Pinch-outs can be thought of as a single horizon that splits into a double horizon. If the reference trace for flattening goes through the single horizon, then the shifts from the flattening process should collapse the double horizon into one and therefore the solution is non-unique. On the other hand, if the reference trace goes through the double horizon, then the flattening process should result in replicating or stretching the single horizon into two.

7/8/2003