Abstract
We show that if is a bounded open set in a complete
space
, and if
is nonexpansive, then
always has a fixed point if there exists
such that
for all
. It is also shown that if
is a geodesically bounded closed convex subset of a complete
-tree with
, and if
is a continuous mapping for which
for some
and all
, then
has a fixed point. It is also noted that a geodesically bounded complete
-tree has the fixed point property for continuous mappings. These latter results are used to obtain variants of the classical fixed edge theorem in graph theory.