Access Control Lists (ACLs) in the SAP ERP system can be used within the SAP PS module to restrict the access to PS data structures (WBS elements and networks). They were added in SAP ERP ECC 6.0 EhP 3. Before being able to use ACLs, they must be enabled in customizing.
Notifications are a SAP business object that is used in multiple modules to record structured documentation of a piece of information or a problem.
WBS (Work Breakdown Structure) elements are the most important structuring components in the PS module of the SAP ERP system.