In the frame of the Prosfer and JoRISS programs (cooperation between ENS de Lyon and ECNU Shanghai), several students are doing their PhD co-supervised by researchers of the two institutions. Two of them, Zhu Fangchun (fourth year) and Shao Mingyu (second year), are questioning the role of dynamic geometry environment for the teaching of geometry. A third PhD student is involved in this seminar, Valentin Roussel. This seminar takes profit of the scientific stay of Nathalie Sinclair, an international expert of this domain, for discussing the current state of the two PhD and, more generally, for discussing the 'didactical challenge of dynamic geometry environments'. Nicolas Balacheff, an other expert of this domain, will propose a cross view on these diverse contributions as a closing reaction.

The three PhD are developed in the frame of the S2HEP laboratory, and the EPIC doctoral school. Zhu Fangchun is supervised by Xu Binyan in ECNU, and Sophie Soury-Lavergne in ENS de Lyon. Shao Mingyu is supervised by Bao Jiansheng in ECNU, by Jana Trgalova and Luc Trouche in ENS de Lyon. Valentin Roussel is supervised, in Lyon 1 University, by Jana Trgalova.