Symbolic representation of user-defined time granularities

In the recent literature on time representation, an effort has been made to characterize the notion of time granularity and the relationships between granularities, in order to have a common framework for their specification, and to allow the interoperability of systems adopting different time granularities. The paper considers the mathematical characterization of finite and periodical time granularities, and it identifies a user-friendly symbolic formalism which captures exactly that class of granularities. This is achieved by a formal analysis of the expressiveness of well known symbolic representation formalisms