bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Pseudo-Orbit Shadowing Property for Markov Operators in the Space of Probability Density Functions
Authors: Boyarsky Abraham , Góra Pawel 
Published: December 2010

AbstractLet X be a space with two metrics d1 and d2. Let S :(X, d1) → (X, d2) be continuous. We say S has the generalized pseudoorbit shadowing property with respect to the metrics d1 and d2 if for every every δ-pseudo-orbit in d1 can be ∊-shadowed by a true orbit in d2, i.e., if {x0, x1,…} satisfies for all i ≧ 0, then for all i ≧ 0. The main result of this note shows that certain Markov operators P : L1→ L1 have the generalized shadowing property on weakly compact subsets of the space of probability density functions, where d1 is the metric of norm convergence and d2 is the metric of weak convergence. An important class of such operators are the Frobenius-Perron operators induced by certain expanding and nonexpanding maps on the interval. When there is exponential convergence of the iterates to the density, we can express δ in terms of ∊. We also show that, unlike the situation in the space X itself, the generalized shadowing property is valid for all parameters in families of maps and that there is stability of the shadowing property.
Free Objects in Certain Varieties of Inverse Semigroups
Authors: Margolis S. W. , Meakin J. C. , Stephen J. B. 
Published: December 2010

AbstractIn this paper it is shown how the graphical methods developed by Stephen for analyzing inverse semigroup presentations may be used to study varieties of inverse semigroups. In particular, these methods may be used to solve the word problem for the free objects in the variety of inverse semigroups generated by the five-element combinatorial Brandt semigroup and in the variety of inverse semigroups determined by laws of the formxn=xn+ 1. Covering space methods are used to study the free objects in a variety of the form∨whereis a variety of inverse semigroups andis the variety of groups.
One-Parameter Automorphism Groups of the Injective Factor of Type II1 With Connes Spectrum Zero
Authors: Kawahigashi Yasuyuki 
Published: December 2010

AbstractWe construct a one-parameter automorphism group of the injective type II1 factor with Connes spectrum ﹛0﹜ which is not stably conjugate to an infinite tensor product action. We construct a countable family of one-parameter automorphism groups of the injective type II1 factor such that all are stably conjugate but no two are cocycle conjugate.
Group Rings With Hypercentral Unit Groups
Authors: Riley David M. 
Published: December 2010

AbstractLet KG be the group ring of a group G over a field K and let U(KG) be its group of units. If K has characteristic p > 0 and G contains p-elements, then it is proved that U(KG) is hypercentral if and only if G is nilpotent and G′ is a finite p-group.
Minimal and Maximal Operator Theory With Applications
Authors: Wong M. W. 
Published: December 2010

AbstractLetXbe a complex Banach space andAa linear operator fromXintoXwith dense domain. We construct the minimal and maximal operators of the operatorAand prove that they are equal under reasonable hypotheses on the spaceXand operatorA. As an application, we obtain the existence and regularity of weak solutions of linear equations on the spaceX. As another application we obtain a criterion for a symmetric operator on a complex Hilbert space to be essentially self-adjoint. An application to pseudo-differential operators of the Weyl type is given.
Pairwise Balanced Designs with Block Sizes Three and Four
Authors: Colbourn Charles J. , Rosa Alexander , Stinson Douglas R. 
Published: December 2010

AbstractGiven integers ν, a and b, when does a pairwise balanced design on ν elements with a triples and b quadruples exist? Necessary conditions are developed, and shown to be sufficient for all v ≥ 96. An extensive set of constructions for pairwise balanced designs is used to obtain the result.
Nongaussian Limit Distributions of Lacunary Trigonometric Series
Authors: Berkes I. 
Published: December 2010

