Fabien Durand is Full Professor in Mathematics at Universite de Picardie Jules Verne. His interests include topological dynamical systems and the relations with theoretical computer science. He is currently the president of the Societe Mathematique de France. Dominique Perrin is Emeritus Professor in Mathematics and Computer Science at Universite Gustave Eiffel. He is (co)author or editor of a number of books including Profinite Semigroups and Symbolic Dynamics, Codes and Automata, Infinite Words and Combinatorics on Words (under the pseudonym Lothaire). He is a member of Academia Europea.