let us assume throughout that (pn) denotes a sequence of reals which satisfiesFor real sequences (sn) with increments an = sn – sn−1 for n ≥ 0,(where s−1 = 0), we consider the power seriesmethod of summability (P), where we sayThe power series methods (P) containthe so-called (Jp)-methods (R = 1)and the Borel-type methods (Bp)(R = ∞). We consider only regular (P)-methods, i.e. sn → s implies sn → s(P). By theorem 5 in [5], p.49, we have regularity if and only ifHere we are interested in the converse conclusion, namely sn → s(P) implies sn → s, which can only be validiffurther conditions, so-called Tauberian conditions are satisfied by (sn). These so-called Tauberian theorems for power series methods have a long history; see e.g. the books [5, 14, 23], and they found new attentionrecently in the papers [6, 18, 19, 20] and [8, 9, 10, 11, 12]. The latter papers contain certain o- Tauberian theorems for all power series methods in question and O-Tauberian theorems, if the weight sequence (pn) can be interpolated by alogarithmico-exponential function g(·)(see e.g. [4]), i.e.
Cohomology with coefficients in symmetric cat-groups. An extension of Eilenberg–MacLane's classification theorem
Authors: Bullejos M. , Carrasco P. , Cegarra A. M. 
Published: November 2008

AbstractIn this paper we use Takeuchy–Ulbrich's cohomology of complexes of categories with abelian group structure to introduce a cohomology theory for simplicial sets, or topological spaces, with coefficients in symmetric cat-groups . This cohomology is the usual one when abelian groups are taken as coefficients, and the main topological significance of this cohomology is the fact that it is equivalent to the reduced cohomology theory defined by a Ω-spectrum, {}, canonically associated to . We use the spaces to prove that symmetric cat-groups model all homotopy type of spaces X with Πi(X) = 0 for all i ╪ n, n + 1 and n ≥ 3, and then we extend Eilenberg–MacLane's classification theorem to those spaces: .
Locating the radical of a triangular operator algebra
Authors: Mastrangelo Laura , Muhly Paul S. , Solel Baruch 
Published: November 2008

AbstractOur primary objective is to give necessary and sufficient conditions for a triangular subalgebra of a groupoid C-algebra to be semisimple, i.e. to have vanishing Jacobson radical. If, in addition, the subalgebra is the analytic subalgebra determined by a real-valued cocycle on the groupoid, then we can give an explicit description of the radical in terms of the cocycle. As a consequence of this analysis, we are able to determine when certain analytic crossed products are semisimple.
Spaces of operators between Fréchet spaces
Authors: Bonet José , Lindström Mikael 
Published: November 2008

AbstractMotivated by recent results on the space of compact operators between Banach spaces and by extensions of the Josefson–Nissenzweig theorem to Fréchet spaces, we investigate pairs of Fréchet spaces (E,F) such that every continuous linear map fromEintoFis Montel, i.e. it maps bounded subsets ofEinto relatively compact subsets ofF. As a consequence of our results we characterize pairs of Köthe echelon spaces (E,F) such that the space of Montel operators fromEintoFis complemented in the space of all continuous linear maps fromEintoF.
Maximal inequalities of Kahane–Khintchine's type in Orlicz spaces
Authors: Peškir Goran 
Published: November 2008

AbstractSeveral maximal inequalities of Kahane–Khintchine's type in certain Orlicz spaces are proved. The method relies upon Lévy's inequality and the technique established in [14] which is obtained by Haagerup–Young–Stechkin's best possible constants in the classical Khintchine inequalities. Moreover by using Donsker's invariance principle it is shown that the numerical constant in the inequality deduced by the method presented is nearly optimal: If is a Bernoulli sequence, and ‖ · ‖ψ denotes the Orlicz norm induced by the function then the following inequality is satisfied:for all a1,…, an and all n ≥ 1, and the best possible numerical constant which can take the place of lies in the interval ]. Sharp estimates of this type are also deduced for some other maximal inequalities in Orlicz spaces discovered in this paper.
An O-Tauberian theorem and a high indices theorem for power series methods of summability
Authors: Borwein David , Kratz Werner 
Published: November 2008

AbstractWe improve known Tauberian results concerning the power series method of summability Jp based on the sequence {pn} by removing the condition that pn be asymptotically logarithmico-exponential. We also prove an entirely new Tauberian result for rapidly decreasing pn.
Equivariant shape theory
Authors: Čerin Zvonko 
Published: November 2008

