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How do you call a position for which you have MGOTE > MB,SENTE, MW,SENTE ? Is it a seki or could this position be also something else?RobertJasiek wrote:To calculate values of a player's option, temporarily prune the tree by removing the currently not considered alternative option. This leaves two options for the opponent's start.
Your tree has options for both starting players and this makes it more complicated than any of my theory uses explicitly. Nevertheless, your questions are valid for a possibly broader understanding.
With two options for the opponent's start remaining in the pruned tree, CGT techniques must be considered. In particular, we try to detect if any of the opponent's options is dominated or reversible so can also be pruned.
If thereby the tree is without alternative options, calculate the tentative gote move value, Black's tentative sente move value (for the left sente sequence) and White's tentative sente move value (for the right sente sequence) like we always calculate gote or sente move values, respectively.
If, however, two options of the opponent remain and other reasoning cannot choose clearly, then tentative move values are undefined (so far).
If all tentative move values, tentative counts and Black's and White's follow-up move values could be calculated for a particular option, we derive the assessments of the type of the initial position for that option.
"Definitions 17 [types]
For such a local endgame, we define these types:
local gote :<=> MGOTE < MB,SENTE, MW,SENTE,
Black's local sente :<=> MW,SENTE ≥ MGOTE > MB,SENTE,
White's local sente :<=> MB,SENTE ≥ MGOTE > MW,SENTE,
Black's ambiguous :<=> MW,SENTE > MGOTE = MB,SENTE,
White's ambiguous :<=> MB,SENTE > MGOTE = MW,SENTE,
doubly ambiguous :<=> MGOTE = MB,SENTE = MW,SENTE." [22]
Again, I do NOT define the types of individual moves. I define the types of positions.
https://www.lifein19x19.com/viewtopic.p ... 45#p143245
As previously discussed, local double sente does not exist so seki is the most prominent candidate type of positions but others might exist. Maybe two-sided ko threat regions, maybe something else.Gérard TAILLE wrote:How do you call a position for which you have MGOTE > MB,SENTE, MW,SENTE ? Is it a seki or could this position be also something else?
BTW did you define a seki position?
In my post https://lifein19x19.com/viewtopic.php?p=280605#p280605 I used MGOTE as M_GOTE_OF_SENTE_OPTIONS and your answer was simply:RobertJasiek wrote: "M_GOTE > M_B,SENTE, M_W,SENTE"
where these are the tentative values of a local endgame with both players' follow-ups. Needless to say, _B uses Black's sente sequence and _W uses White's sente sequence, where sente sequence is an alternating sequence of even length. Adapting this to a local endgame with gote and sente options is straigtforward. Note that then the M_GOTE in the definition does not belong to the alternative gote options but still belongs to the sente options, that is, it is M_GOTE_OF_SENTE_OPTIONS.
That is quite disturbing indeed. Does it depend on whether your are in early endgame or last endgame? What is the rule to understand what you mean by using simply MGOTE. In this difficult area where we are dealing with gote and sente options guessing what means MGOTE depending of the context is the best way for misunderstanding.RobertJasiek wrote:Distinguish MGOTE_GOTE_OPTION from MGOTE_SENTE_OPTION!
RobertJasiek wrote:For identifying a "sente" option, we need its internal MGOTE. Once all the details are identified, the theorems only need the MGOTE of the gote option (or / and maybe the MSENTE of the sente side).
I am not sure that your way of identifying a sente option corresponds to the common understanding of a sente option for a go player.RobertJasiek wrote:For identifying a "sente" option, we need its internal MGOTE. Once all the details are identified, the theorems only need the MGOTE of the gote option (or / and maybe the MSENTE of the sente side).
Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.Gérard TAILLE wrote:
According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.
OK Robert, in that case let's take a small modification of your example (EDIT):RobertJasiek wrote:Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.Gérard TAILLE wrote:
According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.
a and b are dominated by c. (From a go player's understanding. I have not verified it by CGT.) Therefore, we ignore a and b. Thus it is immaterial whether a or b are identified as sente options.
Maybe you did not see my edit modification: instead of starting from your position (with ko) I started from Dany's position. Sorry for that Robert.RobertJasiek wrote:Black's ambiguous.
Indeed! This I analysed:Gérard TAILLE wrote:Maybe you did not see my edit modification
More generaly, assume a move "a" cannot be better than a move "c" (whatever an environmment made of gote areas without follow-ups). Do you agree to call such move a bad move? My view is to avoid calling it a sente option because it is against the common understanding of a sente option. IOW I would like to reserve the wording sente option only to options that could be the best option in a certain environmment made of gote areas without followo-ups.RobertJasiek wrote:Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.Gérard TAILLE wrote:
According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.
a and b are dominated by c. (From a go player's understanding. I have not verified it by CGT.) Therefore, we ignore a and b. Thus it is immaterial whether a or b are identified as sente options.
is sente Black has very little choice and the expected sequence is the following:No Robert I never assumed "a" is sente. I only claimed that black is ALLOWED to choose to answer "a" by the sequence shown which is sente for white. OC black may choose other options (including tenuki) and that is the reason why white "a" is not the best move.RobertJasiek wrote:You guess A is sente but we do not know if it is.