He was president of the Brazilian Mathematical Society and member on several occasions of international commissions of the IMU (International Mathematical Union) and TWAS (Academy of Sciences for the Developing World).
[2] He has been director of three workshops in his field at the ICTP (Abdus Salam International Centre for Theoretical Physics).
In Brazil he is a recipient of the National Medal for Scientific Merit at the order of Grã-Cruz and a member of the Brazilian Research Group in Commutative Algebra and Algebraic Geometry (1997–2007).
[2] At large he is a John Simon Guggenheim Fellow[4] and has been awarded other fellowships from the Max Planck Institute, Japan Society for Promotion of Science, and the Istituto Nazionale di Alta Matematica.
[2] Simis is of Romanian origin, his parents immigrated to Brazil from Romania in the 1920s.