Mariatul Kiftiah, S.Si., M.Sc. is a lecturer from the Department of Mathematics who obtained a master’s degree in the field of Mathematical Analysis from Gadjah Mada University, Yogyakarta. Mariatul Kiftiah’s research interests include fixed point theory in metric spaces, modular spaces, and their extensions in modular metric spaces. In his research, several types of contraction mapping have been defined in these spaces. Furthermore, the existence and singularity of fixed points for contraction mapping was successfully proven by Mariatul Kiftiah. Apart from that, Mariatul Kiftiah is also interested in conducting research in the field of Applied Mathematics, especially topics related to Optimization.