Create node B and draw a link from node A to node B
Edit node B's potential. Make it a Tree/ADD. It have a single leaf by default, including the whole range of A's domain (by default (-infinity, +infinity)).
Reduce node A's domain to [0,+infinity).
Go back to B's potential and see that the Tree/ADD's leaf range has not changed.
The implementation should be made very carefully, as the reduction of the domain could even make some TreeADD interval disappear. For example, let us suppose that a TreeADD have three intervals: (-infinity, -1), [-1,1] and (1,infinity), and then the user decides to reduce the domain to (0,infinity).
Francisco J. Diez
Certainly, in some cases when the domain changes some branches should be pruned. In contrast, increasing the upper limit of the domain should lead to an increase of the upper limit of the corresponding branch instead of adding a new branch.