The field of weak arithmetics is an application of logical methods to number theory that was developed by mathematicians, philosophers, and theoretical computer scientists. This third volume in the weak arithmetics collection contains nine substantive papers based on lectures delivered during the two last meetings of the conference series Journées sur les Arithmétiques, held in 2014 at the University of Gothenburg, Sweden, and in 2015 at the City University of New York Graduate Center.

Patrick Cégielski is professor in the Département Informatique at Université Paris-Est Créteil. Ali Enayat is professor of logic in the Department of Philosophy, Linguistics and Theory of Science at the University of Gothenburg. Roman Kossak is professor in and chair of the Department of Mathematics and Computer Science at Bronx Community College.