Characterization of regularity via variational stability of alternating projections sequences

Fuente: arXiv
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Main Authors: Battistoni, Francesco, Daniilidis, Aris, De Bernardi, Carlo Alberto, Miglierina, Enrico
Format: Preprint
Published: 2025
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_version_ 1866914526790680576
author Battistoni, Francesco
Daniilidis, Aris
De Bernardi, Carlo Alberto
Miglierina, Enrico
author_facet Battistoni, Francesco
Daniilidis, Aris
De Bernardi, Carlo Alberto
Miglierina, Enrico
contents The notion of regular pair $(A,B)$ for two nonempty closed convex subsets $A$ and~$B$ of a Hilbert space $\H$ was introduced by Borwein and Bauschke in 1993 to ensure convergence (in norm) of the alternating projection method to some point of the best approximation set. In 2022, De Bernardi and Miglierina showed that regularity of the pair $(A,B)$ guarantees, additionally, the convergence for any variational perturbation of the alternating projection method, provided the corresponding best approximation sets are bounded. In this work, we show that the converse assertion is also true. Moreover, this converse assertion holds without requiring the best approximation sets to be bounded.
format Preprint
id arxiv_https___arxiv_org_abs_2511_07953
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Characterization of regularity via variational stability of alternating projections sequences
Battistoni, Francesco
Daniilidis, Aris
De Bernardi, Carlo Alberto
Miglierina, Enrico
Optimization and Control
47J25 (Primary) 90C25, 90C48 (Secondary)
The notion of regular pair $(A,B)$ for two nonempty closed convex subsets $A$ and~$B$ of a Hilbert space $\H$ was introduced by Borwein and Bauschke in 1993 to ensure convergence (in norm) of the alternating projection method to some point of the best approximation set. In 2022, De Bernardi and Miglierina showed that regularity of the pair $(A,B)$ guarantees, additionally, the convergence for any variational perturbation of the alternating projection method, provided the corresponding best approximation sets are bounded. In this work, we show that the converse assertion is also true. Moreover, this converse assertion holds without requiring the best approximation sets to be bounded.
title Characterization of regularity via variational stability of alternating projections sequences
topic Optimization and Control
47J25 (Primary) 90C25, 90C48 (Secondary)
url https://arxiv.org/abs/2511.07953