Life In 19x19

New remarkable ko beast?
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Author:  jann [ Thu Apr 21, 2022 1:09 am ]
Post subject:  Re: New remarkable ko beast?

Criado wrote:
... This is because adding a * (a dame) will change the outcome of the game at higher temperatures
... Since * has mast value 0, then it should be the case that m(G)+m(*)+t/2 = m(G)+t/2.
... in general that for any t>0, the thermograph of G should coincide with that of G+*.

As I said I'm not sure if I follow the CGT part. To get this no-pass-go behavior (where dame may change things) you need a somewhat no-pass ruleset. This means strict superko (where pass lift no ban), which basically excludes Asian CJK rules and means AGA/NZ only. But AGA uses area scoring, where a dame is valuable. Is it still a * then? And (while moves into territory do matter in that case), how does adding a dame change the outcome if the side who can first capture the ko will only do that after filling all dame? (cf. molasses ko under PSK - another known no-pass-go case - where such postpone is not possible)

From a rules view, 1-eye-flaw is only problem for strict superko, since all it shows is the importance of passes as whole / fully functional moves. Otoh 0-sided kos can be challenging even with complete passes, as a repetition that needs to be recognized despite spanning stops - while at the same time similar repetition with a double ko seki (without score changes) should not.

I'm not sure how can the CGT view handle (if at all) 0-sided kos under normal, everyday rules where passes do lift bans. But in this case (if the score is otherwise close enough) moves into the position gain nothing regardless of temperature, since the outcome is still draw on repetition even if I omit or postpone my next capture (the opponent can do nothing to prevent that later with or without resumption).

Author:  jann [ Fri May 13, 2022 8:01 pm ]
Post subject:  Re: New remarkable ko beast?

Your original post was just bumped by dhu163, and it seems to shed some light on the logical problem:

Criado wrote:
positional super ko (the standard in CGT) ... Recall that in this context, passing does not lift ko bans but playing an environment play does.

This doesn't seem like a reasonable start. In particular, environmental plays seem hard to use correctly in relation to a superko game - assuming the environment is supposed to offer a finely granulated transition from more valuable plays/coupons down to zero.

Under strict superko (where they don't lift bans), "passes" are not the same infinite, zero-valued but otherwise fully functional, environmental-coupon-compatible moves as in modern go (where they do lift bans, except for AGA/NZ). And an environmental stack cannot form a continuous bridge from high-valued ban-lifting moves down to near-zero-valued NON-ban-lifting move.

(Bill's idea / workaround rule for how to allow passes to lift superko ban may also be relevant here, but it has its own problems and also doesn't seem to solve 0-sided kos.)

Author:  luigi [ Sat Sep 30, 2023 10:50 am ]
Post subject:  Re: New remarkable ko beast?

Is it the case that, in No-Pass Go with prisoner return, if there are no situations that invite repetitions, the winner in this position is simply the player with the greater sum of territory and prisoners, with the provisions that the ko intersection be counted as territory for the opponent and half a point be subtracted from the player to move?

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