AbstractIt is a well known fact that for rapidly increasing nkthe sequence , behaves like a sequence of independent random variables; in particular has a limiting Gaussian distribution as N → ∞. Under a certain critical speed this result breaks down and becomes strongly dependent. The purpose of this paper is to investigate the asymptotic behavior of normed sums in the strongly dependent domain; specifically, we construct a large class of nongaussian limit distributions of such sums.
Existence de Solutions au Sens de Carathéodory Pour le Problème de Neumann y″ = f(t, y, y′)
Authors: Guennoun Zine E. A. 
Published: December 2010

AbstractWe announce some existence results and their consequences for the Neumann problem of the nonlinear differential equation: where f: [0, 1] x ℝ2 → ℝ is a Carathéodory function and can grow very rapidly in the y′ variable.
Gaussian and Non–Gaussian Distribution–Valued Ornstein–Uhlenbeck Processes
Authors: Bojdecki Tomasz , Gorostiza Luis G. 
Published: December 2010

Generalized (distribution-valued) Ornstein-Uhlenbeck processes, which by definition are solutions of generalized Langevin equations, arise in many investigations on fluctuation limits of particle systems (eg. Bojdecki and Gorostiza [1], Dawson, Fleischmann and Gorostiza [5], Fernández [7], Gorostiza [8,9], Holley and Stroock [10], Itô [12], Kallianpur and Pérez-Abreu [16], Kallianpur and Wolpert [14], Kotelenez [17], Martin-Löf [19], Mitoma [22], Uchiyama [25]). The state space for such a process is the strong dual Φ′ of a nuclear space Φ. A generalized Langevin equation for a Φ′-valued process X ≡ {Xt} is a stochastic evolution equation of the formwhere {At} is a family of linear operators on Φ and Z ≡ {Zt} is a Φ'-valued semimartingale (in some sense) with independent increments. Equations of the type (1.1) where Z does not have independent increments also arise in applications (eg. [9,14,20]) but here we are interested precisely in the case when Z has independent increments (we restrict the term generalized Langevin equation to this case in accordance with the classical Langevin equation).
Inflection Points of Bessel Functions of Negative Order
Authors: Lorch Lee , Muldoon Martin E. , Szego Peter 
Published: December 2010

AbstractWe consider the positive zeros j″vk, k = 1, 2,…, of the second derivative of the Bessel function Jν(x). We are interested first in how many zeros there are on the interval (0,jν1), where jν1 is the smallest positive zero of Jν(x). We show that there exists a number ƛ = —0.19937078… such that and . Moreover, j″v1 decreases to 0 and j″ν2 increases to j″01 as ν increases from ƛ to 0. Further, j″vk increases in —1 < ν< ∞, for k = 3,4,… Monotonicity properties are established also for ordinates, and the slopes at the ordinates, of the points of inflection when — 1 < ν < 0.
Coloring Ordered Sets to Avoid Monochromatic Maximal Chains
Authors: Duffus D. , Rodl V. , Sauer N. , R. Woodrow  
Published: December 2010

AbstractThis paper is devoted to settling the following problem on (infinite, partially) ordered sets: Is there always a partition (2-coloring) of an ordered set X so that all nontrivial maximal chains of X meet both classes (receive both colors)? We show this is true for all countable ordered sets and provide counterexamples of cardinality N3. Variants of the problem are also considered and open problems specified.
The Structure of the Sequence Spaces of Maddox
Authors: Karl-Goswin  , Grosse-Erdmann  
Published: December 2010

AbstractThe sequence of spaces of Maddox, c0(p), c(p)and l∞(p), are investigated. Here, p — (pk) is a bounded sequence of strictly positive numbers. It is observed that C0(P) is an echelon space of order 0 and that l∞(p) is a co-echelon space of order ∞, while clearly c(p) = c0(p) ⊗ 〈 (1,1,1,…) 〉. This sheds a new light on the topological and sequence space structure of these spaces: Based on the highly developed theory of (co-) echelon spaces all known and various new structural properties are derived.
Extreme and Exposed Points in Orlicz Spaces
Authors: Grzaślewicz R. , Hudzik H. , Kurc W. 
Published: December 2010

