Moment

In the nodal model a moment is an instance of generic organisation which exists and undergoes change for a period of time. A moment is a nodally reducable structure which includes associations representing the generic organisational concepts.

Duality

The moment concept encapsulates the subject/object dichotomy by having two child concepts, one representing the context, subject or container aspect and another for the children, the objects under investigation/manipulation. Note that there doesn't actually need to be an association for the container apsect, but there does need to be one for the children.