Cards or app for miai-value based endgame practice?

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kvasir
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Re: Cards or app for miai-value based endgame practice?

Post by kvasir »

Gérard TAILLE wrote:OK let's take two examples (the first is a gote situation, the second a a (reverse) sente situation
Your example was confusing to me for the reason that it appears that it sometimes won't work unless C = 0 and all the values are positive. I think I know what you mean, it's the following kind of thing. I'm not sure why you suspect there is a counter example :study:

Code: Select all

                  A
               /     \
              /       \
             B         C
            / \       / \
           /   \     /   \
          D     E   F     G

T(A) = min(E - C, (E - C) / 2 + T(B) / 2) 
     = min(B - F, (B - F) / 2 + T(C) / 2)
     = min(D - C, (D - C) / 2 - T(B) / 2)
     = ... and so on
(Black moves go to left with positive numbers and white moves go to right with negative numbers.)

This basically follows the pattern that the move value is the minimum of the value assuming sente and the value assuming gote.

We can write
E + T(B) - T(A) = C + T(A)
T(A) = (E - C) / 2 + T(B) / 2
for gote moves and
E = C + T(A)
T(A) = E - C
for sente moves. These are relationships that can be read directly from the game tree above. Now, when a player makes a move it's the other player's choice if to defend in gote or allow the follow up. That is, it's up to the other player if we get the sente or gote case. It follows that the move value is the lesser of the gote and sente since it is the second player's choice and the lesser is the better choice for that player.

Btw if it was not clear why (E - C) / 2 + T(B) / 2 is the gote move value then to see this note that
B = E + T(B)
and therefore
(B - C) / 2 = (E + T(B) - C) / 2 = (E - C) / 2 + T(B) / 2

The first time I heard about this was about 10-15 years ago, a Japanese friend was taking some lessons from a Japanese professional player who thought him something like this, not as pseudo mathematics though, at least this where he said he had this knowledge from.

Hope I didn't make too many typos and thinkos.
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

kvasir, such algebra is a means to study these aspects indeed. You write T for local temperature, which is our simple games is the move value.
min(D - C, (D - C) / 2 - T(B) / 2)
Here I am lost.
for sente moves
For Black's sente moves! :)
We can write
We can for simple local endgames with settled D, E, F, G.

For Gerard's partially more general case, we can start with the assumption of no kos. For the general left subtree D, long alternating traveral sequences starting from the initial position A do not occur. However, when assuming known T(D), short or long alternating traveral sequences starting from D can occur (without kos by assumption), or at D Black's correct move might be a pass. I have not reflected (yet) whether the subtree might have to be studied or the mere assumption of known T(D) is sufficient but this is what you need to study, Gerard.

CGT reversal alone cannot simplify the subtree in general. The method of "comparing the opponent's branches" is another candidate to possibly simplify the subtree. However, even such a method a) considers the left alternating follower X of D and b) compares E >= E'', where E and E'' are the positions and E'' is the position two alternating moves succeeding E.

Therefore, I do not think that you can just write '?' for the children of D but you need to assess at least X, E and E'', unless you come up with yet other general tree simplification methods.
The first time I heard about
Some such techniques have been known subconsciously by a few users of traditional endgame theory but I have never seen them described explicitly. In particular, Richard Bozulich has applied something like this for three problems but I had to infer his doing and the presumed value manipulation technique by myself, which I only could because I had already done algebra of your type (the type of adding / subtracting [half] a gote move value to travel to / from a grandchild).
Gérard TAILLE
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

Code: Select all


               A                            A
              / \                         /   \
             /   \                       /     \
            B     C                     B       C
           / \                         / \     / \
          /   \                       /   \   /   \
         ?     E                     D     E F     G
         My proposal                 Kvasir proposal
Oops, changing tree may lead to completely different conclusion. To understand what I mean let's take another very different tree:

Code: Select all

               A
              / \
             /   \
            B     C
           / \ 
          /   \
         D     ?
With this tree even if you know the count of c and d of positions C and D and the miai value vb of B you cannot deduce the miai value of A as proved by the two following examples with c = 0, d = 12 and vb = 5:

Code: Select all


               A                           A
              / \                         / \
             /   \                       /   \
            B     0                     B     0
           / \                         / \ 
          /   \                       /   \
         12    E                     12    E
              / \                         / \
             /   \                       /   \
            6    -2                     4     0
           va = 3                       va = 2
To answer my question you are only allowed to build a subtree of node D, nothing else.

