The Items element defines the items on the BA diagram and the relations between them.
Item (BusinessApplication)
Unlike Form and BusinessRecord, the Item element of BusinessApplication does not modify the behavior of an existing item, it defines a new item, with a new name, inheriting from a default item.
BasicItem
The BasicItem element defines a new item, with a new name. It does not modify the behavior of an existing item.
Relation
The Relation element defines a BA diagram relation.