On the existence of fixed points for some discontinuous operators. (English) Zbl 0705.47045
The author discusses fixed point theorems for operators T in a Banach space satisfying
\[
\| Tx-Ty\| \leq a\| x-y\| +b\| x- Tx\| +b\| y-Ty\| +c\| x-Ty\| +c\| y-Tx\|.
\]
Related results are due to W. R. Derrick and L. Nova G. [see the preceding review].
Reviewer: J.Appell
MSC:
47H10 | Fixed-point theorems |