Note : I agree with Kvasir showing that a "min" rather than a "max" has to be used. Thank you for your help.
RobertJasiek wrote: For Gerard's partially more general case, we can start with the assumption of no kos. For the general left subtree D, long alternating traveral sequences starting from the initial position A do not occur.
Yes Robert long alternating traveral sequences starting from the initial position A cannot occur. That is a key point of my tree proposal.
RobertJasiek wrote: CGT reversal alone cannot simplify the subtree in general. The method of "comparing the opponent's branches" is another candidate to possibly simplify the subtree. However, even such a method a) considers the left alternating follower X of D and b) compares E >= E'', where E and E'' are the positions and E'' is the position two alternating moves succeeding E.
I do not understand what you mean Robert because for me E is assumed to be a leaf.
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

I spoke about E in a more general context but are fine with your different study scope of settled E. However, settled E has the consequence that we cannot apply the method of comparing the opponent's branches to possibly simplify the subtree of D. By setting E settled, you are not necessarily easing your task (yet) because this way of simplifcation is unavailable:)
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

RobertJasiek wrote:I spoke about E in a more general context but are fine with your different study scope of settled E. However, settled E has the consequence that we cannot apply the method of comparing the opponent's branches to possibly simplify the subtree of D. By setting E settled, you are not necessarily easing your task (yet) because this way of simplifcation is unavailable:)
Let's try this reasonning:

Code: Select all

               A
              / \
             /   \
            B     C
           / \ 
          /   \
         ?     E
if va < vb then black AB move is sente and white have to answer with BE => va = e (e - c with c = 0)
if va > vb then:
White to play => white plays AC and black play in the environment => score1 = 0 + t = t
Black to play => black plays AB gote and white plays in the environment. Then, when temperature of the environment drops to vb, because vb is the miai value of B we can assume that white will play BE and black will play in the environment to gain vb points => score2 = -t + vb + e
you can now calculate va:
score1 = score2 => t = -t + vb + e => 2t = (vb + e) / 2
and va = vb/2 + e/2

Eventually you can conclude that va = min (e, e/2 + vb/2)

With this reasonning I do not mind if a ko exist in the subtree of B. I only assume that the environment is ideal.
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Re: Cards or app for miai-value based endgame practice?

Post by kvasir »

Gérard TAILLE wrote:

Code: Select all


               A                            A
              / \                         /   \
             /   \                       /     \
            B     C                     B       C
           / \                         / \     / \
          /   \                       /   \   /   \
         ?     E                     D     E F     G
         My proposal                 Kvasir proposal
Oops, changing tree may lead to completely different conclusion. To understand what I mean let's take another very different tree:
I will amend as follows to be clearer.

Code: Select all

                  A
               /     \
              /       \
             B         C
            / \       / \
           /   \     /   \
          D     E   F     G

va = min(E - C, (E - C) / 2 + vb / 2)
   = min(B - F, (B - F) / 2 + vc / 2)
   = min(D - C, (D - C) / 2 - vb / 2)
   = min(B - G, (B - G) / 2 - vc / 2)
You can derive all of these formulas by writing down relationships between the nodes.

For example for D and C. It's possible to do this in different ways but if you start with these three relationships

D - vb = B
B - va = A
A = va + C

Which are true when we talk about the gote (unforced play) case, they are not true if play is forced in these nodes.

It is fairly easy to go from this to
D - vb - va = va + C
at which point solve for va
va = (D - C) / 2 - vb / 2
The right side of which is the gote case in the "min" function of the third formula.


These two cases were shown
Gérard TAILLE wrote:

Code: Select all


               A                           A
              / \                         / \
             /   \                       /   \
            B     0                     B     0
           / \                         / \ 
          /   \                       /   \
         12    E                     12    E
              / \                         / \
             /   \                       /   \
            6    -2                     4     0
           va = 3                       va = 2
Here we need the correct value of vb to proceed to calculate va, if we have the correct value there is no problem.


