When a network is loaded or constructed interactively, the memory management always has to supply enough units. As already mentioned, the user doesn't have to care about memory allocation and deallocation. During the interactive manipulation of the net, the user can change or delete whole parts of the net. The empty components are grouped in a linked free storage list for later reuse. This is also true for tables like the symbol table. There, identical names (identifiers) are stored only once. A reference counter decides whether an entry can be freed on a delete operation or not. An exhaustive garbage collection is performed when the whole net is deleted.