Pierre Antoine Grillet has made significant contributions to semigroup theory.
His results have provided the structure of regular semigroups,
and have considerably expanded the theory of commutative semigroups.
He has published 13 definitive research papers in the
Acta Scientiarum Mathematicarum,
and an additional one is accepted for publication.
Some of these papers continue the research initiated by L. Rédei
on congruences of finitely generated commutative semigroups.
The Medal was presented to Pierre Antoine Grillet at 15:00, May 5, 2011
in the Bolyai Institute.
On this occasion he delivered a lecture ``Finitely generated commutative semigroups".