First case:

Code: Select all

               A     
              / \     
             /   \   
            B     0  
           / \       
          /   \      
         12    E     
              / \    
             /   \    
            6    -2 
Here we must be careful to work with the right temperature in the subtrees, here vb = 6 and ve = 8 since play is forced at lower temperatures. Now marking paths with * that are excluded for the reason that the other player's move is forced, we have this tree.

Code: Select all

         position values             move values
               3                           2
              / \                         / \
             /   \                       /   \
            2     0                     6     .
           * \                         * \
          *   \                       *   \
         12    6                     .     8
              / *                         / *
             /   *                       /   *
            6    -2                     .     .
Using D = 12, C = 0, vb = 6, we can apply the formula

va = min(D - C, (D - C) / 2 - vb / 2)
= min(12 - 0, (12 - 0) / 2 - 6 / 2)
= min(12, 6 - 3) = 3


Consider the subtree

Code: Select all

            B   
           * \    
          *   \     
         12    E     
              / *    
             /   *    
            6    -2
If we make the error to not realize that play is forced then we get incorrect values, that is values that could be correct if this was not a follow up from a lower temperature position.

Code: Select all

         position values             move values
            5                           9     
           / \                         / \
          /   \                       /   \
         12    2                     .     4
              / \                         / \
             /   \                       /   \
            6    -2                     .     .
Using B = 12, F = 6, vc = 4, we can apply the formula

va = min(B - F, (B - F) / 2 + vc / 2)
= min(12 - 6, (12 - 6) / 2 + 4 / 2)
= min(6, 3 + 2) = 5

or using B = 12, G = -2, vc = 4, we can apply the other formula

va = min(B - G, (B - G) / 2 + vc / 2)
= min(12 - (-2), (12 - (-2)) / 2 - 4 / 2)
= min(14, 7 - 2) = 5

If we go ahead to use this value in the previous case we get an incorrect result

Using D = 12, C = 0, vb = 5 (wrong!!), we can apply the formula

va = min(D - C, (D - C) / 2 - vb / 2)
= min(12 - 0, (12 - 0) / 2 - 5 / 2)
= min(12, 6 - 2.5) = 3.5

which is not the solution.


Second case:

Code: Select all

              A
             / \
            /   \
           B     0
          / \
         /   \
        12    E
             / \
            /   \
           4     0
Here too we must consider that play is forced at low temperature.

Code: Select all

         position values             move values
               2                           2
              / \                         / \
             /   \                       /   \
            4     0                     8     0
           * \                         * \
          *   \                       *   \
         12    4                     .     4
              / *                         / *
             /   *                       /   *
            4     0                     .     .
Using D = 12, C = 0, vb = 8, we can apply the formula

va = min(D - C, (D - C) / 2 - vb / 2)
= min(12 - 0, (12 - 0) / 2 - 8 / 2)
= min(12, 6 - 4) = 2



In this case there is something interesting, if we assume the following tree instead, we get a "correct" value (at least given how I filled in the tree at the top level) but it's not the value that I think we want.

Code: Select all

         position values             move values
               1                           2
              / \                         / \
             /   \                       /   \
            2     0                     10    0
           * \                         * \
          *   \                       *   \
         12    2                     .     2
              / \                         / \
             /   \                       /   \
            4     0                     .     .
Using D = 12, C = 0, vb = 10, we can apply the formula

va = min(D - C, (D - C) / 2 - vb / 2)
= min(12 - 0, (12 - 0) / 2 - 10 / 2)
= min(12, 6 - 5) = 1

Here we botched the calculation (again?). The error is that the first tree is better for black and black can force the result, that is black will play in gote as shown in the first tree.

Conclusion
I think this must work. You need to use the correct values for the position values and move values, that is you need to somehow have the right idea of which moves are forced and which are not. That means if you have two continuations that you can estimate the position value and can recall (or guess) a move value for the third hard to fathom continuation you can try to make a good estimate without working through the difficult continuation.
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

kvasir wrote:
Gérard TAILLE wrote:

Code: Select all


               A
              / \
             /   \
            B     C
           / \ 
          /   \
         ?     E
 My proposal : va = min(e, e/2 + vb/2)   


Two other(different) examples
               A                           A
              / \                         / \
             /   \                       /   \
            B     0                     B     0
           / \                         / \ 
          /   \                       /   \
         12    E                     12    E
              / \                         / \
             /   \                       /   \
            6    -2                     4     0
           va = 3                       va = 2
Here we need the correct value of vb to proceed to calculate va, if we have the correct value there is no problem.
At least, seeing your post, it is obvious that we have the same understanding: applying similar formula to the two different examples above lead to difficulties due to gote-sente relationship.
From that point we have indeed two different approaches:
1) my approach is to identify on which kind of positions the formula can be easily applied, hoping that in practice, a majority of encountered positions are concerned
2) you approach seems (?) to adapt the miai value definition in such a way that the formula applies to (almost?) all kind of position.

