On semiregularity of mappings

• Published in: Journal of mathematical analysis and applications Vol. 473; no. 2; pp. 811 - 836
• Main Authors: Cibulka, R., Fabian, M., Kruger, A.Y.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.05.2019
• Subjects: Linear openness; Metric semiregularity; Open mapping theorem; Set-valued perturbation; Open mapping theorem; Metric semiregularity; Set-valued perturbation; Linear openness
• ISSN: 0022-247X; 1096-0813
• DOI: 10.1016/j.jmaa.2018.12.071

There are two basic ways of weakening the definition of the well-known metric regularity property by fixing one of the points involved in the definition. The first resulting property is called metric subregularity and has attracted a lot of attention during the last decades. On the other hand, the latter property which we call semiregularity can be found under several names and the corresponding results are scattered in the literature. We provide a self-contained material gathering and extending the existing theory on the topic. We demonstrate a clear relationship with other regularity properties, for example, the equivalence with the so-called openness with a linear rate at the reference point is shown. In particular cases, we derive necessary and/or sufficient conditions of both primal and dual type. We illustrate the importance of semiregularity in the convergence analysis of an inexact Newton-type scheme for generalized equations with not necessarily differentiable single-valued part.