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Christian Mauduit (1959–2019).**
After working at the CNRS in 1986 and then at the Université de Lyon, Christian Mauduit joined the Laboratoire de mathématiques discrètes in 1993, shortly after Gérard Rauzy founded it at Luminy. A specialist in number theory, he was particularly interested in the equidistribution of sequences such as the Prouhet–Thue–Morse sequence. A Prouhet–Thue–Morse sequence is defined by u0 = 0, u2*n = un and u*2*n*+1 = 1 – *un*. Such sequences have applications in mathematics… and chess.
Together with Joël Rivat, Christian Mauduit proved that, on average, there are as many prime numbers whose decimal digits have an even sum as there are primes for which that sum is odd (this was a conjecture of Gelfond). More broadly, he was an expert on the complexity of integer sequences and on representing integers in different bases. He often worked collaboratively, particularly with the Hungarian mathematicians Pál Erdös and András Sárközy.
Christian Mauduit was also deeply committed to making mathematics accessible to as many people as possible. He established a MATh.en.JEANS course at the university, organized several-day workshops called Hippocampe, headed the IREM of Aix-Marseille from 2006 to 2011, and founded and chaired the association Maths pour tous, which organizes numerous scientific events.
He twice served on the Board of Directors of the SMF and was scientific director of the Centre international de mathématiques pures et appliquées, an association responsible for promoting scientific research in developing countries (see Tangente 142, 2011).