Permanence
There are different types of permanence that are recognized in this documentation with the $permanenceType notation.
$switch
Like an on an off switch.  If an actor never changes the switch position, it might remain in that state $permanently.
$lasting
An actor can have a $lasting impression.
$interval
A specific amount of time passing.  Most $single actions also have <interval> permanence, because it is known how much time passed before the pervious action and the next action.
$repeating
A repeated $interval that is $semi-permanent.
$wave
A back and forth variation that is usually just $lasting> and rarely $semi-permanent.
$single
Permanence that lasts within the time period of a single line of communication.  This is the default permanence unless otherwise specified.
$block
Permanence that lasts within the time period of a groups single line communication.  This might be denoted with a [] to mark the block.
$iteration
If a conversation feels completed, and a new conversation is started... that could be considered an $iteration.
$permanent
Permanent is rare as everything changes.