Generalized centers of finite sets in Banach spaces.
Generalizing the arithmetic geometric mean - a hapless computer experiment.
Geometric properties of Banach spaces and the existence of nearest and farthest points.
Good approximation in metrizable locally convex spaces involving a set of nonlinear functionals
Greedy approximation and the multivariate Haar system
We study nonlinear m-term approximation in a Banach space with regard to a basis. It is known that in the case of a greedy basis (like the Haar basis in , 1 < p < ∞) a greedy type algorithm realizes nearly best m-term approximation for any individual function. In this paper we generalize this result in two directions. First, instead of a greedy algorithm we consider a weak greedy algorithm. Second, we study in detail unconditional nongreedy bases (like the multivariate Haar basis in ,...