The graph element can also include decomposition and explosion elements that specify the legal subgraph types. Decomposition has an object and a graph, and explosion has an object, relationship or role, plus a graph. The graph elements may contain the definition of the graph type, or an href reference to the graph type defined elsewhere in the file.

<decomposition>
  <object href="#..."/>
  <graph href="#..."/>
</decomposition>
<explosion>
  <object href="#..."/>
  <graph href="#..."/>
</explosion>