Torrey M. Gallagher is an Assistant Professor of Mathematics at Monmouth University (New Jersey, USA). His research interests include metric fixed point theory, Banach space geometry, and functional analysis.

Víctor Pérez-García is a full time professor at Faculty of Mathematics, University of Veracruz, Mexico. Areas of interest: Functional Analysis, Discrete Mathematics.

¿ukasz Piasecki is an Associate Professor at the Institute of Mathematics at Maria Curie-Sk lodowska University (Lublin, Poland). His research interests include metric fixed point theory and Banach space theory.