--- In aima-talk@yahoogroups.com, "kiana" <blacksilk79@...> wrote:
>
> I understand the material in the chapter. However, the exercises
are
> completely confusing to me. Therefore, a discussion of the chapter
may
> clarify. For the 8-puzzle problem, I am not able to understand the
> existence of two disjoint sets of all possible states in which a
state
> from one set can't transform to a state in the other set by any
number
> of moves. I would assume any state can be reached by in other
state. In
> other words, there are situations (initial state - goal
configuration)
> in which the puzzle isn't solvable? Does the two disjoint sets exit
> because the problem becomes an NP-Complete problem for those states
> trying to reach the states in the other disjoint set. And, the 9!/2
> calculation for all possible states derives from this theorem of
> exactly half of the possible states transform into a given goal, is
> this true?
>
I'm confused, any clarification is greatly appreciated.