Quantitative metastability of the Tikhonov-Mann iteration for countable families of mappings

Abstract: In this paper, we obtain rates of metastability for the Tikhonov-Mann iteration for countable families of mappings in CAT(0) spaces. This iteration was recently defined by the author in the setting of W-hyperbolic spaces as a generalization of the strongly convergent version of the Krasnoselskii-Mann iteration introduced by Bot and Meier for finding common fixed points of families of nonexpansive mappings in Hilbert spaces, and as an extension of the Tikhonov-Mann iteration for single mappings, for which Leustean and the author obtained rates of asymptotic regularity in W-hyperbolic spaces.