bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudo-Homogeneous Coordinates for Hughes Planes
Authors: Maier Peter , Stroppel Markus 
Published: December 2010

AbstractAmong the projective planes, the class of Hughes planes has received much interest, for several good reasons. However, the existing descriptions of these planes are somewhat unsatisfactory. We introduce pseudo-homogeneous coordinates which at the same time are easy to handle and give insight into the action of the group that is generated by all elations of the desarguesian Baer subplane of a Hughes plane. The information about the orbit decomposition is then used to give a description in terms of coset spaces of this group. Finally, we exhibit a non-closing Desargues configuration in terms of coordinates.
Weak*-Closed Derivations from C[0,1] into L∞[0,1]
Authors: Weaver Nik 
Published: December 2010

AbstractWe show that every weak*-closed derivation from C[0,1] ⊂ L∞[0, 1] into L∞[0, 1] is the inverse of integration against a function in L1[0,1].
On the Reduced Product Construction
Authors: Fantham Peter , James Ioan , Mather Michael 
Published: December 2010

AbstractUnder certain conditions the reduced product space JX of a space X has the same homotopy type as ΩΣX, the loop-space on the suspension of X. Several proofs can be found in the literature. The original proof [6] made unnecessarily strong assumptions. Later, in the last chapter of [3], torn Dieck, Kamps and Puppe gave a proof under much weaker conditions and showed that they could not be further weakened. The question then arose as to whether the reduced product construction could be generalized to provide combinatorial models not only of ΩΣX but also of Ω2Σ2X, Ω3Σ3X and so on. This was answered in the affirmative by May [10], using ideas of Boardman and Vogt [1], and the construction was further developed by Segal [11] and others.The present note, however, is not concerned with these generalizations. Its purpose is to give a simple proof of the original result, without striving for maximum generality, and to show that the same method can be used to prove an equivariant version of the reduced product theorem and hence a fibrewise version. Fibrewise versions of the reduced product theorem have previously been given by Eggar [5] and, more recently, by one of us [8] but it may be useful to have a relatively simple treatment which is adequate for the majority of applications.
Self-Adjoint Fredholm Operators And Spectral Flow
Authors: Phillips John 
Published: December 2010

AbstractWe study the topology of the nontrivial component, , of self-adjoint Fredholm operators on a separable Hilbert space. In particular, if {Bt} is a path of such operators, we can associate to {Bt} an integer, sf({Bt}), called the spectral flow of the path. This notion, due to M. Atiyah and G. Lusztig, assigns to the path {Bt} the net number of eigenvalues (counted with multiplicities) which pass through 0 in the positive direction. There are difficulties in making this precise — the usual argument involves looking at the graph of the spectrum of the family (after a suitable perturbation) and then counting intersection numbers with y = 0.We present a completely different approach using the functional calculus to obtain continuous paths of eigenprojections (at least locally) of the form . The spectral flow is then defined as the dimension of the nonnegative eigenspace at the end of this path minus the dimension of the nonnegative eigenspace at the beginning. This leads to an easy proof that spectral flow is a well-defined homomorphism from the homotopy groupoid of onto Z. For the sake of completeness we also outline the seldom-mentioned proof that the restriction of spectral flow to is an isomorphism onto Z.
Lattice trees and super-Brownian motion
Authors: Derbez Eric , Slade Gordon 
Published: December 2010

AbstractThis article discusses our recent proof that above eight dimensions the scaling limit of sufficiently spread-out lattice trees is the variant of super-Brownian motion calledintegrated super-Brownian excursion(ISE), as conjectured by Aldous. The same is true for nearest-neighbour lattice trees in sufficiently high dimensions. The proof, whose details will appear elsewhere, uses the lace expansion. Here, a related but simpler analysis is applied to show that the scaling limit of a mean-field theory is ISE, in all dimensions. A connection is drawn between ISE and certain generating functions and critical exponents, which may be useful for the study of high-dimensional percolation models at the critical point.
Derivations from Totally Ordered Semigroup Algebras into their Duals
Authors: Blackmore T. D. 
Published: December 2010

AbstractFor a well-behaved measureμ, on a locally compact totally ordered setX, with continuous partμc, we makeLp(X,μc) into a commutative Banach bimodule over the totally ordered semigroup algebraLp(X,μ), in such a way that the natural surjection from the algebra to the module is a bounded derivation. This gives rise to bounded derivations fromLp(X,μ) into its dual module and in particular shows that ifμcis not identically zero thenLp(X,μ) is not weakly amenable. We show that all bounded derivations fromL1(X,μ) into its dual module arise in this way and also describe all bounded derivations from Lp(X,μ) into its dual for 1 <p< ∞ the case thatXis compact andμcontinuous.
Quantum Deformations of Simple Lie Algebras
Authors: Bremner Murray 
Published: December 2010

