Given the geographical distance, Pierre had participated quite often in the meetings of the Séminaire and had intended to do so even more frequently after retirement from his official duties in autumn 2007. Indeed, we had expected him to join us for the spring meeting in 2008 when we learned the shocking news about the malignant disease that disrupted all his plans and terminated his life in a startingly short period of time.
We remember Pierre as a professional, both for his profound contributions to the field of combinatorics and for his activities in the organization of science. His research articles -- many of them written in collaboration with his students and with colleagues at home and abroad -- and the reference treatise on species theory -- written in collaboration with his colleagues François Bergeron and Gilbert Labelle -- account for the former; his initiative and engagement for the creation of LaCIM, for the SFCA/FPSAC conferences, and his service as a vice dean for research at his faculty testify the latter aspect of his scientific life.
Pierre was indeed a ``québecois pure laine'', but his open and sociable mind won him friends all over the world. He travelled a lot, he was invited to many places, and he made many colleagues come to Montréal to enjoy the working atmosphere that he had decisively helped to create. His visitors also remember him as an active naturalist and happy family man. Those who have known him will confirm the four characteristics, as stated by his family: his kindness, his humour, his perseverance and his professionalism.
Indeed, we have lost a dear friend, and we will always remember him.