AbstractEquivariant shape theory is an improvement of equivariant homotopy theory which could be regarded as an equivariant version of Borsuk's shape theory. The main result in this paper is a description of the equivariant shape category ShG whose objects are equivariant spaces or G-spaces, i.e. topological spaces endowed with an action of a given topological group G, and whose morphisms are equivariant homotopy or G-homotopy classes of families of multi-valued functions which we call equivariant multi-nets or G-multi-nets. Previously equivariant shape theories have been described only under the assumptions that the group G is either finite or compact. We also study classes of G-spaces on which equivariant shape and equivariant homotopy coincide, look for conditions under which a G-map f: X → Y is an equivariant shape equivalence, and give some characterizations of G-spaces with trivial equivariant shape.
Zeros of linear combinations of orthogonal polynomials
Authors: Peherstorfer Franz 
Published: November 2008

AbstractLet ψ be a distribution function on [−1,1] from the Szegö-class, which contains in particular all Jacobi weights, and let (pn) be the monic polynomials orthogonal with respect to dψ. Let m(n)∈ℕ, n∈ℕ, be non-decreasing with limn → ∞ (n − m(n)) = ∞, l(n)∈ℕ with 0 ≤ l(n) ≤ m(n), and μj, n ∈ℝ for j = 0, …, m(n), n∈ℕ. It is shown that for each sufficiently large n, has n−l(n) simple zeros in (−1, 1)and l(n) zeros in ℂ\[−1,1] if for n ≥ n0, has m(n) − l(n) zeros in the disc |z| ≤ r < 1, l(n) zeros outside of the disc |z| ≥ R > 1 and where q > 2 max {r, 1/R}. If m(n) is constant for n ≥ n0 then the statement holds even for such polynomials (pn) orthogonal with respect to a distribution dψ satisfying the weak assumption ψ′ > 0 a.e. on [−1, 1]. For linear combinations of polynomials orthogonal on the unit circle corresponding results are derived.
Meromorphic extension of the Selberg zeta function for Kleinian groups via thermodynamic formalism
Authors: Rocha André 
Published: November 2008

AbstractWe prove the existence of a piecewise analytic expanding map associated to certain Kleinian groups without parabolics acting in the 3-dimensional hyperbolic space. These groups have a fundamental domain ℛ with the property that the geodesic planes containing each face are part of the tesselation. We use this map together with the methods of thermodynamic formalism to give another proof that the Selberg zeta function for such groups has a meromorphic extension to ℂ.
Multiplicities in graded rings II: integral equivalence and the Buchsbaum–Rim multiplicity
Authors: Kirby D. , Rees D. 
Published: November 2008

While this paper is principally a continuation of [5], with as its object the application of sections 6 and 7 of that paper to obtain results related to the Buchsbaum–Rim multiplicity, it also has connections with [8] which are the subject of the first of the four sections. These concern integral equivalence of finitely generated R-modules. where R is an arbitrary noetherian ring. We therefore introduce a finitely generated R-module M and relate to it a short exact sequence (s.e.s.),where F is a free module generated by m elements u1,…, um, and L is generated by elements yj, (j = 1, …, n), of F. We identify the elements u1, …, um with a set of indeterminates X1, …, Xm, and F with the R-module S1 of elements of degree 1 of the graded ring S = R[X1, …, Xm].
On sign-representable matroids
Authors: Oxley James , Whittle Geoff 
Published: November 2008

AbstractA matroid M will be called sign-representable if, for every basis B of M, there is a (0, 1, −l)-matrix [Ir|y] representing M over ℚ in which the first r columns correspond to the members of B. The class of sign-representable matroids, which is closely related to the important class of regular matroids, is easily seen to be closed under both duality and the taking of minors. This paper proves several characterizations of the class, including a constructive one, and shows that the excluded minors for the class are U2, 5, U3, 5, the Fano matroid and its dual, and the rank-3 whirl.
On Ingham's Tauberian theorem for partitions
Authors: Auluck F. C. , Haselgrove C. B. 
Published: November 2008

The object of this paper is to extend the range of validity of Ingham's Tauberian theorem for partitions (2). Ingham's theorem deals with many types of partitions, but it cannot be used in some cases of importance. With a slight modification of Ingham's notation we definewhere P(u) is the number of solutions ofin integers ni ≤ 0, and the λi are a given set of numbers, not necessarily integers, such that 0 < λ1 < λ2 <.… If N(u), the number of λi not exceeding u, is given bywhere B > 0, β > 0, and as u → ∞then, according to Ingham's theorem, when u → ∞where
Thomas-Fermi fields for molecules with tetrahedral and octahedral symmetry
Authors: March N. H. 
Published: November 2008

