A selfmapping f of a metric space (X, d)
is nonexpansive (ε-nonexpansive) if
d(f(x),
f(y)) ≤ d(x,
y) for all x, y ∊ X
(respectively if d(x, y) < ε). In [1],
M. Edelstein proved that a nonexpansive mapping f of
En admits a fixed point provided the f-closure of
En (i.e. the set of all points which are cluster points of
{fn(x)} for some x) is nonempty. R.
D. Holmes [2] considered commutative semigroups of selfmappings of a metric
space and obtained fixed point theorems for such semigroups under certain
contractivity conditions.