We study various regularity properties, including subregularity and semiregularity, of set-valued mappings acting in extended quasi-metric spaces. It turns out that this abstract framework allows to unify criteria for the usual (sub/semi) regularity as well as their directional and Hölder counterparts. Ioffe-type critera are obtained by applying a general version of the Ekeland's variational principle. We provide a self-contained material gathering and extending the existing theory on the topic. We (briefly) illustrate the importance of these criteria for applications. For example, we consider local convergence of a directional version of a Newton-type method for solving a generalized equation which may be applied when the usual (non-directional) regularity does not hold.

Contact details are reproduced from the original publication and may be historical.

Radek Cibulka

NTIS and Dept. of Mathematics, Faculty of Applied Sciences, University of West Bohemia, 306 14 Pilsen, Czech Republic

cibi@kma.zcu.cz

Tomáš Roubal

NTIS and Dept. of Mathematics, Faculty of Applied Sciences, University of West Bohemia, 306 14 Pilsen, Czech Republic

roubalt@ntis.zcu.cz
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R. Cibulka, T. Roubal. “Ioffe-Type Criteria in Extended Quasi-Metric Spaces.” Journal of Convex Analysis 27 (2020), No. 1, 205–226. https://doi.org/10.68381/jca27012