iStar2.0 was delivered in 2016 with the intention of becoming a standard de facto for the i* community. It includes a lightweight definition of the language adorned with a metamodel (in the form of a UML class diagram) that is useful for most purposes. However, in some contexts, a more precise algebraic definition including a notion of satisfaction is needed. This paper presents such elements. First, an algebraic definition of iStar2.0. Then, some auxiliary operations. Last, the notion of satisfaction over i* models using first order logic. Satisfaction is still defined mainly in a syntactic form, relying upon the satisfaction of the individual intentional elements comprising the model.

Peer Reviewed