AbstractExtreme points of the unit sphere in any Orlicz space over a measure space that contains no atoms of infinite measure are characterized. In the case of a finite-valued Orlicz function and a nonatomic measure space, exposed points of the unit sphere in these spaces are characterized too. Some corollaries and examples are also given.
Lie Ideals and Central Identities With Derivation
Authors: Lanski Charles 
Published: December 2010

AbstractIn this paper we consider various degree two central polynomials with derivation, holding for Lie ideals in prime rings. The results give substantial generalizations of the existing ones on central and semi-centralizing derivations, and show essentially that there are no central identities of the form p(x,y) = c1xyD + C2XDy + c3yxD + C4yDx, where D is a nonzero derivation of the prime ring R.
The Heat Equation on the Spaces of Positive Definite Matrices
Authors: Sawyer P. 
Published: December 2010

AbstractThe main topic of this paper is the study of the fundamental solution of the heat equation for the symmetric spaces of positive definite matrices, Pos(n,R).Our first step is to develop a “False Abel Inverse Transform” which transforms functions of compact support on an euclidean space into integrable functions on the symmetric space. The transform is shown to satisfy the relation is the usual Laplacian with a constant drift).Using this transform, we find explicit formulas for the heat kernel in the cases n = 2 and n = 3. These formulas allow us to give the asymptotic development for the heat kernel as t tends to infinity. Finally, we give an upper and lower bound of the same type for the heat kernel.
Extreme Points of Positive Functionals and Spectral States on Real Banach Algebras
Authors: Srivastav Anand 
Published: December 2010

AbstractExtreme points of positive functionals and spectral states on real commutative Banach algebras are investigated and characterized as multiplicative functionals extending the well-known results from complex to real Banach algebras. As an application a new and short proof of the existence of the Shilov boundary of a real commutative Banach algebra with nonempty maximal ideal space is given.
An Addition Theorem and Some Product Formulas for the Hahn-Exton q-Bessel Functions
Authors: Swarttouw René F. 
Published: December 2010

AbstractIn this paper a q-analogue of Gegenbauer's addition formula for Bessel functions is obtained by using the orthogonality relation for the q-Ultraspherical polynomials of Rogers'. Also some product formulas and an integral representation for the Hahn-Exton q-Bessel functions are obtained.
Frames with Block Size Four
Authors: Rees Rolf S. , Stinson Douglas R. 
Published: December 2010

AbstractWe investigate the spectrum for frames with block size four, and discuss
several applications to the construction of other combinatorial designs.Our main result is that a frame of type hu, having blocks of size four, exists if and
only if u ≥ 5, h ≡ 0 mod 3 and h(u — 1) ≡ 0 mod 4, except possibly where(i)h = 9 and u ∈ ﹛13,17,29,33,93,113,133,153,173,193﹜;(ii)h ≡ 0 mod 12 and u ∈ ﹛8,12﹜,h = 36 and u ∈ ﹛7,18,23,28,33,38,43,48﹜,h = 24 or 120 and u ∈ ﹛7﹜,h = 72 and u ∈ 2Z+ U ﹛n : n ≡ 3 mod4 and n ≤527﹜ U ﹛563﹜; or(iii)h ≡ 6mod l2 and u ∈ (﹛17,29,33,563﹜ U ﹛n : n ≡ 3 or 11 mod 12 and
n ≤ 527﹜ U ﹛n : n ≡ 7 mod 12 and n ≤ 259﹜), h = 18.Additionally, we give a new recursive construction for resolvable group-divisible designs from frames: if there is a resolvable k-GDD of type gu, a k-frame of type ﹛mg)v where u ≥ m + 1, and a resolvable TD(k, mv) then there is a resolvable k-GDD of type (mg)uv. We use this to construct some new resolvable GDDs with group size three and block size four.
Combinatorial Local Planarity and the Width of Graph Embeddings
Authors: Mohar Bojan 
Published: December 2010

