The purpose is to encourage long stays (one to two month(s)) in one of the mathematics laboratories of the Paris-Saclay great campus (see list) creating a pool of potential candidates for a future postdoctoral application. Besides information about the stay (length, location, cost, amount of the requested contribution), the file shall contain a favorable opinion of the PhD supervisor, an invitation letter with agreement of the host research unit director as well as a motivated scientific program. Maximum amount of the contribution: 2300 €.