The department of mathematics is in building NO, on the Campus de la Plaine, of the Université libre de Bruxelles. The geometry group is on the 7th floor. This map shows NO, as well as the metro station Delta and the stop for the number 71 bus. The number 95 also stops a short walk from the department. See the STIB website for more information on public transport in Brussels.
Polished ammonite fossil, by Kara Stenberg, Creative Commons licence CC BY-NC 2.0.