I’m not sure what you are getting wrong. My initial inclination was to think as you do. But then I thought of this:
You are probably imagining N to be the number of moves deep that need to be searched. Which you probably think is roughly the square of the board size (nominally, 19). The trouble is, what N really means is the size of the specific problem instance. So, it is possible to imagine Go problems on 1001x1001 boards where the number of stones already played is small. I.e. N is much less than a million, but the amount of computation needed to search the tree is on the order of 1000000^1000000.
ETA: This explanation is wrong. Darius got it right.
Much appreciated! I was taking N to be the number of squares on the board. My current thought is that, as you said, the number of possible move sequences on an N square board is of the order of N^N (actually, I think slightly smaller: N!). As you said, N may be much larger than the number of stones already played.
My current understanding is that board size if fixed for any given Go problem. Is that true or false? If it is true, then I’d think that the factor of N branching at each step in the tree of moves is just what gets swept into the nondeterministic part of NP.
I’m not sure what you are getting wrong. My initial inclination was to think as you do. But then I thought of this:
You are probably imagining N to be the number of moves deep that need to be searched. Which you probably think is roughly the square of the board size (nominally, 19). The trouble is, what N really means is the size of the specific problem instance. So, it is possible to imagine Go problems on 1001x1001 boards where the number of stones already played is small. I.e. N is much less than a million, but the amount of computation needed to search the tree is on the order of 1000000^1000000.
ETA: This explanation is wrong. Darius got it right.
Much appreciated! I was taking N to be the number of squares on the board. My current thought is that, as you said, the number of possible move sequences on an N square board is of the order of N^N (actually, I think slightly smaller: N!). As you said, N may be much larger than the number of stones already played.
My current understanding is that board size if fixed for any given Go problem. Is that true or false? If it is true, then I’d think that the factor of N branching at each step in the tree of moves is just what gets swept into the nondeterministic part of NP.