English

Weak limits of consecutive projections and of greedy steps

Functional Analysis 2021-12-10 v1

Abstract

Let HH be a Hilbert space. We investigate the properties of weak limit points of iterates of random projections onto K2K\geq 2 closed convex sets in HH and the parallel properties of weak limit points of residuals of random greedy approximation with respect to KK dictionaries. In the case of convex sets these properties imply weak convergence in all the cases known so far. In particular, we give a short proof of the theorem of Amemiya and Ando on weak convergence when the convex sets are subspaces. The question of the weak convergence in general remains open.

Keywords

Cite

@article{arxiv.2112.05094,
  title  = {Weak limits of consecutive projections and of greedy steps},
  author = {Petr A. Borodin and Eva Kopecka},
  journal= {arXiv preprint arXiv:2112.05094},
  year   = {2021}
}