In a series of papers, we have attempted to develop a model for "living" systems. This study has been undertaken some 15 years ago to find a common language between a physician (Jean-Paul Vanbremeersch) and a "categorician" (Andrée Ehresmann), trying together to understand problems related to complexity. This site proposes a synthetic presentation of the various concepts introduced during this work.

The subject: a lemon beside an orange does not remain a lemon and the orange an orange to become fruits. Mathematics follows this law, us also.

G. Braque