AbstractIt is shown that every simple complex Lie algebra 𝔤 admits a 1-parameter family 𝔤q of deformations outside the category of Lie algebras. These deformations are derived from a tensor product decomposition for Uq(𝔤)-modules; here Uq(𝔤) is the quantized enveloping algebra of 𝔤. From this it follows that the multiplication on 𝔤q is Uq(𝔤)-invariant. In the special case 𝔤 = (2), the structure constants for the deformation 𝔤 (2)q are obtained from the quantum Clebsch-Gordan formula applied to V(2)q ⊗ V(2)q; here V(2)q is the simple 3-dimensional Uq(𝔤(2))-module of highest weight q2.
Finite Rank Operators and Functional Calculus on Hilbert Modules over AbelianC*-Algebras
Authors: Kucerovsky Dan 
Published: December 2010

AbstractWe consider the problem: IfKis a compact normal operator on a Hilbert moduleE, andf∈C0(SpK) is a function which is zero in a neighbourhood of the origin, isf(K) of finite rank? We show that this is the case if the underlyingC*-algebra is abelian, and that the range off(K) is contained in a finitely generated projective submodule ofE.
The Space of Harmonic Maps from the 2-Sphere to the Complex Projective Plane
Authors: Crawford T. Arleigh 
Published: December 2010

AbstractIn this paper we study the topology of the space of harmonic maps from S2 to ℂℙ2.We prove that the subspaces consisting of maps of a fixed degree and energy are path connected. By a result of Guest and Ohnita it follows that the same is true for the space of harmonic maps to ℂℙn for n ≥ 2. We show that the components of maps to ℂℙ2 are complex manifolds.
A General Approach to Littlewood-Paley Theorems for Orthogonal Families
Authors: Hare Kathryn E. 
Published: December 2010

AbstractA general lacunary Littlewood-Paley type theorem is proved, which applies in a variety of settings including Jacobi polynomials in [0, 1], SU(2), and the usual classical trigonometric series in [0, 2π). The theoremis used to derive new results for Lp multipliers on SU(2) and Jacobi Lp multipliers.
On the Homology of Finite Abelian Coverings of Links
Authors: Hillman J. A. , Sakuma M. 
Published: December 2010

AbstractLet A be a finite abelian group and M be a branched cover of an homology 3-sphere, branched over a link L, with covering group A. We show that H1(M; Z[1/|A|]) is determined as a Z[1/|A|][A]-module by the Alexander ideals of L and certain ideal class invariants.
On Geometric Properties of Orlicz-Lorentz Spaces
Authors: Hudzik H. , Kamińska A. , M. Mastyło  
Published: December 2010

AbstractCriteria for local uniform rotundity and midpoint local uniform rotundity in Orlicz-Lorentz spaces with the Luxemburg norm are given. Strict K-monotonicity and Kadec-Klee property are also discussed.
On Compact Separable Radial Spaces
Authors: Dow Alan 
Published: December 2010

AbstractIf A and B are disjoint ideals on ω, there is a tower preserving σ-centered forcing which introduces a subset of ω which meets every infinite member of A in an infinite set and is almost disjoint fromeverymember of B. We can then produce a model in which all compact separable radial spaces are Fréchet, thus answering a question of P. Nyikos. The question of the existence of compact ccc radial spaces which are not Fréchet was first asked by Chertanov (see [Arh78]).
Asymptotic Existence of Tight Orthogonal Main Effect Plans
Authors: Gallant Robert , Colbourn Charles J. 
Published: December 2010

AbstractOur main result is showing the asymptotic existence of tight OMEPs. More precisely, for each fixed number k of rows, and with the exception of OMEPs of the form 2 × 2 × … 2 × 2s // 4s with s odd and with more than three rows, there are only a finite number of tight OMEP parameters for which the tight OMEP does not exist.
On Permanental Identities of Symmetric and Skew-Symmetric Matrices in Characteristic p
Authors: Valenti Angela 
Published: December 2010