General comment : if I understand correctly the theory the miai value is defined for a position ONLY when considering this position as the root of the analysis : looking at thermography, various scafolds are calculated recursively till the root and eventually, only on the root, the miai value is defined as the basis of the mast.
In my approach, when I am using the terme "miai value" I always consider the considered position as the root of the tree analysed.
On the other hand, my understanding of your approach is that you use a miai value (like vb or ve) in the subtree and this miai value depends on the above part of the tree in order to determine whether or not a branch is sente. If it is true then what is your definition of such intermediate miai value? I do not see clearly how you can decide that a branch is sente. If you know in advance the value va then you may know if the branch of a subtree is sente or not but this value va will be known only at the end of the process. For that reason I do not really understand how do you proceed.
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

Code: Select all

                             A
                            / \
                           /   \
                          /     \
                         B(vb)   C
                        / \     .
                       /   \   x
                      /     \ .
                     ?       E

calling vb the miai value of B position and calling x the black gain between position C and position E, and assuming x > 0 then, the statement I developped in my previous post can be summarized as follows:
if vb < x then position A is gote and va = x/2 + vb/2
if vb > x then position A is sente for black and va = x


Let me show you how you can use the result above to calculate the miai value of the following (simple) corridor
Click Here To Show Diagram Code
[go]$$
$$ -------------------------
$$ | X X . X X . X X . X . .
$$ | X X O X X O . O O X . .
$$ | X . O O O O O O . X . .
$$ | X . O . . . . . . . . .
$$ | O O O . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . . .
$$ -------------------------[/go]
The corresponding tree is the following:

Code: Select all

                             A
                            / \
                           /   \
                          /     \
                         B       C
                        / \     .
                       /   \   6
                      /     \ .
                     D       E
                    / \     .
                   /   \   9
                  /     \ .
                 F...14..G
You see that when black plays three times locally (and white plays three tenuki) then black gains 6 + 9 + 14

What is the miai value of the initial position A?
If you apply the thermography process then you have to calculate recursively various scafolds till the root.
Instead of scafolds you may also, for such simple corridor, calculate recursively the count, the miai value and perhaps the gain of each move.

My point is that you have OC to evaluate each leaf and, for intermediate nodes, you have only to calculate recursively the miai value of the node and nothing else.
Let's procede:
Firstly you calculate vd miai value : obviously vd = 7
Secondly you calculate vb miai value : 7 (vd) < 9 (g-e) => B is a gote position => vb = (7+9)/2 => vb = 8
Thirdly you calculate va miai value : 8 (vb) > 6 (e-c) => A is black sente => va = 6

Code: Select all

                             A(6)
                            / \
                           /   \
                          /     \
                         B(8)    C
                        / \     .
                       /   \   6
                      /     \ .
                     D(7)    E
                    / \     .
                   /   \   9
                  /     \ .
                 F...14..G
How can you be more efficient?
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

Gérard TAILLE wrote:I only assume that the environment is ideal.
Ok, but you need to clarify which kind of ideal environment you presume. Mine? Bills? Or rather Berlekamp's rich environment?
Let's try this reasonning:

