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Pattern game 6.48 tthsieh 5.2

 
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Wed May 02, 2012 5:51 am    Post subject: Pattern game 6.48 tthsieh 5.2 Reply with quote

Code:

 *-----------*
 |..1|2..|.3.|
 |..4|1.5|..6|
 |75.|4..|...|
 |---+---+---|
 |872|...|.4.|
 |...|...|...|
 |.6.|...|972|
 |---+---+---|
 |...|..1|.29|
 |5..|3.4|6..|
 |.2.|..6|3..|
 *-----------*
 

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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Wed May 02, 2012 2:44 pm    Post subject: Reply with quote

For the first time in ages, I had the occasion to play Sudoku and found a solution that I am unable to formulate cleanly. I would appreciate any suggestions on how to specify this solution.

Code:
*--------------------------------------------------------------------*
 | 69     89     1      | 2      689    7      | 45     3      45     |
 | 2      389    4      | 1      389    5      | 7      89     6      |
 | 7      5     c38-69  | 4      3689   389    | 2      189    18     |
 |----------------------+----------------------+----------------------|
 | 8      7      2      | 6      1359   39     | 15     4      35     |
 | 39     14     359    | 57     13457  2      | 158    6      358    |
 | 14     6     a35     |b58     14     38     | 9      7      2      |
 |----------------------+----------------------+----------------------|
 | 36     348    3678   | 578    578    1      | 48     2      9      |
 | 5      189    89     | 3      2      4      | 6      18     7      |
 | 14     2      78     | 9      78     6      | 3      5      14     |
 *--------------------------------------------------------------------*


Look at the axy-wing(35-8)r6c34+r3c3, marked abc, where r3c3 is viewed as two bivalues: 38 and 69. The xy-wing does not make any direct deletions, but does with a pincer transport: (8)r6c4-r6c6=r3c6 thereby making r3c589<>8.

The 69 bivalue in r3c3 is handled as follows:
ls(69)r3c3+r1c1-(9=3)r12c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6 thereby making r3c589<>8.

My current formulation is
[(8)r3c6=(8)r6c6-(8=5=3)r6c43-(3=8)r3c3]=[ls(69)r3c3+r1c1-(9=3)r12c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6]; r3c589<>8

Ted
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Wed May 02, 2012 3:55 pm    Post subject: Reply with quote

tlanglet wrote:
...I ... found a solution that I am unable to formulate cleanly. I would appreciate any suggestions on how to specify this solution.

Eliminating redundant SIS, your step may be viewed as the following "wing" (or "Death Blossom") based on 3B1 :
    r2c2=3 => NP(48)r7c27; r3c3=3 => NP(58)r6c34 :=> -8r7c4.
Using the same idea as in (9=3)r12c2, one can write the following simple AIC :

Code:

ALS (348)r7c27 : 8r7c27=3r7c2
3B1            :        3r2c2=3r3c3
ALS (358)r6c34 : 8r6c4========3r6c3

=> 8r7c27=8r6c4 :=> -8r7c4

If a name is wanted, one could call this a "pseudo-W Wing" Very Happy

JC
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    daj95376



    Joined: 23 Aug 2008
    Posts: 3854

    PostPosted: Wed May 02, 2012 4:07 pm    Post subject: Reply with quote

    Ted, when you start in the middle, it's a good idea to start at one end and review your logic to the opposite end.

    (8)r3c6=r6c6-(8=5)r6c4-(5=3)r6c3-r3c3=r2c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6 => r3c6=8
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    arkietech



    Joined: 31 Jul 2008
    Posts: 1834
    Location: Northwest Arkansas USA

    PostPosted: Wed May 02, 2012 4:16 pm    Post subject: Reply with quote

    JC Van Hay wrote:
    If a name is wanted, one could call this a "pseudo-W Wing" Very Happy
    Cool

    I used a different approach.
    Code:
     *--------------------------------------------------------------------*
     | 69     89     1      | 2      689    7      | 45     3      45     |
     | 2     a89+3   4      | 1      389    5      | 7      89     6      |
     | 7      5     e3689   | 4      3689   389    | 2      189    18     |
     |----------------------+----------------------+----------------------|
     | 8      7      2      | 6      1359   39     | 15     4      35     |
     | 39     14     359    | 57     13457  2      | 158    6      358    |
     | 14     6      35     | 58     14     38     | 9      7      2      |
     |----------------------+----------------------+----------------------|
     |c36    b348   d3678   | 578    578    1      | 48     2      9      |
     | 5      189    89     | 3      2      4      | 6      18     7      |
     | 14     2      78     | 9      78     6      | 3      5      14     |
     *--------------------------------------------------------------------*
    d-loop
    (3)r2c2=r7c2-(3=6)r7c1-r7c3=(6-3)r3c3=(3)r2c2 => r2c2=3; lcls
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    SudoQ



    Joined: 02 Aug 2011
    Posts: 127

    PostPosted: Wed May 02, 2012 5:31 pm    Post subject: Reply with quote

    Code:
    r1c1=6 -> r7c1=3 ->
    r3c3=6 -> r2c2=3 -> r7c2<>3

    /SudoQ
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    Marty R.



    Joined: 12 Feb 2006
    Posts: 5770
    Location: Rochester, NY, USA

    PostPosted: Wed May 02, 2012 8:19 pm    Post subject: Reply with quote

    Took me four steps.

    Skyscraper on 8

    Multi-coloring on 8

    M-Wing on 19

    XY-Wing on 693
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    tlanglet



    Joined: 17 Oct 2007
    Posts: 2468
    Location: Northern California Foothills

    PostPosted: Thu May 03, 2012 12:52 am    Post subject: Reply with quote

    Thanks to everyone that offered different views and notational schemes. I find such feedback very informative.

    Ted
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    aran



    Joined: 19 Apr 2010
    Posts: 70

    PostPosted: Thu May 03, 2012 10:51 am    Post subject: Reply with quote

    Remaining with tlanglet's original XY-wing (358 : r6c3+r3c3/r6c4) idea :
    8r3c6=XYwing=3r2c2-(3=48)r7c27-8r7c4=r6c4-r6c6=r3c6 : =>r3c6=8

    Too concise perhaps, but it's a matter of balancing between an off-putting chain and leaving a little work to the reader (should there be one).
    As to whether brackets should precede XYwing in this chain ie 8r3c6=(XYwing=...=r3c6) :
    I don't regard them as necessary : the XYwing can't exist, so it's not a possibility to be considered, and the only purpose of brackets in such circumstances is to introduce possibilities (generally two : x true/x false).
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