Abstract
In this paper we extend to UCW-hyperbolic spaces the quantitative asymptotic regularity results for the alternating Halpern–Mann iteration obtained by Dinis and the second author for CAT(0) spaces. These results are new even for uniformly convex normed spaces. Furthermore, for a particular choice of the parameter sequences, we compute linear rates of asymptotic regularity in W-hyperbolic spaces and quadratic rates of T- and U-asymptotic regularity in CAT(0) spaces.
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Alexander, S., Kapovitch, V., Petrunin, A.: An Invitation to Alexandrov Geometry. CAT(0) Spaces. Springer, Berlin (2019)
Ariza-Ruiz, D., Leuştean, L., López-Acedo, G.: Firmly nonexpansive map**s in classes of geodesic spaces. Trans. Am. Math. Soc. 366, 4299–4322 (2014)
Boţ, R.I., Csetnek, E.R., Meier, D.: Inducing strong convergence into the asymptotic behaviour of proximal splitting algorithms in Hilbert spaces. Optim. Methods Softw. 34, 489–514 (2019)
Bridson, M., Haefliger, A.: Metric Spaces of Non-positive Curvature. Springer, Berlin (1999)
Cheval, H., Leuştean, L.: Quadratic rates of asymptotic regularity for the Tikhonov-Mann iteration. Optim. Methods Softw. 37, 2225–2240 (2022)
Cheval, H., Kohlenbach, U., Leuştean, L.: On modified halpern and tikhonov-mann iterations. J. Optim. Theory Appl. 197, 233–251 (2023)
Dinis, B., Pinto, P.: Strong convergence for the alternating Halpern-Mann iteration in CAT(0) spaces. ar**v:2112.14525; accepted for publication in SIAM J. Optim. (2023)
Ferreira, F., Leuştean, L., Pinto, P.: On the removal of weak compactness arguments in proof mining. Adv. Math. 354, 106728 (2019)
Goebel, K., Reich, S.: Uniform Convexity, Hyperbolic Geometry, and Nonexpansive Map**s. Marcel Dekker Inc., New York (1984)
Groetsch, C.W.: A note on segmenting Mann iterates. J. Math. Anal. Appl. 40, 369–372 (1972)
Halpern, B.: Fixed points of nonexpanding maps. Bull. Ame Math. Soc. 73, 957–961 (1967)
Kim, T.H., Xu, H.K.: Strong convergence of modified Mann iterations. Nonlinear Anal. 61, 51–60 (2005)
Kohlenbach, U.: Uniform asymptotic regularity for Mann iterates. J. Math. Anal. Appl. 279, 531–544 (2003)
Kohlenbach, U.: Some logical metatheorems with applications in functional analysis. Trans. Am. Math. Soc. 357, 89–128 (2005)
Kohlenbach, U.: Applied Proof Theory: Proof Interpretations and their Use in Mathematics. Springer, Berlin (2008)
Kohlenbach, U., Leuştean, L.: Asymptotically nonexpansive map**s in uniformly convex hyperbolic spaces. J. Eur. Math. Soc. 12, 71–92 (2010)
Kohlenbach, U., Leuştean, L.: Effective metastability of Halpern iterates in CAT(0) spaces. Adv. Math. 231, 2526–2556 (2012)
Krasnoselskii, M.A.: Two remarks on the method of successive approximations. Uspehi Mat. Nauk (N.S.) 10, 123–127 (1955)
Leuştean, L.: A quadratic rate of asymptotic regularity for CAT(0)-spaces. J. Math. Anal. Appl. 325, 386–399 (2007)
Leuştean, L.: Nonexpansive iterations in uniformly convex \(W\)-hyperbolic spaces. In: Leizarowitz, A., Mordukhovich, B.S., Shafrir, I., Zaslavski, A. (eds.) Nonlinear Analysis and Optimization I : Nonlinear Analysis. American Mathematical Society, pp. 193–209 (2010)
Leuştean, L., Pinto, P.: Quantitative results on a Halpern-type proximal point algorithm. Comput. Optim. Appl. 79, 101–125 (2021)
Mann, W.R.: Mean value methods in iteration. Proc. Am. Math. Soc. 4, 506–510 (1953)
Sabach, S., Shtern, S.: A first order method for solving convex bilevel optimization problems. SIAM J. Optim. 27, 640–660 (2017)
Xu, H.-K.: Iterative algorithms for nonlinear operators. J. Lond. Math. Soc. 66, 240–256 (2002)
Yao, Y., Zhou, H., Liou, Y.-C.: Strong convergence of a modified Krasnoselski-Mann iterative algorithm for non-expansive map**s. J. Appl. Math. Comput. 29, 383–389 (2009)
Acknowledgements
The first author thanks Adriana Nicolae for useful discussions on the subject of the paper. The second author was supported by the German Science Foundation (DFG Project KO 1737/6-2).
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Leuştean, L., Pinto, P. Rates of asymptotic regularity for the alternating Halpern–Mann iteration. Optim Lett 18, 529–543 (2024). https://doi.org/10.1007/s11590-023-02002-y
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DOI: https://doi.org/10.1007/s11590-023-02002-y