International Journal of Mathematics and Mathematical Sciences 
Volume 21 (1998), Issue 1, Pages 133-137
doi:10.1155/S0161171298000179

Some fixed point theorems for nonconvex spaces

F. Jafari and V. M. Sehgal

 Department of Mathematics, University of Wyoming, Laramie 82071-3036, WY, USA
Received 5 June 1996; Revised 1 November 1996

Abstract

We give a theorem for nonconvex topological vector spaces which yields the classical fixed point theorems of Ky Fan, Kim, Kaczynski, Kelly and Namioka as immediate consequences, and prove a new fixed point theorem for set-valued maps on arbitrary topological vector spaces.