methinks the very hard puzzles that are soluable with Pappocom's valid logic set must be a little less than infinite.
I'd be very interested to know how many that is but another thread suggests its not simple to answer.

clara5218 wrote:hi davidpbrown, plse forgive me, im new at this game, but are you sure your pencil marks are correct in your grid? i see a 4 can be pencilled in at row 6 column 5 you only list 6,8 but i cant see why you cannot pencil in a four? is it because there are pencil marks for 4 in the r5c6 and r6c6? please explain why 4 should not be pencilled in at r6c5 - please dont see this as a criticism i am just trying to understand the rules of putting in pencil marks - cheers