visualizing valid and invalid go states

[skydyr]

Depending on the ruleset, there is also a state where one side can play on an intersection, but the other side cannot because they would commit suicide, either for the stone played or for that stone and an attached group that was in atari.

[dohduhdah]

Depending on the ruleset, there is also a state where one side can play on an intersection, but the other side cannot because they would commit suicide, either for the stone played or for that stone and an attached group that was in atari.

As far as I know, the ruleset doesn't make any difference regarding the number of positions KGS lets you set up when you edit a custom game.

[skydyr]

Depending on the ruleset, there is also a state where one side can play on an intersection, but the other side cannot because they would commit suicide, either for the stone played or for that stone and an attached group that was in atari.

As far as I know, the ruleset doesn't make any difference regarding the number of positions kgs lets you set up when you edit a custom game.

It allows suicide under NZ rules but not the other rulesets. If you start from an arbitrary board position, are you concerned with whether or not anyone is able to play on a particular empty intersection legally? I mean apart from ko, which you said you did not care about because it depended on the order of previous moves, as I recall.

[dohduhdah]

It allows suicide under NZ rules but not the other rulesets. If you start from an arbitrary board position, are you concerned with whether or not anyone is able to play on a particular empty intersection legally? I mean apart from ko, which you said you did not care about because it depended on the order of previous moves, as I recall.

I'm not concerned with moves at all. I'm concerned with states (a given position, like the way KGS lets
you set up a position in terms of stones on the goban, where all stones and chains have at least 1 liberty).
Moves are combinations of two states, so that's really irrelevant for the discussion regarding individual
states that are categorically valid or invalid.

[hyperpape]

Seriously, it's clear what the OP was interested in, and whether or not state is the right way to describe it, let's not waste our time on a dumb terminalogical point.

[Mike Novack]

I think there is a terminology problem. And yes, I did understand the original purpose.

Let me try to make it a bit clearer?

Of course for just determining if a particular arrangement of stones on the board is possible (legal) one can speak of "the state of the board". But what I am saying is that a particular arrangement of stones on the board might be more than one statefor the purposes of the game of go.

Let me try to put it another way. Doduhdah, are you not intending to be able to determine if given a state (the way you want to define it) can be transitioned into some other state? << by adding a stone; aka, making a move >> In other words, after you have determined "this is a legal state" being unable to determine what states would be possible subsequent states?

[dohduhdah]

I think there is a terminology problem. And yes, I did understand the original purpose.

Let me try to make it a bit clearer?

Of course for just determining if a particular arrangement of stones on the board is possible (legal) one can speak of "the state of the board". But what I am saying is that a particular arrangement of stones on the board might be more than one statefor the purposes of the game of go.

Let me try to put it another way. Doduhdah, are you not intending to be able to determine if given a state (the way you want to define it) can be transitioned into some other state? << by adding a stone; aka, making a move >> In other words, after you have determined "this is a legal state" being unable to determine what states would be possible subsequent states?

Sorry for the confusion. In the context of this discussion regarding the visualization of valid and
invalid states, I'm only interested in individual states and not in sequences of states (like a move,
which is a sequence of two states).

The number of valid states for a 3x3 goban is 12675 and that's exactly the number of positions KGS will
let you set up when you edit a custom game, as opposed to the 7008 states KGS will not let
you set up on a 3x3 goban, because they involve at least one stone or chain that lacks liberties.

So for this notion of validity that is only concerned with individual states, the only aspect that is relevant
is whether or not all chains/stones on the goban have at least one liberty.

[hyperpape]

Stop using the word "state"! Both of you! You're killing me.

[xed_over]

Stop using the word "state"! Both of you! You're killing me.

instead, they could use: condition, shape, situation, circumstances, position, predicament, plight

[dohduhdah]

Stop using the word "state"! Both of you! You're killing me.

Somehow I feel that 'valid state' seems more appropriate than 'legal position'.


I thought state space was a fairly universally accepted concept.

http://en.wikipedia.org/wiki/State_space

"In games, the state space is the set of all possible configurations within the game."

[xed_over]

And this would be neither a valid state nor a legal position nor possible configuration.

$$
$$+---+
$$|.XO|
$$|..X|
$$|...|
$$+---+

Click Here To Show Diagram Code

[go]$$
$$+---+
$$|.XO|
$$|..X|
$$|...|
$$+---+[/go]

[dohduhdah]

And this would be neither a valid state nor a legal position nor possible configuration.

$$
$$+---+
$$|.XO|
$$|..X|
$$|...|
$$+---+

Click Here To Show Diagram Code

[go]$$
$$+---+
$$|.XO|
$$|..X|
$$|...|
$$+---+[/go]

Yes, one of the 7008 possible invalid states on a 3x3 goban.

[Bonobo]

Wbt the word “constellation”, as this is not only about position but about position of stones in relation to other stones’ positions.

Grtz, Tom

[hyperpape]

I actually tend to use state the way Mike does, and I think that's more common in abstract discussions of the game, rules, etc.

[Mike Novack]

Question:

Assuming the original definition of legal state (all groups have at least one liberty) there is a question of "reachable" states. Take this example:

$$
$$+---+
$$|X.O|
$$|XX.|
$$|.X.|
$$+---+

Click Here To Show Diagram Code

[go]$$
$$+---+
$$|X.O|
$$|XX.|
$$|.X.|
$$+---+[/go]

[/quote]

In go, black and white stones are placed alternately and once placed, not moved unless removed by capture. Only one white stone could have been captured (the number of black stones placed on the board can never be less than the number of white stones placed) so there are too few white stones present in the diagram.

So that would be a legal state but not a reachable legal state?