Hierarchical Models of Provenance

There is general agreement that we need to understand provenance at various levels of granularity; however, there appears, as yet, to be no general agreement on what granularity means. It can refer both to the detail with which we can view a process or the detail with which we view the data. We describe a simple and straightforward method for imposing a hierarchical structure on a provenance graph and show how it can, if we want, be derived from the program whose execution created that graph.