Abstract and Applied Analysis 
Volume 2008 (2008), Article ID 374742, 15 pages
doi:10.1155/2008/374742
Research Article

Extension of The Best Approximation Operator in Orlicz Spaces

Ivana Carrizo, Sergio Favier, and Felipe Zó

Instituto de Matemática Aplicada San Luis, UNSL-CONICET, Avda, Ejército de los Andes 950, 5700 San Luis, Argentina

Received 17 December 2007; Accepted 26 February 2008

Recommended by Jean-Pierre Gossez

Abstract

Let (Ω,𝒜,μ) be a probability space and 𝒜 a sub-σ-lattice of the σ-algebra 𝒜. We study an extension of the best ϕ-approximation operator from an Orlicz space Lϕ to the space Lϕ, where ϕ denotes the derivative of the convex, but not necessarily a strictly convex function ϕ. We obtain convergence results when a sequence of σ-algebras n converges to in a suitable way.