I'm looking for a mathematical formalism for a data structure I'm working with so that I can track down relevant theorems and algorithms.

Suppose you have the following:

A directed acyclic graph of topics.

At each topic, there are one or more relations between the topic, items in a set of documents and items in a set of groups.

The groups may be a simple set or they may end up as a DAG. They are used to manage the visibility of the association of a document with a topic.

Only recently have I come across __hypergraphs__, which seem relevant but too general. Is there a formalism for this data structure? If not, can it be described more succinctly in mathematical terms?