2009/4/14 Brian Sheppard <[email protected]>: > But in game 739216 the stones are the same, but the other color is moving. > That can't be a repetition...
Well, that's what distinguishes _positional_ superko from _situational_ superko. See <http://senseis.xmp.net/?Superko> . As Jason House wrote, > That sounds like a classic _positional_ super ko violation. Any board > repetition is a ko violation, regardless of the player to play. _Regardless_ of the player to play. [Emphasis mine.] Now, one might have _philosophical_ disagreement about whether that's the way a server "should" implement a prohibition on cycles, or about whether that's "what the framers intended". And I might even agree with you that _situational_ superko is "superior" in that regard. Under situational superko, your example, as you say, _can't_ be a repitition. [So, one might well ask, what is the reason for prohibiting it?] But whether we like it or not, that is how the server authors have chosen to implement the prohibition (even though allowing the _other_ player to play in the position would not really create a _cycle_, in the sense of a "directed acyclic graph"). [See <http://en.wikipedia.org/wiki/Directed_acyclic_graph>.] Situational superko can be defined in terms of not permitting a cycle in the game-tree, thus always preserving its acyclic nature. [Positional superko, IMHO, has no such elegant rationale.] But postional superko is what both KGS and CGOS implement, and we have to live with that, at least until they see the light. -- Rich _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
