Characterizations of common fixed points of one-parameter nonexpansive semigroups, and convergence theorems to common fixed points

Common Fixed Points of Commutative Semigroups of Nonexpansive Mappings

Let C be a closed convex subset of a Banach space E. A mapping T on C is called a nonexpansive mapping if ‖Tx− Ty‖ ≤ ‖x− y‖ for all x, y ∈ C. We denote by F (T ) the set of fixed points of T . Kirk [21] proved that F (T ) is nonempty in the case that C is weakly compact and has normal structure. See also [3, 4, 5, 14] and others. If C is weakly compact and E has the Opial property, then C has n...

Common Fixed Points of One-parameter Nonexpansive Semigroups in Strictlyconvex Banach Spaces

One of our main results is the following convergence theorem for one-parameter nonexpansive semigroups: let C be a bounded closed convex subset of a Hilbert space E, and let {T(t) : t ∈ R+} be a strongly continuous semigroup of nonexpansive mappings on C. Fix u ∈ C and t1, t2 ∈ R+ with t1 < t2. Define a sequence {xn} in C by xn = (1− αn)/ (t2 − t1) ∫ t2 t1 T(s)xnds+ αnu for n ∈N, where {αn} is ...

On Strong Convergence to Common Fixed Points of Nonexpansive Semigroups in Hilbert Spaces

In this paper, we prove the following strong convergence theorem: Let C be a closed convex subset of a Hilbert space H. Let {T (t) : t ≥ 0} be a strongly continuous semigroup of nonexpansive mappings on C such that ⋂ t≥0 F ( T (t) ) 6= ∅. Let {αn} and {tn} be sequences of real numbers satisfying 0 < αn < 1, tn > 0 and limn tn = limn αn/tn = 0. Fix u ∈ C and define a sequence {un} in C by un = (...

Convergence Theorems of Common Fixed Points for Pseudocontractive Mappings

where E∗ denotes the dual space of E and 〈·, ·〉 denotes the generalized duality pairing. In the sequel, we denote a single-valued normalized duality mapping by j. Throughout this paper, we use F T to denote the set of fixed points of the mapping T . ⇀ and → denote weak and strong convergence, respectively. Let K be a nonempty subset of E. For a given sequence {xn} ⊂ K, let ωω xn denote the weak...

Strong Convergence Theorems of Common Fixed Points for a Family of Quasi--Nonexpansive Mappings