Under some assumptions on the pair , we study equivalence between interpolation properties of linear operators and monotonicity conditions for a pair (Y,Z) of rearrangement invariant quasi-Banach spaces when the extreme spaces of the interpolation are . Weak and restricted weak intermediate spaces fall within our context. Applications to classical Lorentz and Lorentz-Orlicz spaces are given.
A morphism of a category which is simultaneously an epimorphism and a monomorphism is called a bimorphism. The category is balanced if every bimorphism is an isomorphism. In the paper properties of bimorphisms of several categories are discussed (pro-homotopy, shape, proper homotopy) and the question of those categories being balanced is raised. Our most interesting result is that a bimorphism f:X → Y of is an isomorphism if Y is movable. Recall that is the full subcategory of consisting of...
We prove sharp end forms of Holmstedt's reiteration theorem which are closely connected with a general form of Gehring's Lemma. Reverse type conditions for the Hardy-Littlewood-Pólya order are considered and the maximal elements are shown to satisfy generalized Gehring conditions. The methods we use are elementary and based on variants of reverse Hardy inequalities for monotone functions.
Given an orientation-preserving homeomorphism of the plane, a rotation number can be associated with each locally attracting fixed point. Assuming that the homeomorphism is dissipative and the rotation number vanishes we prove the existence of a second fixed point. The main tools in the proof are Carath´eodory prime ends and fixed point index. The result is applicable to some concrete problems in the theory of periodic differential equations.
We show that coefficients of residue formulas for characteristic numbers associated to a smooth toral action on a manifold can be taken in a quotient field This yields canonical identities over the integers and, reducing modulo two, residue formulas for Stiefel Whitney numbers.
En este trabajo se presenta un algoritmo de resolución del problema de Knapsack basado en el análisis de una secuencia de problemas, derivados del original, desarrollando un criterio que relaciona la admisibilidad entre ellos. Este algoritmo es de enumeración implícita; examinando sucesivamente soluciones lexicográficamente ordenadas con criterios de dominancia y optimalidad. Mediante experiencias computacionales se comparan los resultados de este algoritmo con otros bien conocidos.
We present a generalized degree theory for continuous maps f: (D, ∂D) → (E, E0), where E is a normed vectorial space, D is an open subset of R x E such that p(D) is bounded in R and f is a compact perturbation of the second projection p: R x E → E.
The purpose of our work is to find explicit formulae for the computation of some characteristic classes of smooth principal bundles P: P --> B, in terms of local invariants at a singular subset AG of B, associated to a smooth action of a compact Lie group G on P. This singular subset, AG, is defined as the set of points x in B whose isotropy subgroups Gx have dimension at least one.
We extend the shape index, introduced by Robbin and Salamon and Mrozek, to locally defined maps in metric spaces. We show that this index is additive. Thus our construction answers in the affirmative two questions posed by Mrozek in [12]. We also prove that the shape index cannot be arbitrarily complicated: the shapes of q-adic solenoids appear as shape indices in natural modifications of Smale's horseshoes but there is not any compact isolated invariant set for any locally defined map in a locally...
One can find in the mathematical literature many recent papers studying the generalized Apostol-Bernoulli, Apostol-Euler and Apostol-Genocchi polynomials, defined by means of generating functions. In this article we clarify the range of parameters in which these definitions are valid and when they provide essentially different families of polynomials. In particular, we show that, up to multiplicative constants, it is enough to take as the “main family” those given by and as an “exceptional family”...
Let w be a generalized Jacobi weight on the interval [-1,1] and, for each function f, let Sf denote the n-th partial sum of the Fourier series of f in the orthogonal polynomials associated to w. We prove a result about uniform boundedness of the operators S in some weighted L spaces. The study of the norms of the kernels K related to the operators S allows us to obtain a relation between the Fourier series with respect to different generalized Jacobi weights.
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