Abstract:
We consider the problem of coincidence points of two mappings ψ,φ acting from a metric space (X,ρ) into a space (Y,d) in which a distance d has only one of the properties of the metric: d(y1,y2)=0⇔y1=y2, and is assumed to be neither symmetric nor satisfying the triangle inequality. The question of well-posedness of the equation ψ(x)=φ(x) which determines the coincidence point, is investigated. It is shown that if x=ξ is a solution to this equation, then for any sequence of αi-covering mappings ψi:X→Y and any sequence of βi-Lipschitz mappings φi:X→Y,αi>βi≥0, in the case of convergence {d(φi(ξ),ψi(ξ))→0}, equation ψi(x)=φi(x) has, for any i, a solution x=ξi such that ρ(ξi,ξ)→0. Further in the article, the dependence of the set Coin(t) of coincidence points of mappings ψ(⋅,t),φ(⋅,t):X→Y on a parameter t, an element of the topological space T, is investigated. Assuming that the first of these mappings is α-covering and the second one is β-Lipschitz, we obtain an assertion on upper semicontinuity, lower semicontinuity, and continuity of the set-valued mapping Coin:T⇉X.
Keywords:
well-posedness of equation, continuous dependence on parameter, coincidence point of two mappings, distance, covering mapping.
Citation:
T. V. Zhukovskaya, W. Merchela, “On stability and continuous dependence on parameter of the set of coincidence points of two mappings acting in a space with a distance”, Russian Universities Reports. Mathematics, 27:139 (2022), 247–260
\Bibitem{ZhuMer22}
\by T.~V.~Zhukovskaya, W.~Merchela
\paper On stability and continuous dependence on parameter of the set of coincidence points of two mappings acting in a space with a distance
\jour Russian Universities Reports. Mathematics
\yr 2022
\vol 27
\issue 139
\pages 247--260
\mathnet{http://mi.mathnet.ru/vtamu262}
\crossref{https://doi.org/10.20310/2686-9667-2022-27-139-247-260}