Link: The Open Provenance Model (v1.01)

The OPM is a proposal for a model that will allow systems to exchange provenance information. In the OPM, provenance is modeled as a directed acyclic graph (DAG). The three main types of entities (nodes in the graph) are artifacts (datasets), processes (transformations), and agents (users). Directed edges go from an entity to its dependencies. If there are multiple input artifacts to a process, roles can be used to distinguish among them. Hierarchical accounts can be used to give more detailed provenance.