AbstractThe Thomas-Fermi method has been applied to molecules with tetrahedral or octahedral symmetry in the approximation in which the nuclei of the outer atoms are smeared out over the surface of a sphere. Solutions are given for the molecules CH4, CF4, CCl4, SiH4, SiF4 and SF6, and using the results presented here it will not be a difficult matter to obtain the solutions for other molecules if they should be required.A comparison of the results for CH4 with those of Buckingham, Massey and Tibbs shows that whilst for such a light molecule the charge distribution is somewhat poor, the potential is already in good agreement with the results of the Hartree self-consistent field method. For CCl4, however, the approximation of smoothing out all the protons appears to break down. An alternative approximation in which the K and L shell electrons are compressed into the nucleus and the modified nuclear charges smoothed, has been investigated and appears to give more reasonable results.A discussion of the energy has been given, but the method is not sufficiently accurate to be of value for energetic considerations.
Dimension subgroups modulo n
Authors: Moran Siegfried 
Published: November 2008

Let G be an arbitrary group and Zn(G) denote the group algebra of G over the integers modulo n. If δi(G) denotes ith power of the augmentation ideal δ(G) of Zn(G), thenis easily seen to be a normal subgroup of G. It is denoted by Di, n(G) and is called ith dimension subgroup of G modulo n. It can be shown that these dimension subgroups are determined by the dimension subgroups modulo a power of a prime p. Hence we shall restrict our attention to these dimension subgroups.
A remark on topologies for characteristic functions
Authors: Kendall David , Lamperti John 
Published: November 2008

Let M1 denote the set of Borel probability measures on the real line and M1 the space of their Fourier transforms, or ‘characteristic functions’. It is well known that the natural correspondence between M1 and M1 is in fact a homeomorphism, provided M1 is endowed with the usual weak topology relative to bounded continuous functions (which topology can be metrized by the construction of Lévy) and that M1 is given the topology (also metric) appropriate to locally uniform convergence, which we call the ‘compact-open’ topology. In particular, ifwhere μn ∈ M1 (and so φn ∈ M1), then φn(λ)→φ0(λ) uniformly on all compact sets if and only if μn ⇒ μ0 (weak convergence). However, the continuity theorem for characteristic functions implies that even if it is only known that φn(λ)→φ0 pointwise (for all λ), the conclusion that μn ⇒ μ0 is still valid. This raises a question as to whether the pointwise (i.e. product) topology for M1 might not, in fact, be equivalent to the compact-open one, since the corresponding notions of sequential convergence do coincide. The purpose of this note is to show that the answer is negative, even in a much more general setting.
Comparing Id and Haskell in a Monte Carlo photon transport code
Authors: Hammes Jeffrey , Lubeck Olaf , Böhm Wim 
Published: November 2008

AbstractIn this paper we present functional Id and Haskell versions of a large Monte Carlo radiation transport code, and compare the two languages with respect to their expressiveness. Monte Carlo transport simulation exercises such abilities as parsing, input/output, recursive data structures and traditional number crunching, which makes it a good test problem for languages and compilers. Using some code examples, we compare the programming styles encouraged by the two languages. In particular, we discuss the effect of laziness on programming style. We point out that resource management problems currently prevent running realistically large problem sizes in the functional versions of the code.
Formal basis for the refinement of rule based transition systems
Authors: Clark A. N 
Published: November 2008

AbstractThis paper makes a contribution to the refinement of systems which involve search by proposing a simple non-deterministic model for rule based transition systems and using this to define a meaning for rule based refinement which allows each stage of the software development path to be verified with respect to the previous stage. The proposal allows a system which involves search to be specified in terms of all the possible outcomes. Each stage of refinement will introduce complexity to the rules and therefore develop the search space in ever more sophisticated ways. At each stage of the refinement it will be possible to be precise about which collections of outcomes have been deleted, thereby achieving a verified (prototype) implementation.
Some lattice-based scientific problems, expressed in Haskell
Authors: Carpenter D. B. , Glaser H. 
Published: November 2008

AbstractThe paper explores the application of a lazy functional language, Haskell, to a series of grid-based scientific problems—solution of the Poisson equation, and Monte Carlo simulation of two theoretical models from statistical and particle physics. The implementations introduce certain abstractions of grid topology, making extensive use of the polymorphic features of Haskell. Updating is expressed naturally through use of infinite lists, exploiting the laziness of the language. Evolution of systems is represented by arrays of interacting streams.
Haskore music notation – An algebra of music –
Authors: Hudak Paul , Makucevich Tom , Gadde Syam , Whong Bo 
Published: November 2008