AbstractLet G be a graph embedded in a closed surface. The embedding is “locally planar” if for each face, a “large” neighbourhood of this face is simply connected. This notion is formalized, following [RV], by introducing the width ρ(ψ) of the embedding ψ. It is shown that embeddings with ρ(ψ) ≥ 3 behave very much like the embeddings of planar graphs in the 2-sphere. Another notion, “combinatorial local planarity”, is introduced. The criterion is independent of embeddings of the graph, but it guarantees that a given cycle in a graph G must be contractible in any minimal genus embedding of G (either orientable, or non-orientable). It generalizes the width introduced before. As application, short proofs of some important recently discovered results about embeddings of graphs are given and generalized or improved. Uniqueness and switching equivalence of graphs embedded in a fixed surface are also considered.
Oscillations in Higher-Order Neutral Differential Equations
Authors: Philos CH. G. , Purnaras I. K. , Sficas Y. G. 
Published: December 2010

AbstractConsider the n-th order (n ≥ 1 ) neutral differential equation where σ1 < σ 2 < ∞ and μ and η are increasing real-valued functions on [Ƭ1, Ƭ2] and [σ1, σ2] respectively. The function μ is assumed to be not constant on [Ƭ1, Ƭ2] and [Ƭ1, Ƭ2] for every Ƭ ∈ (Ƭ1, Ƭ2) similarly, for each σ ∈ (σ1, σ2), it is supposed that r\ is not constant on [σ1 , σ] and [σ, σ2]. Under some mild restrictions on Ƭ1,- and σ1, (ι = 1,2), it is proved that all solutions of (E) are oscillatory if and only if the characteristic equation of (E) has no real roots.
Curvature Pinching Based on Integral Norms of the Curvature
Authors: Lovrić Miroslav 
Published: December 2010

AbstractA compact Riemannian manifold (M, g) of dimension 3 or higher admits a metric of constant (positive or negative) sectional curvature if the following conditions hold: the diameter is bounded from above, the part of the Ricci curvature which lies below some fixed negative number is bounded in LP norm for p > n/2, and the metric is almost spherical or almost hyperbolic in the LP sense. The idea of the proof is to obtain stronger (i.e. L∞) pinching by deforming the initial metric using the Ricci flow, thus reducing the problem to the theorems of Gromov in the case rg < 0 and of Grove, Karcher and Ruh in the case rg > 0. The reduced curvature tensor changes along the flow according to the heat equation, which implies a weak nonlinear parabolic inequality for its norm. The iteration method of De Giorgi, Nash and Moser is applied to obtain the estimate for the maximum norm of the reduced curvature tensor. The crucial step in the iteration consists of controlling the Sobolev constant of the appropriate imbedding (which also changes along the flow, but behaves well) by the isoperimetric constant, which, in turn, can be bounded in terms independent of the particular manifold.
Cubic Analogues of the Jacobian Theta Function θ(z, q)
Authors: Hirschhorn Michael , Garvan Frank , Borwein Jon 
Published: December 2010

AbstractThere are three modular forms a(q), b(q), c(q) involved in the parametrization of the hypergeometric function analogous to the classical θ2(q), θ3(q), θ4(q) and the hypergeometric function We give elliptic function generalizations of a(q), b(q), c(q) analogous to the classical theta-function θ(z, q). A number of identities are proved. The proofs are self-contained, relying on nothing more than the Jacobi triple product identity
Commutativity Preserving Mappings of Von Neumann Algebras
Authors: Brešar Matej , Robert Miers C. 
Published: December 2010

