Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6417850 | Journal of Mathematical Analysis and Applications | 2014 | 17 Pages |
Abstract
Let V be an n-dimensional real Banach space and let λ(V) denote its absolute projection constant. For any NâN, Nâ¥n defineλnN=supâ¡{λ(V):dimâ¡(V)=n,Vâlâ(N)}. The aim of this paper is to determine minimal projections with respect to l1-norm as well as with respect to lâ-norm for subspaces given by solutions of certain extremal problems. As an application we show that for any n,NâN, Nâ¥n there exists an n-dimensional subspace Vnâl1(N) such thatλnN=λ(Vn,l1(N)). Also we calculate relative and absolute projection constants of some subspaces of codimension two in l1(N) and lâ(N) for Nâ¥3 being odd natural number. Moreover, we show that for any odd natural number nâ¥3,λnn+1
Related Topics
Physical Sciences and Engineering
Mathematics
Analysis
Authors
Alberto Castejón, Grzegorz Lewicki,