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  • A proof that this quiz is easy

    From [email protected]@21:1/5 to All on Thu Nov 25 05:12:29 2021
    My titles don't lie. (At least this one doesn't, anyway).
    So I'll offer a proof that the problem below is easy:

    It happens quite frequently (if I recall correctly) that problems posed
    on this forum are attempted by nobody.
    There is therefore a high probability that this problem is attempted by
    nobody.
    If it is attempted by nobody, all the solving attempts will be correct.
    There is therefore a high probability that every single person who
    attempts the problem will solve it correctly.
    If a problem is likely to be solved correctly by all attempters, it must be
    an easy problem.
    Therefore the problem below is easy.

    Paul

    XGID=a--BBcCBC---bBA----cb-bb--:1:1:1:00:2:0:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X X | | O O O O |
    | X | | O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X O | +---+
    | O X X | | X O X X | | 2 |
    | O X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 110 O: 149 X-O: 2-0
    Cube: 2, X own cube
    X on roll, cube action

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tim Chow@21:1/5 to All on Thu Nov 25 06:20:19 2021
    XGID=a--BBcCBC---bBA----cb-bb--:1:1:1:00:2:0:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X X | | O O O O |
    | X | | O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X O | +---+
    | O X X | | X O X X | | 2 |
    | O X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 110 O: 149 X-O: 2-0
    Cube: 2, X own cube
    X on roll, cube action

    Although O is on the bar, I look at this position as primarily a
    5pt holding game. In a holding game, the holder usually relies
    on a mixture of racing vig and shot vig. Here, O is so far behind
    in the pip count that she has to rely mostly on shot vig. She
    does have some shot vig because her checker on the bar could
    enter deep in X's board, and X could have some trouble clearing
    the midpoint or even safetying the straggler. However, I don't
    think it's enough, especially since X has some gammon chances.
    D/P for me.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From [email protected]@21:1/5 to Tim Chow on Thu Nov 25 13:42:15 2021
    On Thursday, November 25, 2021 at 2:20:22 PM UTC, Tim Chow wrote:
    XGID=a--BBcCBC---bBA----cb-bb--:1:1:1:00:2:0:3:0:10
    X:Daniel O:eXtremeGammon

    Score is X:2 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X X | | O O O O |
    | X | | O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X O | +---+
    | O X X | | X O X X | | 2 |
    | O X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 110 O: 149 X-O: 2-0
    Cube: 2, X own cube
    X on roll, cube action
    Although O is on the bar, I look at this position as primarily a
    5pt holding game. In a holding game, the holder usually relies
    on a mixture of racing vig and shot vig. Here, O is so far behind
    in the pip count that she has to rely mostly on shot vig. She
    does have some shot vig because her checker on the bar could
    enter deep in X's board, and X could have some trouble clearing
    the midpoint or even safetying the straggler. However, I don't
    think it's enough, especially since X has some gammon chances.
    D/P for me.

    And it's not TG because ... ?

    Paul

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tim Chow@21:1/5 to [email protected] on Thu Nov 25 14:05:46 2021
    On Thursday, November 25, 2021 at 4:42:16 PM UTC-5, [email protected] wrote:
    And it's not TG because ... ?

    Oh, hmmm. Yes, if it's a pass and there are hardly any sequences
    that regain the market, then I guess it's probably TG. If this is part
    of your mission to show that people other than Stick cash TG
    positions too often, then score one point for you.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From [email protected]@21:1/5 to Tim Chow on Thu Nov 25 14:18:27 2021
    On Thursday, November 25, 2021 at 10:05:47 PM UTC, Tim Chow wrote:
    On Thursday, November 25, 2021 at 4:42:16 PM UTC-5, [email protected] wrote:
    And it's not TG because ... ?
    Oh, hmmm. Yes, if it's a pass and there are hardly any sequences
    that regain the market, then I guess it's probably TG. If this is part
    of your mission to show that people other than Stick cash TG
    positions too often, then score one point for you.

    ---
    Tim Chow

    It doesn't work as an example of a TG that people wrongly cash because it's actually too close to call (in my opinion) and is ultra-marginal between D/P and TG.

    It works as an example of "a quiz Tim got wrong" though. In my opinion, D/P is an ok answer because,
    with it being so marginal, no one can say this is wrong. But then the TG possibility must be mentioned
    to score any points.


    Analyzed in Rollout
    No redouble
    Player Winning Chances: 82.27% (G:14.87% B:0.17%)
    Opponent Winning Chances: 17.73% (G:1.77% B:0.05%)
    Redouble/Take
    Player Winning Chances: 81.85% (G:16.37% B:0.21%)
    Opponent Winning Chances: 18.15% (G:2.00% B:0.06%)

    Cubeless Equities: No Double=+0.778, Double=+1.564

    Cubeful Equities:
    No redouble: +1.004
    Redouble/Take: +1.441 (+0.437)
    Redouble/Pass: +1.000 (-0.004)

    Best Cube action: Too good to redouble / Pass
    Percentage of wrong take needed to make the double decision right: 0.9%

    Rollout:
    1296 Games rolled with Variance Reduction.
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.003 (+1.001..+1.007)
    Confidence Double: ± 0.011 (+1.430..+1.452)

    Double Decision confidence: 99.6%
    Take Decision confidence: 100.0%

    Duration: 48 minutes 44 seconds

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)