AbstractLet Mn(F) be the algebra of n × n matrices over a field F of characteristic p > 2 and let * be an involution on Mn(F). If s1,…,sr are symmetric variables we determine the smallest r such that the polynomialis a *-polynomial identity of Mn(F) under either the symplectic or the transpose involution. We also prove an analogous result for the polynomialwhere k1,…,kr, are skew variables under the transpose involution.
Genericity of Certain Classes of Unitary and Self-Adjoint Operators
Authors: Choksi J. R. , Nadkarni M. G. 
Published: December 2010

AbstractIn a paper [1], published in 1990, in a (somewhat inaccessible) conference proceedings, the authors had shown that for the unitary operators on a separable Hilbert space, endowed with the strong operator topology, those with singular, continuous, simple spectrum, with full support, forma dense Gδ. A similar theoremfor bounded self-adjoint operators with a given normbound (omitting simplicity) was recently given by Barry Simon [2], [3], with a totally different proof. In this note we show that a slight modification of our argument, combined with the Cayley transform, gives a proof of Simon’s result, with simplicity of the spectrum added.
Class Number One and Prime-Producing Quadratic Polynomials Revisited
Authors: Mollin R. A. 
Published: December 2010

AbstractOver a decade ago, this author produced class number one criteria for real quadratic fields in terms of prime-producing quadratic polynomials. The purpose of this article is to revisit the problem from a new perspective with new criteria.We look at the more general situation involving arbitrary real quadratic orders rather than the more restrictive field case, and use the interplay between the various orders to provide not only more general results, but also simpler proofs.
The Periodic Radical of Group Rings and Incidence Algebras
Authors: Parmenter M. M. , Spiegel E. , Stewart P. N. 
Published: December 2010

AbstractLet R be a ring with 1 and P(R) the periodic radical of R. We obtain necessary and sufficient conditions for P(RG) = 0 when RG is the group ring of an FC group G and R is commutative. We also obtain a complete description of when I(X, R) is the incidence algebra of a locally finite partially ordered set X and R is commutative.
Remarks on Certain Metaplectic Groups
Authors: Sun Heng 
Published: December 2010

AbstractWe study metaplectic coverings of the adelized group of a split connected reductive group G over a number field F. Assume its derived group G′ is a simply connected simple Chevalley group. The purpose is to provide some naturally defined sections for the coverings with good properties which might be helpful when we carry some explicit calculations in the theory of automorphic forms on metaplectic groups. Specifically, we1.construct metaplectic coverings of G(A) from those of G′(A);2.for any non-archimedean place v, show the section for a covering of G(Fv) constructed from a Steinberg section is an isomorphism, both algebraically and topologically in an open subgroup of G(Fv);3.define a global section which is a product of local sections on a maximal torus, a unipotent subgroup and a set of representatives for the Weyl group.
How the Roots of a Polynomial Vary with its Coefficients: A Local Quantitative Result
Authors: Beauzamy Bernard 
Published: December 2010

AbstractA well-known result, due to Ostrowski, states that if , then the roots (xj) of P and (yj) of Q satisfy , where n is the degree of P and Q. Though there are cases where this estimate is sharp, it can still be made more precise in general, in two ways: first by using Bombieri’s norm instead of the classical l1 or l2 norms, and second by taking into account the multiplicity of each root. For instance, if x is a simple root of P, we show that instead of . The proof uses the properties of Bombieri’s scalar product andWalsh Contraction Principle.
Operators with Closed Range, Pseudo-Inverses, and Perturbation of Frames for a Subspace
Authors: Christensen Ole 
Published: December 2010

AbstractRecent work of Ding and Huang shows that if we perturb a bounded operator (between Hilbert spaces) which has closed range, then the perturbed operator again has closed range. We extend this result by introducing a weaker perturbation condition, and our result is then used to prove a theorem about the stability of frames for a subspace.
Conjugate Radius and Sphere Theorem
Authors: Paeng Seong-Hun , Yun Jong-Gug 
Published: December 2010

AbstractBessa [Be] proved that for given n and i0, there exists an depending on n, i0 such that if M admits a metric g satisfying , then M is diffeomorphic to the standard sphere. In this note, we improve this result by replacing a lower bound on the injectivity radius with a lower bound of the conjugate radius.
Mellin Transforms of Mixed Cusp Forms
Authors: Choie Youngju , Lee Min Ho 
Published: December 2010

AbstractWe define generalized Mellin transforms of mixed cusp forms, show their convergence, and prove that the function obtained by such a Mellin transform of a mixed cusp form satisfies a certain functional equation. We also prove that a mixed cusp form can be identified with a holomorphic form of the highest degree on an elliptic variety.
Spaces of Quasi-Measures
Authors: Grubb D. J. , LaBerge Tim 
Published: December 2010

