Renzo Caddeo (born 1946) is a retired professor of geometry and former director of the Department of Mathematics at the University of Cagliari, where he was the organizer of a Masters course dedicated to the visualization of mathematical objects. Before teaching at Cagliari, he has been a research fellow at the University of Bucharest and at the Université de Haute-Alsace, Mulhouse (France). He has held visiting positions at the University of Maryland, at the Katholieke Universiteit Leuven (Belgium), at the Universidad del Pais Vasco (Bilbao) and at the Geometry Center of the University of Minnesota (Minneapolis). His research interests are in differential geometry, in particular in biharmonic maps between Riemannian manifolds and in the surfaces of certain remarkable three-dimensional spaces. He is the author of about 50 articles and of two books, and editor of proceedings of international workshops. Athanase Papadopoulos (born 1957) is Directeur de Recherche at the French Centre National de la Recherche Scientifique. His main fields of interest are geometry and topology, the history and philosophy of mathematics, and mathematics and music. He has held visiting positions at the Institute for Advanced Study, Princeton (1984-85 and 1993-94), USC (1998-1999), CUNY (Ada Peluso Professor, 2014), Brown University (Distinguished visiting professor, 2017), Tsinghua University, Beijing (2018), the State University of Saint Petersburg (as the Lamé Chair) (2019), and has had several month-long visits to the Max-Plank Institute for mathematics (Bonn), the Erwin Schrödinger Institute (Vienna), the Graduate Center of CUNY (New York), the Tata Institute (Bombay), Galatasaray University (Istanbul), the University of Florence (Italy), Fudan University (Shanghai), Gakushuin University (Tokyo) and Presidency University (Calcutta). He is the author of more than 200 published articles and 35 monographs and edited books.
