Many formalisms for the specification for concurrent and distributed systems have emerged. In particular considering boxes and strings approaches. Examples are action calculi, rewriting logic and graph rewriting, bigraphs. The boxes and string metaphor is addressed with different levels of granularity. One of the approaches is to consider a process network as an hypergraph. Based in this general framework, we encode NiMo nets as a class of Annotated hypergraphs. This class is defined by giving the alphabet and the operations used to construct such programs. Therefore we treat only editing operations on labelled hypergraphs and afterwards how this editing operation affects the graph. Graph transformation (execution rules) is not covered here.Postprint (published version
