Ravi discovered a hole in the traversal semantics we use in the presence of intersection
in the strategies. Intersection is implemented in DAJ and is a central feature of DAJ.
We basically use intersection to eliminate undesired nodes and edges in a modular way.

Remember the Mitch-semantics for traversals: Traverse that edge if P holds: 
Does there exist an object containing a path satisfying the strategy? 

Ravi's important observation is that in the presence of intersection P becomes NP-complete.
http://koods1.ccs.neu.edu/traversal-wiki/index.php/SatisfiabilityHardness

(password K@rl)

See:
pages 42 and up in:

-rw-r--r--   1 lieber   faculty   141096 Jul 16 14:53 intersection+negation1.pdf
-rw-r--r--   1 lieber   faculty   259584 Jul 16 14:51 intersection+negation1.ppt

/proj/adaptive/www/design-decisions/traversal-strategies/intersection>

for a discussion and possible solutions.

How would you resolve this?

-- Karl