Code: Select all

               A
              / \
             /   \
            B     C
           / \ 
          /   \
         ?     E
if va < vb then black AB move is sente and white have to answer with BE => va = e (e - c with c = 0)
Ok.
if va > vb then:
White to play => white plays AC and black play in the environment => score1 = 0 + t = t
For Black to gain t in the environment, you are making some implicit assumption(s). If you used my ideal environment, starting in it were worth t/2. Since you account t, you might have a different study approach, such as "White makes the first move and Black makes the last move in each variation". Or maybe you consider both players' starts but demand an equal number of moves or whatnot. Please clarify!
Black to play => black plays AB gote and white plays in the environment.
Ok.
Then, when temperature of the environment drops to vb, because vb is the miai value of B we can assume that white will play BE and black will play in the environment
Why can we assume a) White continues locally and b) B is a local gote?
With this reasonning I do not mind if a ko exist in the subtree of B.
You wish. However, how do we know that B is not Black's simple sente, Black's long gote, Black's long sente or a ko?
to gain vb points
You assume the miai value (usually: the move value) vb of B. Why would this necessarily imply that White's gain on BE is vb? It would be vb if B were a simple gote, but see above (we do not know yet that it is).
=> score2 = -t + vb + e
You add the gains -t + vb and then add the count e. Sure, if the gains are right, we may do such.
you can now calculate va:
score1 = score2 => t = -t + vb + e => 2t = (vb + e) / 2
You start by studying the equality score1 = score2. Not doing your work, please explain what is the purpose of considering this equality and why does it express this purpose?

t = -t + vb + e <=> 2t = vb + e <=> t = (vb + e) / 2 and not, as you write (accidentally?) 2t = (vb + e) / 2.
and va = vb/2 + e/2
Eventually you can conclude that va = min (e, e/2 + vb/2)
Please explain both steps!

(I have not read the next messages yet.)
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

RobertJasiek wrote:Ok, but you need to clarify which kind of ideal environment you presume. Mine? Bills? Or rather Berlekamp's rich environment?
I do not know in detail the definition of the various ideal environment you mentionned but I think my reasonning works with any of these environments
RobertJasiek wrote:For Black to gain t in the environment, you are making some implicit assumption(s). If you used my ideal environment, starting in it were worth t/2. Since you account t, you might have a different study approach, such as "White makes the first move and Black makes the last move in each variation". Or maybe you consider both players' starts but demand an equal number of moves or whatnot. Please clarify!
As usual I consider both players' starts but demand an equal number of moves or whatnot.
RobertJasiek wrote:Why can we assume a) White continues locally and b) B is a local gote?
When temperature of the environment is greater than vb then it is correct for black to play in the environement (it may happen that a local black move could also be correct but playing in the environment is always correct).
When temperature of the environment is lesser than vb then the only correct move for black is to play locally (playing in the environment is not correct)
When temperature of the environment is equal to vb the situation is ambiguous and it is correct to play either in the environment or locally.
Note : the situation for white is exactly the same.

As a consequence assume temperature drops to vb.
If it is black to play it is correct to play in the environement and it is correct for white to answer locally
If it is white to play it is correct to play locally and it is correct for black to answer in the environment.

In any case I can always assume that white will play locally while black will play in the environement.
RobertJasiek wrote:Why can we assume a) ... and b) B is a local gote?
It does not matter if B is a local gote because I can assume that white will play locally while black will play in the environment
RobertJasiek wrote:You wish. However, how do we know that B is not Black's simple sente, Black's long gote, Black's long sente or a ko?
Here again it doesn't matter because black will not play locally
RobertJasiek wrote:You assume the miai value (usually: the move value) vb of B. Why would this necessarily imply that White's gain on BE is vb? It would be vb if B were a simple gote, but see above (we do not know yet that it is).
I never said that White's gain on BE is vb. I only said that black will gain vb points by playing in the environment (when temperature of the environment has dropped to vb)
RobertJasiek wrote:You start by studying the equality score1 = score2. Not doing your work, please explain what is the purpose of considering this equality and why does it express this purpose?
t = -t + vb + e <=> 2t = vb + e <=> t = (vb + e) / 2 and not, as you write (accidentally?) 2t = (vb + e) / 2.
Thank you for the correction of my typo in the formula.
On many occasion I use this score1 = score2 to calculate a miai value and you never argue on this point. What is wrong here?
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

