Very nice, I was merely considering single letters.
minimac may master the next game if he wishes.
The empty koan is customarily disallowed. Having some interest in set theory, disallowing the empty koan feels unnatural, but the offline game has a practical reason for it: The marked empty koan looks like a stray marking stone on the table.
Nonetheless, rules could always be evaluated for the empty koan. "The first letter has property E" evaluated for the empty koan, is false for any formula E. "All letters have property E" is true.
-- Simon