AbstractA map θ: M —> N where M and N are rings is said to preserve commutativity in both directions if the elements a,b ∊ M commute if and only if θ(a) and θ(b) commute. In this paper we show that if M and N are von Neumann algebras with no central summands of type I1 or I2 and θ is a bijective additive map which preserves commutativity in both directions then θ(x) = cφ(x) +f(x) where c is an invertible element in ZN, the center of N, φ M —> N is a Jordan isomorphism of M onto N, and f is an additive map of M into ZN.
Degenerate Cases of Uniform Approximation by Solutions of Systems with Surjective Symbols
Authors: Gauthier P. M. , Tarkhanov N. N. 
Published: December 2010

AbstractWe prove that each (vector-valued) function in Sobolev space on a compact set K, which in the interior K0 of K satisfies a system of differential equations, can be approximated by solutions in a neighbourhood of K plus sums of potentials of measures supported on the boundary of K. We discuss the particular case where, for all compact sets K, one can dispense with potentials in such approximations
Projective and Injective Hopf Algebras Over the Dyer-Lashof Algebra
Authors: Goerss Paul G. 
Published: December 2010

AbstractThe purpose of this paper is to discuss the existence, structure, and properties of certain projective and injective Hopf algebras in the category of Hopf algebras that support the structure one expects on the homology of an infinite loop space. As an auxiliary project, we show that these projective and injective Hopf algebras can be realized as the homology of infinite loop spaces associated to spectra obtained from Brown-Gitler spectra by Spanier-Whitehead duality and Brown-Comenetz duality, respectively. We concentrate mainly on indecomposable projectives and injectives, and we work only at the prime 2.
Sensitivity and Controllability of Systems Governed by Integral Equations Via Proximal Analysis
Authors: Yezza A. 
Published: December 2010

AbstractIn this paper, we are concerned with the basic problem defined in [9]. Formulas for δV(0)and δ∞V(0),respectively the generalized and asymptotic gradient of the value function at zero, corresponding to an L2 -additive perturbation of dynamics are given. Under the normality condition, δV(0)turns out to be a compact subset of L2, formed entirely of arcs, and V is locally finite and Lipschitz at 0. Moreover, estimations of the generalized directional derivative and Dini's derivative of V at 0 are derived. Supplementary conditions imply that Dini's derivative of V at 0 exists, and V is actually strictly differentiate at this point.
A Modulus for the 3-Dimensional Wave Equation With Noise: Dealing With a Singular Kernel
Authors: Mueller C. 
Published: December 2010

AbstractWe give a modulus of continuity for solutions of the wave equation with a noise term:utt = Δu + a(u) + b(u)G, x ∈ ℝ3where G is a Gaussian noise. This case is more difficult than in lower dimensions because the fundamental solution of the wave equation is singular.
Circulant Graphs and 4-Ranks of Ideal Class Groups
Authors: Hurrelbrink Jurgen 
Published: December 2010

AbstractThis is about results on certain regular graphs that yield information about the structure of the ideal class group of quadratic number fields associated with these graphs. Some of the results can be formulated in terms of the quadratic forms x2+ 27y2, x2+ 32y2, x2+ 64y2.
The Spectrum of Orthogonal Steiner Triple Systems
Authors: Colbourn Charles J. , Gibbons Peter B. , Mathon Rudolf , Mullin Ronald C. , Rosa Alexander 
Published: December 2010

AbstractTwo Steiner triple systems (V, 𝓑) and (V, 𝓓) are orthogonal if they have no triples in common, and if for every two distinct intersecting triples {x,y,z} and {x, y, z} of 𝓑, the two triples {x,y,a} and {u, v, b} in (𝓓 satisfy a ≠ b. It is shown here that if v ≡ 1,3 (mod 6), v ≥ 7 and v ≠ 9, a pair of orthogonal Steiner triple systems of order v exist. This settles completely the question of their existence posed by O'Shaughnessy in 1968.
Unipotent Orbital Integrals of Hecke Functions for GL(n)
Authors: Herb Rebecca A. 
Published: December 2010