Gérard TAILLE wrote:I do not know in detail the definition of the various ideal environment you mentionned but I think my reasonning works with any of these environments?
My "ideal environment consists of simple gotes without follow-ups, with move values T ≥ T_1 ≥ T_2 ≥... ≥ T_N-1 > 0 and move values dropping constantly by D > 0 at N > 0 drops, with the smallest move value T_N-1 = D". [Definition 24] [22]
On many occasion I use this score1 = score2 to calculate a miai value and you never argue on this point. What is wrong here?
I do not know yet if it is right or wrong here. I do not always study your texts closely enough to be sure whether your earlier instances of such score equations have always been right. I am cautious and do not make the assumption that because something worked in a different study instance it needs to work again for a particular new study instance. Until there is a general theorem, if possible, one must verify validity each time afresh. Here I am looking a bit more carefully so you won't get away with "I have done it before":)
When temperature of the environment is greater than vb then it is correct for black to play in the environement (it may happen that a local black move could also be correct but playing in the environment is always correct).
When temperature of the environment is lesser than vb then the only correct move for black is to play locally (playing in the environment is not correct)
When temperature of the environment is equal to vb the situation is ambiguous and it is correct to play either in the environment or locally.
Note : the situation for white is exactly the same.
Let me see.. You are making very strong claims here... B can be a simple gote without follow-up, simple gote with simple follow-up, simple sente or some Black's long type. For long types, I have not studied it in environments yet so your claim is premature (you also have not studied it in environments in general yet). For now, let me restrict it to simple types (from B, at most two plays starting with Black). So what have been my results?


Case B is a simple gote without follow-up:

"Presuppositions
Suppose the starting player's value perspective, simple gotes without follow-ups and with the move values T_1 ≥ T_2 ≥ ... ≥ T_N ≥ 0.
Theorem 11 [decreasing order]
Playing in order of decreasing-or-constant move values is correct." [22]

So what you say is correct for B being a simple gote without follow-up.


Case B is a simple local endgame with (Black's) follow-up:

"Theorem 62 [creator's perspective and start, late endgame, low temperature]
If T ≤ F, the creator starts
- in the environment or locally if M_SENTE ≤ 2∆T_1 or
- locally if M_SENTE > 2∆T_1.

Theorem 63
[preventer's perspective and start, late endgame, low temperature]
If T ≤ F, the preventer starts
- in the environment if M_SENTE ≤ 2∆T or
- locally if M_SENTE ≥ 2∆T.

Theorem 68 [creator's perspective and start, late endgame, high temperature]
If T > F, the creator starts
- in the environment if 2T - M_SENTE - F ≥ Ω,
- locally if 2T - M_SENTE - F ≤ Ω.

Theorem 69
[preventer's perspective and start, late endgame, high temperature]
If T > F, the preventer starts
- in the environment if M_SENTE + F - 2T ≤ Ω,
- locally if M_SENTE + F - 2T ≥ Ω.

Theorem 84 [early endgame, low temperature, creator]
If T ≤ F and T_1, T_2,... form an ideal environment, as a good approximation, the creator starts
- in the environment or locally if M_SENTE ≤ T_1,
- locally if M_SENTE > T_1.

Theorem 85 [early endgame, low temperature, preventer]
If T ≤ F and T, T_1,... form an ideal environment, as a good approximation, the preventer starts
- in the environment if M_SENTE ≤ T,
- locally if M_SENTE ≥ T.

Theorem 89
[early endgame, starting player's perspective, high temperature, conclusion]
If F < T, it is a good approximation that the starting player starts
- in the environment if M_GOTE ≤ T,
- locally if M_GOTE ≥ T.

Theorem 90
[early endgame, starting player's perspective, high temperature, sente]
If F < T and we have a local sente, it is a good approximation that the starting player starts in the environment."

Needless to say, I have given examples for all the cases of the theorems. [22] [23]

Hence, in the case of B being a simple local endgame with (Black's) follow-up, your statements are only (approximately) correct during the early endgame at high temperature if B is a (here: Black's) simple sente. For all other cases of Black or White starting and low or high temperature relative to Black's follow-up move value F, you are wrong because both cases of correct play locally or in the environment can occur!

Hence, your later conclusions might be wrong, too.

References: https://www.lifein19x19.com/viewtopic.p ... 45#p143245
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

Oops I did not expect to try and understand your own theory.
Can you just gives us an example of tree that might cause difficulties with my proposal?

