A Happening is a Classifier for dynamic entities. A Course Event is a kind of Event that occurs as part of the lifecycle of a Course, such as Start Event, End Event. The Common Infrastructure provides a predefined library of Course Events. A Happening Part is a kind of Course Part that is also a Typed Part where the type is a Happening. It is a stage or interval in a development or Course. Happening Parts are different from other Course Parts as they are the only one that have occurence trace at runtime. An Event Condition is a Condition for specifying that an Event must occur in the context of a particular Happening Over Time for the condition to hold. For instance, a condition can be on the eruption (instance of Event) of a particular volcano (instance of Happening Over Time). A Happening Over Time is a Happening for dynamic entities that are treated as extending over time and that are contexts for Events. A Immediate Succession is a kind of Succession that has the following execution semantic: successor immediately follows its predecessor A Gateway is a kind of Course Part representing potentially complex specifications of how dynamic individuals playing Happening Parts are ordered in time. The particular specifications are given in subtypes. At runtime, Gateways don't have any execution trace. A Fact Change Condition refers to general propositions becoming true or false due to changes in M0 facts. It is used to integrate with models of rules. A Time Event specifies a point in time that is a source of interest. A Cycle Event is a kind of Time Event that define the occurrence of a cycle in time. A Relative TimeDate Event is a kind of TimeDate Event that defines a change in time for a relative start point in time. Parallel Join is a Gateway indicating that the parts (in the sense of individuals) following it happen after the parts preceding them A TimeDate Event is a kind of Time Event that manifest a date or time change. A Fact Change is a kind of Event that manifests a change in the evaluation of a Statement. Exclusive Split is a Gateway indicating that exactly one of the part following it will occur after the part preceding it A Succession is a Directed Part Connection that organizes Course Parts in series in the context of a Course. A Succession indicates that one Course Part "follows" another in time, and possibly establishes constraints on such followings. It can order the Event Part of its Happening Parts such as their Start or End. Succession allows any combination of Event Part to be connected. End -> Start Start -> Start Start -> Abort etc. A Succession doesn't need to have Happening Part on its ends, it can have untyped course parts also, such as Gateway, but it must have something on each end. For convenience, a Succession that does not specify source event part or target event part will have the same effect as a Succession where these are respectively the End and Start . A Time Event Condition is a kind of Event Condition that is based on the occurrence of a Time Event. A Time Event Condition is specified by referring to a Clock. An Exclusive Join is a Gateway indicating that the part following it will occur after each part that occurs preceding it. A Course Part is a kind of Connectable Element that defines a stage in a Course. It can be connected to Succession as a predecessor or successor element. A Course is an ordered Succession of Happening Parts A Course is a Composite that has connections representing that one part of the course "follows" another in time, and possibly establishes constraints on such followings (Succession). A Clock is a kind of Happening Over Time that produces Time Events. An Event Part identifies Event (such as Start Event or End Event) for an individual Course. An Event Part is also a Happening Part, enabling it to be connected by Successions. An Event is a Happening for dynamic entities occurring at a point in time. Parallel Split is a Gateway that indicates that the dynamic individuals playing parts following them happen after the dynamic individuals playing the part preceding them.