AbstractWe have developed a simple algebraic approach to music description and composition calledHaskore. In this framework, musical objects consist of primitive notions such as notes and rests, operations to transform musical objects such as transpose and tempo-scaling, and operations to combine musical objects to form more complex ones, such as concurrent and sequential composition. When these simple notions are embedded into a functional language such as Haskell, rather complex musical relationships can be expressed clearly and succinctly. Exploiting the algebraic properties of Haskore, we have further defined a notion ofliteral performance(devoid of articulation) through whichobservationally equivalentmusical objects can be determined. With this basis many useful properties can be proved, such as commutative, associative, and distributive properties of various operators. An algebra of music thus surfaces.
Domain decomposition algorithms
Authors: Chan Tony F. , Mathew Tarek P. 
Published: November 2008

Domain decomposition refers to divide and conquer techniques for solving partial differential equations by iteratively solving subproblems defined on smaller subdomains. The principal advantages include enhancement of parallelism and localized treatment of complex and irregular geometries, singularities and anomalous regions. Additionally, domain decomposition can sometimes reduce the computational complexity of the underlying solution method.In this article, we survey iterative domain decomposition techniques that have been developed in recent years for solving several kinds of partial differential equations, including elliptic, parabolic, and differential systems such as the Stokes problem and mixed formulations of elliptic problems. We focus on describing the salient features of the algorithms and describe them using easy to understand matrix notation. In the case of elliptic problems, we also provide an introduction to the convergence theory, which requires some knowledge of finite element spaces and elementary functional analysis.
Microsurgical Composite Tissue Transplantation at Difficult Recipient Sites Facilitated by Preliminary Installation of Vein Grafts as Arteriovenous Loops
Authors: Ritter Edmond F. , Anthony James P. , Levin L. Scott , Demas Christopher P. , Klitzman Bruce , Skarada Doug , Serafin Donald 
Published: November 2008

In microvascular surgery when local recipient vessels are inadequate, vein grafting is required. There are several potential inherent disadvantages of immediate vein grafting, including the development of graft thrombosis or leakage, an increased opportunity for technical errors, and an increased number of anastomoses in series. All of these may contribute to a higher failure rate for composite-tissue transplantation requiring vein grafts. The authors hypothesized that in cases where vein grafting is obviously required, the creation of a temporary, looped, arteriovenous fistula (AVF) would reduce the morbidity of vein grafting, by allowing the detection of thrombosis or technical errors predisposing to thrombosis prior to free-tissue transplantation. Since delaying the division of an AVF for 5 or more days may allow time for healing of the endothelium at the AVF anastomotic site, the hypothesis was that composite-tissue transplantation whose vein grafts were installed as an AVF divided in a delayed manner, might have better patency than those in which vein grafts were installed at the time of reconstruction.This study reviews the results of 16 patients (8 females, 8 males) who underwent 17 microvascular reconstructions using AVFs. Patient courses and outcomes were compared between those undergoing immediate (8 patients) and delayed (7 patients) AVF construction, division, and free-tissue transplantation. There was a low patency rate for AVFs which were divided in a delayed fashion (2 of 7 patients, 29 percent), compared with those which were immediately divided (10 of 10, 100 percent). These results suggest that, in spite of a strong theoretical basis for delayed division of the AVF, delayed harvesting of the AVF is empirically associated with a higher thrombosis rate (p = 0.0048, Fishers exact test).
Bioassays for testing effects of Al, Cr and Cd using development in the amphibian Pleurodeles waltl and regeneration in the planarian Dugesia etrusca
Authors: Calevro F. , Campani S. , Filippi C. , Batistoni R. , Deri P. , Bucci S. , Ragghianti M. , Mancino G. 
Published: November 2008

Abstract
Historically, water quality studies have been directed toward obtaining physical and chemical measurements on toxicants occurring in the aquatic environment. At present, bioassays are increasingly used as sensitive indicators of pollutant toxicity, since they are rapid, inexpensive, applicable to a variety of toxicants and allow several acute and chronic endpoints to be assessed simultaneously. The analysis of the potential toxicity of heavy metals was conducted on two aquatic model systems, an amphibian, Pleurodeles waltl, and a freshwater planarian, Dugesia etrusca. Aluminum, chromium and cadmium were chosen since human activity has led to a sharp increase of these metals in the environment. Environmentally realistic and supra-environmental concentrations were assayed in short-term toxicity tests. The effects of these metal ions were evaluated by the analysis of both malformations and lethality in amphibian embryos and alterations to planarian regeneration. Aluminum (0.15, 0.75 and 1.5 mmol 1-1) and Cr (0.75 and 1.5 mmol 1-1) were toxic to P. waltl development and both the ions affected planarian regeneration at concentrations ranging from 0.25 to 1.5 mmol 1-1. Cadmium was highly toxic to amphibian embryos at concentrations ranging from 0.18 to 50 μmol 1-1. This metal ion was also highly toxic to planarians, but it did not significantly affect the regeneration process. The results indicate that bioassays with these two organisms are useful to assess the toxic potential of aquatic pollutants.