Anyway, if you want really a discussion of my proposal taking as a basis your own theory then can you clarify the following points:
RobertJasiek wrote: Theorem 68 [creator's perspective and start, late endgame, high temperature]
If T > F, the creator starts
- in the environment if 2T - M_SENTE - F ≥ Ω,
- locally if 2T - M_SENTE - F ≤ Ω.
what is the meaning of F and Ω ?
RobertJasiek wrote: Hence, in the case of B being a simple local endgame with (Black's) follow-up, your statements are only (approximately) correct during the early endgame at high temperature if B is a (here: Black's) simple sente. For all other cases of Black or White starting and low or high temperature relative to Black's follow-up move value F, you are wrong because both cases of correct play locally or in the environment can occur!

Hence, your later conclusions might be wrong, too.
I suspect our theories have not the same objective. If it is the case then it might also happen that neither theory is wrong.
BTW why have you avoid the wording "miai value"? IOW is there a difference between the "miai value" of a position (defined by Bill?) and your "move value"? If yes can you show us a position or a tree for which the "miai value" and the "move value" are different.
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

For an example in an ideal environment, I might find time later.

F is the local follow-up move value.

Ω is quite complicated and beyond the scope of this thread. It is an alternating sum of the tail of smallest move values with some difficulties for signs etc. Naively, just imagine that it can be about 0 in simple examples. Consult the references for details.

CGT uses miai value and has some intricate details, which we go players usually do not need. Move value is a simpler concept without CGT overhead. Bill liked miai value because he was familiar with CGT. I like move values because I like simplicity. (That's why I study things in all details for years or some decade to ventually reveal the simplicity. Mathematicians, you know, are lazy people, so they work harder than everybody else so that then they can be lazy by simply applying the results. Well, that was the running joke at university, but it is true...)

Your study object or aim (I would not call it a theory yet,) may be different from mine and maybe you will find some result for "ladder-trees". However, even so you must proceed correctly. Never may maths rely on unproved statements. If you presume statements, first write them as definitions or propositions, which you prove. Wishful thinking is for noobs among the go players but not for mathematicians.
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Re: Cards or app for miai-value based endgame practice?

Post by Gérard TAILLE »

RobertJasiek wrote: For all other cases of Black or White starting and low or high temperature relative to Black's follow-up move value F, you are wrong because both cases of correct play locally or in the environment can occur?

Hence, your later conclusions might be wrong, too.
What is wrong if both cases of correct play locally or in the environment can occur!
On contrary it looks like my reasonning works perfectly.
The best way to show that a reasonning is not correct is always to show a counter example.
For all the trees I analysed it works quite well.
It might not work with YOUR "move value" definition but because I do not know your definition I cannot prove it works in your theory.
Please try to show a counter example otherwise the discussion will be too difficult (I do not know your theory and I have not yet finalised my own defintions of move value and ideal environment).
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Re: Cards or app for miai-value based endgame practice?

Post by RobertJasiek »

Click Here To Show Diagram Code
[go]$$B Example 3 for theorem 68
$$----------------------
$$|X X X X O O O O O O .
$$|. O X X O X X O X O O
$$|X O X X O X X O X X O
$$|X O X X O X X O X X O
$$|X O O . O X X O X O O
$$|X . O O O X X O . O .
$$|. O O X O X X O X O .
$$|X O X X O . O O X O .
$$|X O . O O X X X X O .
$$|X X X X X X . . X O .
$$|. . . . . . . . X O .[/go]
"Example 3: We have M_SENTE = 10, F = 10.5, T = 12, T_1 = 6, T_2 = 3 and T > F <=> 12 > 10.5. Due to the even number 0 of moves in the environment larger than F and excluding T, a plus sign starts Ω = F - 2(T_1 - T_2) = 10.5 - 2(6 - 3) = 4.5. According to theorem 68, the black creator starts locally as 2T - M_SENTE - F ≤ Ω <=> 2*12 - 10 - 10.5 ≤ 4.5 <=> 3.5 ≤ 4.5." [22]

Mandatory local start despite high temperature! You can also imagine the local endgame during the early endgame and draw its tree from B. I am not suprised that you could not find such an example easily; the unusual values made the difficulty of finding some of intermediate level. It is by far not the rarest, most difficult kind of endgame examples though; for the real difficulties (type a) late endgame with gote and sente options and mandatory start in the environment at low temperature; type b) the only correct choice gives tedomari to the opponent), I needed three to four days per first example.
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