Note: Features on nonoccurrence classes that should be vars when
specialized to occurrences (including "top-level" features) require a
constraint on Occurrence to make them vars.
  
Readonly features
  Readonly features on nonoccurrence classes
    Must be vars when specialized to occurrence classes (unless
    they're intended to be features only of lives).

    Links::Link:participant:Anything[2..*] nonunique ordered;
    Links::BinaryLink::source/target: Anything[1] nonunique subsets participant;
      Another data point for the JIRA discussion on participants as (non) vars.

    Metaobjects::Metaobject::annotatedElement:Element[1..*]
    Metaobjects::SemanticMetadata::redefines annotatedElement : Type[1]

    Clocks::universalClock:UniversalClockLife[1]
    Observation::defaultMonitor[1] : DefaultMonitorLife
    SpatialFrames::feature defaultFrame : DefaultFrameLife[1]
      Above are domain Anything ("top level").
      Must be const to prevent deleting the (single) *Life, then
        immediate recreating and "resetting" feature (logically
        possible). 

  Readonly features on occurrence classes:
    Are these intended to be features only of lives?

    Transfers::Transfer:isInstant/isMove/isPush: Boolean[1]
    StatePerformances::StatePerformance:incomingTransitionTrigger : MessageTransfer [0..1] default null


"Root, top-level" features on non-occurrence classes
  All intended to "change" over time when specialized to occurrence classes.

  Base::things: Anything [1..*] nonunique
  Base::dataValues: DataValue[0..*] nonunique subsets things
  Base::naturals: ScalarValues::Natural[0..*] subsets dataValues
  
  //Can these change dynamically?  
  Base::zeroOrOne [0..1]  (multiplicity)
  Base::oneToMany [1..*]  (multiplicity)
  Base::zeroToMany [0..*] (multiplicity)

  Links::links: Link[0..*] nonunique subsets things
  Links::binaryLinks: BinaryLink[0..*] nonunique subsets links
  Links::selfLinks: SelfLink[0..*] nonunique subsets binaryLinks

  //Can these change dynamically?  
  Metaobjects::feature metaobjects : Metaobject[0..*] :> objects

  Occurrences::occurrences: Occurrence[0..*] nonunique subsets things;
  Occurrences::earlierFirstIncomingTransferSort : IncomingTransferSort 

  Objects::objects: Object[0..*] nonunique subsets occurrences {
  Objects::linkObjects: LinkObject[0..*] nonunique subsets links, objects intersects links, objects {
  Objects::binaryLinkObjects: BinaryLinkObject[0..*] nonunique subsets binaryLinks, linkObjects

  Performances::, Transfers:: top-level features, all for steps,
    exprs, transfers, flows.  I figure these are non-vars (at least
    for steps, transfers, and flows, since their specializations will
    be linked by successions).

Other features on non-occurrence classes that should be vars when
specialized to occurrences
  
  Not
    Base::Anything::self: Anything[1] subsets things chains things.that
    Base::things::that : Anything[1]
    Links::*

Other features on occurrence classes that should be vars
    Features specializing vars above must be vars (omitted here).

    Clocks::Clock::currentTime:NumericalValue[1]

    Occurrences::Occurrence::suboccurrence
      Root for composition semantics.

    Occurrences::Occurrence:: (purely) Space relations between occurrences
      These'll typically change over time, tho they can also relate things
        happening at separate times (ie, aren't always time-aligned).


    ??  (Might be const)
      Occurrences::incomingTransfersToSelf subsets incomingTransfers {
      Occurrences::Occurrence::outgoingTransfersFromSelf subsets outgoingTransfers        
      Occurrences::Occurrence::incomingTransferSort
      Occurrences::Occurrence::isDispatch : Boolean[1] default false
      Occurrences::Occurrence::dispatchScope: Occurrence [1] default self;
      Occurrences::Occurrence::runToCompletionScope: Occurrence [1] default self;    

    Objects::Object::involvingPerformances: Performance[0..*] subsets performances 
      (specialized by enactedPerformances)
      Steps, but only bc they're typed by performances.  Linkable by successions?

    LinkObjects    

    ??
      "Root" Performances::Performance

    Not
      Clocks::Clock::timeFlowConstraint
        Already written against snapshots (simpler as var)
      Occurrences::Occurrence::Time relations between occurrences
        Intended for the entire time of the occurrence
      Observation::*
      SpatialFrames::*
        
    ??
      SemanticMetadata::baseType : Type[1]
      Occurrences::Occurrence::localClock:Clock[1] default universalClock
        Should snapshot always use the clock of their life?  If not, I
        guess this could be a var.
      Occurrences::Occurrence:incoming/outgoingTransfersTo/FromSelf