Fixed Point Theory and Applications
In hyperconvex metric spaces, we first present a coincidence point theorem for condensing set-valued self-maps. Then we consider the best approximation problem and the best proximity problem for set-valued mappings that are condensing. As an application, we derive a coincidence point theorem for nonself-condensing set-valued maps.
Amini-Harandi, A., Farajzadeh, A.P., O'Regan, D., Agarwal, R.P. Coincidence point, best approximation, and best proximity theorems for condensing set-valued maps in hyperconvex metric spaces (2008) Fixed Point Theory and Applications, 2008, art. no. 543154,