A sufficient and necessary condition for the existence of fixed points of nonexpansive mappings in Hilbert spaces
Zhao Shi-lian · Journal of Guizhou Normal University · 2009
Using the CQ method,we prove the well-definedness of Ishikawa iterative sequences involving nonexpansive mappings and propose a sufficient and necessary condition for the existence of fixed points of nonexpansive mappings in Hilbert spaces.These results generalize corresponding results of Matsushita and Takahashi.