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CONSTRAINED CONTROLLABILITY IN NON REFLEXIVE BANACH SPACES
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Diomedes Barcenas --- , Venezuela Joe Diestel --- , USAThroughout the literature on optimal control in Banach spaces, hypotheses like “separable and reflexive” are frequently encountered. In this note we consider one such case, studied by Peichl and Schappacher. Using techniques from Banach space theory and the theory of... -
On moduli of convexity and some applications
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Diómedes Bárcenas --- Departamento de Matemáticas, Venezuela Luisa Sánchez --- Departamento de Matemáticas, VenezuelaWe provide some properties of both moduli of convexity δ and β and derive some applications of the modulus β to the geometry of Banach spaces as well as fixed point theory. -
Solutions of Hammerstein equations in the space BV (
) Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: W. Aziz --- Universidad de Los Andes, Venezuela H. Leiva --- Universidad de Los Andes, Venezuela N. Merentes --- Universidad Central de Venezuela, VenezuelaIn this paper we study the existence of solutions for Hammerstein integral equations in the space of two-variables bounded variation functions BV ( ) -
A Dirichlet problem for powers of the generalized Cauchy-Riemann operator
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Antonio Nicola Di Teodoro --- Departamento de Matemáticas Puras y Aplicadas, Venezuela Judith Vanegas --- Departamento de Matemáticas Puras y Aplicadas, VenezuelaIn this paper we solve a Dirichlet problem in ℝ3 for the equation Dnu = 0, where Dn is the n-th power of generalized Cauchy-Riemann operator and u is a Clifford algebra depending on parameters valued function. -
Symmetric Intersections of Rauzy Fractals
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Tarek Sellami --- , , Tunisia Víctor F. Sirvent --- , , VenezuelaIn this article we study symmetric subsets of Rauzy fractals of unimodular irreducible Pisot substitutions. The symmetry considered is reflection through the origin. Given an unimodular irreducible Pisot substitution, we consider the intersection of its Rauzy fractal with the Rauzy... -
On the norm and the essential norm of weighted composition operators acting on the weighted Banach space of analytic functions
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Julio C. Ramos Fernández --- Departamento de Matemáticas, Universidad de Oriente, 6101 Cumaná, Edo, VenezuelaThe objective of this paper is to use known properties of the associated weight to give new estimations of the norm and essential norm of the weighted com- position operators acting between weighted Banach spaces of analytic functions, in terms... -
Composition operator on Λ????p(w) spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: René Erlin Castillo --- Departamento de Matemáticas, Colombia Cruz Suarez --- Departamento de Matemáticas, Venezuela Eduard Trousselot --- Departamento de Matemáticas, VenezuelaIn this paper we give an overview of the Λ????p(w) spaces and also characterize the boundedness and compactness of the composition operator on weighted Lorentz spaces. -
Diet and time-activity budget of White-backed Mousebirds Colius colius in south-western South Africa
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Carlos Bosque --- Departamento de Biología de Organismos, Venezuela Carlos D Bosque --- Departamento de Arquitectura, Venezuela Penn Lloyd --- Percy FitzPatrick Institute of African Ornithology, DST–NRF Centre of Excellence, AustraliaMousebirds (Coliiformes) are unusual in having an exclusively vegetarian diet that includes substantial foliage and by using huddling and sunning to assist thermoregulation. Although previous studies have identified plant species and plant parts consumed by mousebirds, the relative importance of... -
On the continuity of the adjoint of evolution operators
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Diómedes Bárcenas --- , Venezuela Bladismir Leal --- , Ecuador Hugo Leiva --- , Venezuela Ambrosio Tineo Moya --- , VenezuelaBy associating a quasi semigroup to a commutative evolution operator and using techniques from vector measures like the Gel’fand integral and the Radon- Nikodym theorem for Bochner integral, we prove the continuity on [0, +∞) of the adjoint of a... -
Hardy-Littlewood maximal operator on variable Lebesgue spaces with respect to a probability measure
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Jorge Moreno --- , Venezuela Ebner Pineda --- , Ecuador Luz Rodriguez --- , Ecuador Wilfredo O. Urbina --- , USAIn this paper we are going to prove that the Hardy-Litllewood maximal operators on variable Lebesgue spaces L p(·)(µ) with respect to a probability Borel measure µ, are weak type and strong type for two conditions of regularity on the...