AbstractWe give a direct proof that the space of Baire quasi-measures on a completely regular space (or the space of Borel quasi-measures on a normal space) is compact Hausdorff. We show that it is possible for the space of Borel quasi-measures on a non-normal space to be non-compact. This result also provides an example of a Baire quasi-measure that has no extension to a Borel quasi-measure. Finally, we give a concise proof of theWheeler-Shakmatov theorem, which states that if X is normal and dim(X) ≤ 1, then every quasi-measure on X extends to a measure.
Lie Derivations in Prime Rings With Involution
Authors: Swain Gordon A. , Blau Philip S. 
Published: December 2010

AbstractLet R be a non-GPI prime ring with involution and characteristic ≠ 2, 3. Let K denote the skew elements of R, and C denote the extended centroid of R. Let δ be a Lie derivation of K into itself. Then δ = ρ + ∊ where ∊ is an additive map into the skew elements of the extended centroid of R which is zero on [K, K], and ρ can be extended to an ordinary derivation of ⧼K⧽ into RC, the central closure.
Characterizations of Simple Isolated Line Singularities
Authors: Zaharia Alexandru 
Published: December 2010

AbstractA line singularity is a function germ with a smooth 1-dimensional critical set . An isolated line singularity is defined by the condition that for every x ≠ 0, the germ of f at (x, 0) is equivalent to . Simple isolated line singularities were classified by Dirk Siersma and are analogous of the famous A − D − E singularities. We give two new characterizations of simple isolated line singularities.
The Commutant of an Abstract Backward Shift
Authors: Barnes Bruce A. 
Published: December 2010

AbstractA bounded linear operator T on a Banach space X is an abstract backward shift if the nullspace of T is one dimensional, and the union of the null spaces of Tk for all k ≥ 1 is dense in X. In this paper it is shown that the commutant of an abstract backward shift is an integral domain. This result is used to derive properties of operators in the commutant.
Exponential Laws for the Nachbin Ported Topology
Authors: Boyd C. 
Published: December 2010

AbstractWe show that for U and V balanced open subsets of (Qno) Fréchet spaces E and F that we have the topological identityAnalogous results for the compact open topology have long been established. We also give an example to show that the (Qno) hypothesis on both E and F is necessary.
Extensions of Continuous and Lipschitz Functions
Authors: Matoušková Eva 
Published: December 2010

AbstractWe show a result slightly more general than the following. Let K be a compact Hausdorff space, F a closed subset of K, and d a lower semi-continuous metric on K. Then each continuous function ƒ on F which is Lipschitz in d admits a continuous extension on K which is Lipschitz in d. The extension has the same supremum norm and the same Lipschitz constant.As a corollary we get that a Banach space X is reflexive if and only if each bounded, weakly continuous and norm Lipschitz function defined on a weakly closed subset of X admits a weakly continuous, norm Lipschitz extension defined on the entire space X.
James-Hopf Invariants, Anick’s Spaces, and the Double Loops on Odd Primary Moore Spaces
Authors: Neisendorfer Joseph 
Published: December 2010

AbstractUsing spaces introduced by Anick, we construct a decomposition into indecomposable factors of the double loop spaces of odd primary Moore spaces when the powers of the primes are greater than the first power. If n is greater than 1, this implies that the odd primary part of all the homotopy groups of the 2n + 1 dimensional sphere lifts to a mod pr Moore space.
Infinite Classes of Covering Numbers
Authors: Bluskov I. , Greig M. , Heinrich K. 
Published: December 2010

AbstractLet D be a family of k-subsets (called blocks) of a v-set X(v). Then D is a (v, k, t) covering design or covering if every t-subset of X(v) is contained in at least one block of D. The number of blocks is the size of the covering, and the minimum size of the covering is called the covering number. In this paper we consider the case t = 2, and find several infinite classes of covering numbers. We also give upper bounds on other classes of covering numbers.
Weighted Mean Operators on lp
Authors: Borwein David 
Published: December 2010

AbstractAbstract. The weightedmean matrix Ma is the triangular matrix {ak/An}, where an > 0 and An := a1 + a2 + … + an. It is proved that, subject to ncan being eventually monotonic for each constant c and to the existence of for 1 < p < ∞ if and only if α < p.
Obstructions to 𝒵-Stability for Unital Simple C*-Algebras
Authors: Gong Guihua , Jiang Xinhui , Su Hongbing 
Published: December 2010

