\documentclass[12pt]{article}
\usepackage{amsmath,amssymb,amsfonts}
\begin{document}
In this paper, for commuting pair consisting of a single-valued mapping $t$ and multi-valued mapping $T$, which are satisfying Suzuki?s condition $C$, in a $CAT(0)$ space $X$, we look for a solution to the problem of existence of $z \in K \subset X$ such that $z=t(z)\in T(z)$, where $K$ is a bounded closed convex subset of $X$. Our results improve and extend some recent results of Shahzad and Markin (2008) [12].
\end{document}