Metric Subregularity and the Proximal Point Method

We examine the linear convergence rates of variants of the proximal point method for finding zeros of maximal monotone operators. We begin by showing how metric subregularity is sufficient for linear convergence to a zero of a maximal monotone operator. This result is then generalized to obtain convergence rates for the problem of finding a common zero of multiple monotone operators by considering randomized and averaged proximal methods.Comment: 14 page

Metric regularity and systems of generalized equations

The paper is devoted to a revision of the metric regularity property for mappings between metric or Banach spaces. Some new concepts are introduced: uniform metric regularity and metric multi-regularity for mappings into product spaces, when each component is perturbed independently. Regularity criteria are established based on a nonlocal version of Lyusternik-Graves theorem due to Milyutin. The criteria are applied to systems of generalized equations producing some "error bound" type estimates. © 2007 Elsevier Inc. All rights reserved

Directional metric regularity of multifunctions

In this paper, we study relative metric regularity of set-valued mappings with emphasis on directional metric regularity. We establish characterizations of relative metric regularity without assuming the completeness of the image spaces, by using the relative lower semicontinuous envelopes of the distance functions to set-valued mappings. We then apply these characterizations to establish a coderivative type criterion for directional metric regularity as well as for the robustness of metric regularity

Openness of mappings

V práci studujeme zobecněné verze metrické regularity, například nelineární a směrová regularita. Rovněž studujeme podobné zobecnění metrické subregularity a semiregularity a odvozujeme postačují podmínky pro tyto vlastnosti v případě jednoznačných zobrazení v konečné dimenzi. Prvním cílem práce je definovat metrickou regularitu, metrickou subregularitu a metrickou semiregularity jednoznačných i mnohoznačných zobrazení. Formulujeme několik ekvivalentních vlastností a také uvedeme postačující i nutné podmínky pro jejich platnost. Dále se zabýváme stabilitou zmíněných vlastností vzhledem k jednoznačné i mnohoznačné perturbaci. Druhým cílem je poskytnout postačující podmínky pro směrovou semiregularitu a semiregularitu s vazbou jednoznačných zobrazení v konečné dimenzi založených na aproximaci lineárním zobrazením a svazkem lineárních zobrazení. Zaměříme se na výpočet modulů (semi)regularity lineárních zobrazení. Posledním cílem je zobecnit kritéria Ioffeho typu do kvazimetrických prostorů a tím získat kritéria pro nelineární a směrové verze uvedených vlastností.ObhájenoIn this thesis, we study criteria for generalized notions of metric regularity for single-valued and set-valued mappings, such as nonlinear and directional versions and the combination of both. We also study similar generalizations of metric subregularity and semiregularity and we focus on the criteria for constrained and directional semiregularity of single-valued mappings in finite dimensional spaces. The first aim of this thesis is to discuss metric regularity, metric subregularity, and metric semiregularity of both single-valued and set-valued mappings. Several equivalent properties are formulated and the sufficient as well as the necessary conditions are presented. Further, we discuss the stability of these properties with respect to single-valued and set-valued perturbations. The second aim is to provide sufficient conditions for directional and constrained semiregularity of single-valued mappings in finite dimensional spaces via an approximation by a linear mapping and by a bunch of linear mappings. We also focus on the computation of directional (semi)regularity modulus of linear mappings. The last aim is to extend Ioffe-type criteria to quasi-metric spaces and thus to achieve criteria for nonlinear and directional versions of the mentioned properties