AbstractLet 𝒵 be the unital simple nuclear infinite dimensional C*-algebra which has the same Elliott invariant as ℂ, introduced in [9]. A C*-algebra is called 𝒵-stable if A ≅ A ⊗ 𝒵. In this note we give some necessary conditions for a unital simple C*-algebra to be 𝒵-stable.
The Generating Degree of ℂp
Authors: Alexandru Victor , Popescu Nicolae , Zaharescu Alexandru 
Published: December 2010

AbstractThe generating degree gdeg(A) of a topological commutative ring A with char A = 0 is the cardinality of the smallest subset M of A for which the subring [M] is dense in A. For a prime number p, denotes the topological completion of an algebraic closure of the field of p-adic numbers. We prove that gdeg() = 1, i.e., there exists t in such that [t] is dense in . We also compute where A(U) is the ring of rigid analytic functions defined on a ball U in . If U is a closed ball then = 2 while if U is an open ball then is infinite. We show more generally that is finite for any affinoid U in ℙ1() and is infinite for any wide open subset U of ℙ1().
A Technique of Studying Sums of Central Cantor Sets
Authors: Anisca Razvan , Ilie Monica 
Published: December 2010

AbstractThis paper is concernedwith the structure of the arithmetic sum of a finite number of central Cantor sets. The technique used to study this consists of a duality between central Cantor sets and sets of subsums of certain infinite series. One consequence is that the sum of a finite number of central Cantor sets is one of the following: a finite union of closed intervals, homeomorphic to the Cantor ternary set or an M-Cantorval.
Quantization of Bending Deformations of Polygons In , Hypergeometric Integrals and the Gassner Representation
Authors: Kapovich Michael , Millson John J. 
Published: December 2010

AbstractThe Hamiltonian potentials of the bending deformations of n-gons instudied in [KM] and [Kly] give rise to a Hamiltonian action of the Malcev Lie algebra𝓟nof the pure braid groupPnon the moduli spaceMrofn-gon linkages with the side-lengthsr = (r1, … , rn)in. Ife∈Mris a singular point wemay linearize the vector fields in𝓟nate. This linearization yields a flat connection ∇ on the spaceof n distinct points on. We show that the monodromy of ∇ is the dual of a quotient of a specialized reduced Gassner representation.
Exceptional Sets of Slices for Functions From the Bergman Space in the Ball
Authors: Jakóbczak Piotr 
Published: December 2010

AbstractLet BN be the unit ball in and let f be a function holomorphic and L2-integrable in BN. Denote by E(BN, f) the set of all slices of the form , where L is a complex one-dimensional subspace of , for which is not L2-integrable (with respect to the Lebesgue measure on L). Call this set the exceptional set for f. We give a characterization of exceptional sets which are closed in the natural topology of slices.
An Analogue of Napoleon’s Theorem in the Hyperbolic Plane
Authors: McKay Angela 
Published: December 2010

AbstractThere is a theorem, usually attributed to Napoleon, which states that if one takes any triangle in the Euclidean Plane, constructs equilateral triangles on each of its sides, and connects the midpoints of the three equilateral triangles, one will obtain an equilateral triangle. We consider an analogue of this problem in the hyperbolic plane.
Spectral Transformations of the Laurent Biorthogonal Polynomials, II. Pastro Polynomials
Authors: Vinet Luc , Zhedanov Alexei 
Published: December 2010

AbstractWe continue to study the simplest closure conditions for chains of spectral transformations of the Laurent biorthogonal polynomials (LBP). It is shown that the 1-1-periodic q-closure condition leads to the LBP introduced by Pastro. We introduce classes of semi-classical and Laguerre-Hahn LBP associated to generic closure conditions of the chain of spectral transformations.
Some Adjunction Properties of Ample Vector Bundles
Authors: Ishihara Hironobu 
Published: December 2010

AbstractLet ε be an ample vector bundle of rank r on a projective variety X with only log-terminal singularities. We consider the nefness of adjoint divisors KX +(t−r) det ε when t ≥ dim X and t > r. As an application, we classify pairs (X, ε) with cr-sectional genus zero.
Matching of Weighted Orbital Integrals for Metaplectic Correspondences
Authors: Mezo Paul 
Published: December 2010

AbstractWe prove an identity between weighted orbital integrals of the unit elements in the Hecke algebras of GL(r) and its n-fold metaplectic covering, under the assumption that n is relatively prime to any proper divisor of every 1 ≤ j ≤ r.