The concept extension defines the name attribute for traces and events. Note that the example XEX file needed uses concept:name attributes for traces and events. For traces, the attribute typically represents some identifier for the case. For events, the attribute typically represents the activity name. The concept extension also defines the instance attribute for events. This is used to distinguish different activity instances in the same trace. This extension can be used to resolve the dilemma shown in Fig. 4.5.