Flash MX 2004.
halfEdge.getOppositeHalfEdge()
None.
A HalfEdge object.
Method; gets the HalfEdge object on the other side of the edge.
The following example stores the half edge opposite hEdge in the otherHalfEdge variable:
var shape = fl.getDocumentDOM().selection[0];
var hEdge = shape.edges[0].getHalfEdge(0);
var otherHalfEdge = hEdge.getOppositeHalfEdge();