Authors: Eric Badouel ^1,2; Rodrigue Aimé Djeumen Djatcha ^3,2

• 1 SUpervision of large MOdular and distributed systems
• 2 Laboratoire International de Recherche en Informatique et Mathématiques Appliquées
• 3 Faculté des Sciences [Douala]

We address the problem of component reuse in the context of service-oriented programming and more specifically for the design of user-centric distributed collaborative systems modelled by Guarded Attribute Grammars. Following the contract-based specification of components we devel-opp an approach to an interface theory for the components of a collaborative system in three stages: we define a composition of interfaces that specifies how the component behaves with respect to its environement, we introduce an implementation order on interfaces and finally a residual operation on interfaces characterizing the systems that, when composed with a given component, can complement it in order to realize a global specification.