Abstract:
We study properties of set-valued mappings F admitting a continuous
selection f which is a continuous ϵ-selection (from the set
of ϵ-closest points) for the images F(x)(x∈X).
This is interpreted as an ϵ-selection for continuously varying
sets in a space with continuously varying norms. We deduce new fixed-point
theorems from the results obtained. We also study geometric-topological
properties of sets all of whose r-neighbourhoods possess a continuous
ϵ-selection for every ϵ>0. We obtain a characterization
of such sets.
This publication is cited in the following 7 articles:
A. R. Alimov, K. S. Ryutin, I. G. Tsar'kov, “Existence, uniqueness, and stability of best and near-best approximations”, Russian Math. Surveys, 78:3 (2023), 399–442
I. G. Tsar'kov, “Approximative properties of sets and continuous selections”, Sb. Math., 211:8 (2020), 1190–1211
I. G. Tsar'kov, “Weakly monotone sets and continuous selection in asymmetric spaces”, Sb. Math., 210:9 (2019), 1326–1347
I. G. Tsar'kov, “Continuous selections for metric projection operators and for their generalizations”, Izv. Math., 82:4 (2018), 837–859
I. G. Tsar'kov, “Continuous selections in asymmetric spaces”, Sb. Math., 209:4 (2018), 560–579
I. G. Tsar'kov, “New Criteria for the Existence of a Continuous ε-Selection”, Math. Notes, 104:5 (2018), 727–734
I. G. Tsar'kov, “Weakly monotone sets and continuous selection from a near-best approximation operator”, Proc. Steklov Inst. Math., 303 (2018), 227–238