AbstractLet G = GL(n, F) where F is a p-adic field, and let 𝓗(G) denote the Hecke algebra of spherical functions on G. Let u1,..., up denote a complete set of representatives for the unipotent conjugacy classes in G. For each 1 ≤ i ≤ p, let	μi be the linear functional on such that μi(f) is the orbital integral of f over the orbit of ui. Waldspurger proved that the μi, 1 ≤ i ≤ p, are linearly independent. In this paper we give an elementary proof of Waldspurger's theorem which provides concrete information about the Hecke functions needed to separate orbits. We also prove a twisted version of Waldspurger's theorem and discuss the consequences for SL(n, F).
Multiparameter Weighted Ergodic Theorems
Authors: Jones Roger L. , Olsen James 
Published: December 2010

AbstractIn this paper we show that multi-dimensional bounded Besicovitch weights are good weights for the pointwise ergodic theorem for Dunford-Schwartz operators and positively dominated contractions of LP. This in particular implies new weighted results for multi-parameter measure preserving point transformations. The proofs show that Besicovitch weights are a very natural class when considered from the operator point of view. We also show that for 1 ≤ r < ∞, the r-bounded Besicovitch classes are all the same, generalizing a result of Bellow and Losert.
New Tauberian Theorems from Old
Authors: Parameswaran Mangalam R. 
Published: December 2010

AbstractA new and very general and simple, yet powerful approach is introduced for obtaining new Tauberian theorems for a summability method V from known Tauberian conditions for V, where V is merely assumed to be linear and conservative. The technique yields the known theorems on the weakening of Tauberian conditions due to Meyer-König and Tietz and others and also improves many of them. Several new results are also obtained, even for classical methods of summability, including analogues of Tauber's second theorem for the Borel and logarithmic methods. The approach yields also new Tauberian conditions for the passage from summability by a method V to summability by a method V', as well as to more general methods of summability like absolute summability or summability in abstract spaces; the present paper however confines itself to ordinary summability.
When is a Distribution of Signs Locally Completable?
Authors: Acquistapace F. , Broglia F. , Fortuna E. 
Published: December 2010

AbstractLet V be an irreducible nonsingular algebraic surface, Y ⊂ V be an algebraic curve and P a point of Y. Suppose a sign distribution is given locally in a neighbourhood of P on some connected components of V — Y. We give an algorithmic criterion to decide whether this sign distribution is induced by a regular function or not. As an application, this criterion enables one to decide whether two semialgebraic sets can be locally separated or not.
Real Projective Representations of SNand AN
Authors: Huang John Q. 
Published: December 2010

AbstractThree main results are obtained in this paper: one generalizes the Atiyah-Bott-Shapiro periodicity equivalence on the category of real Clifford modules, (Theorem 2.2); another establishes the existence of two algebras for real projective representations of the symmetric groupSnand the alternating groupAn, (Theorem 3.2) and determines their structure, (Theorem 6.1); the third describes all the real projective representations ofSnandAnexcept for some small numbersn, (Theorem 7.2).
Conjugacy Classes of Maximal Tori in Simple Real Algebraic Groups and Applications
Authors: Doković Dragomir Ž. , Thăńg Nguyêñ Quôć 
Published: December 2010

AbstractLet G be an almost simple complex algebraic group defined over R, and let G(R) be the group of real points of G. We enumerate the G(R)-conjugacy classes of maximal R-tori of G. Each of these conjugacy classes is also a single G(R)˚-conjugacy class, where G(R)˚ is the identity component of G(R), viewed as a real Lie group. As a consequence we also obtain a new and short proof of the Kostant-Sugiura's theorem on conjugacy classes of Cartan subalgebras in simple real Lie algebras.A connected real Lie group P is said to be weakly exponential (w.e.) if the image of its exponential map is dense in P. This concept was introduced in [HM] where also the question of identifying all w.e. almost simple real Lie groups was raised. By using a theorem of A. Borel and our classification of maximal R-tori we answer the above question when P is of the form G(R)˚.