12. A computer-readable storage medium according to one of claim 1 and 2 , wherein the description of abstract constraints is inserted in a sub-part of the abstract part and is adapted to describe an abstract structure of messages exchanged.
12. A computer-readable storage medium according to one of claim 1 and 2 , wherein the description of abstract constraints is inserted in a sub-part of the abstract part and is adapted to describe an abstract structure of messages exchanged. 13. A computer-readable storage medium according to claim 12 , wherein the abstract part includes a sub-part adapted to declare at least one elementary message pointing to the description of the abstract constraints.