August 2012 : Antoine Deza (Mac Master University, Canada) visited CERMICS from July 1 to August 31. He worked in collaboration with F. Meunier and P. Sarabezolles (CERMICS) on a combinatorial approach to colourful simplicial depth conjecture. The conjecture has been verified in dimension 4, and the known lower bounds in higher dimensions have been strenghtened. The results have been published in Siam J. on Discrete Maths. in 2014.