Yasunori Kimura, Masashi Toyoda:
Fixed point theorem in ball spaces and Caristi's fixed point theorem.
Journal of Nonlinear and Convex Analysis
23
:185
-189
, 2022
3.
Koji Aoyama, Masashi Toyoda:
Fixed point theorem for a Meir-Keeler type mapping in a metric space with a transitive relation.
Transylvanian Journal of Mathematics and Mechanics
14
:1
-9
, 2022