Cabri-géomètre: Does Dynamic Geometry Software (DGS) Change Geometry and its Teaching and Learning?

The paper starts with remarks on the author's perspective on geometry and Dynamical Geometry Software (DGS). It analyses the way DGS-use influences traditional geometry (part 2). Additionally, taking into account the user of DGS in part 3, the paper highlights changes in the interactions between geometry, the tool computer and DGS and the human user, focussing on changes in the teaching and learning of geometry. The conclusion states that DGS deeply changes geometry if it is taken as a human activity integrating the use of modern instruments like DGS.This revised version was published online in September 2005 with corrections to the Cover Date.