parid0056 | Wed, 22 Jan 2003 06:28:02
In all instances of each type of arc, the significance of a node's service as one of the endpoints is different from the significance of a node's service as the other endpoint. Given two nodes, N1 and N2, there are eight possible forms of connectedness between them, since there are four types of arcs. They are enumerated in the following subclauses.
Nodes may serve as either endpoint of each of the four types of arcs enumerated in 3.3.1. The relationship between the nodes serving as endpoints of any arc is symmetric, that is an AT arc is also a TA arc. Service by a node as the one of endpoints of an arc determines (in part) its situation in topic map space. All of endpoints of any arcs served by a node collectively determine the node's situation and not its service in a particular types of arc (if any). (insert reference to revised parid0076 (see below) here)
Restatement that does not require the remaining subsections of this section.