What would you call a fact that is inserted once and the conflict set computed (the rules that can fire). The fact is then retracted so no more matches can take place, but the conflict set itself is allowed to fire (assuming their other facts remain true). I think this is quite a common use case and most users will handle this via a lower salience and retracting the fact manually, but I think it's useful enough to build in as a keyword on type declaration. We just need a name for it :) Mark