A quadratic rate of asymptotic regularity for CAT(0)-spaces
نویسنده
چکیده
In this paper we obtain a quadratic bound on the rate of asymptotic regularity for the Krasnoselski-Mann iterations of nonexpansive mappings in CAT(0)-spaces, whereas previous results guarantee only exponential bounds. The method we use is to extend to the more general setting of uniformly convex hyperbolic spaces a quantitative version of a strengthening of Groetsch’s theorem obtained by Kohlenbach using methods from mathematical logic (so-called “proof mining”).
منابع مشابه
Asymptotic aspect of quadratic functional equations and super stability of higher derivations in multi-fuzzy normed spaces
In this paper, we introduce the notion of multi-fuzzy normed spaces and establish an asymptotic behavior of the quadratic functional equations in the setup of such spaces. We then investigate the superstability of strongly higher derivations in the framework of multi-fuzzy Banach algebras
متن کاملGeodesic metric spaces and generalized nonexpansive multivalued mappings
In this paper, we present some common fixed point theorems for two generalized nonexpansive multivalued mappings in CAT(0) spaces as well as in UCED Banach spaces. Moreover, we prove the existence of fixed points for generalized nonexpansive multivalued mappings in complete geodesic metric spaces with convex metric for which the asymptotic center of a bounded sequence in a bounded closed convex...
متن کاملNonexpansive Iterations in Uniformly Convex W -hyperbolic Spaces
We propose the class of uniformly convex W -hyperbolic spaces with monotone modulus of uniform convexity (UCW -hyperbolic spaces for short) as an appropriate setting for the study of nonexpansive iterations. UCW -hyperbolic spaces are a natural generalization both of uniformly convex normed spaces and CAT (0)-spaces. Furthermore, we apply proof mining techniques to get effective rates of asympt...
متن کاملEffective metastability for modified Halpern iterations in CAT(0) spaces
*Correspondence: kohlenbach@mathematik. tu-darmstadt.de Department of Mathematics, Technische Universität Darmstadt, Schlossgartenstrasse 7, Darmstadt, 64289, Germany Abstract We examine convergence results for modified Halpern iterations due to Cuntavepanit and Panyanak (Fixed Point Theory Appl. 2011:869458, 2011). Following Kohlenbach and Leuştean (Adv. Math. 231:2525-2556, 2012), we extract ...
متن کاملNon-linear ergodic theorems in complete non-positive curvature metric spaces
Hadamard (or complete $CAT(0)$) spaces are complete, non-positive curvature, metric spaces. Here, we prove a nonlinear ergodic theorem for continuous non-expansive semigroup in these spaces as well as a strong convergence theorem for the commutative case. Our results extend the standard non-linear ergodic theorems for non-expansive maps on real Hilbert spaces, to non-expansive maps on Ha...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2005