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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Wed May 02, 2012 5:51 am    Post subject: Pattern game 6.48 tthsieh 5.2 |   |  
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				|  	  | 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
 
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				|  Posted: Wed May 02, 2012 2:44 pm    Post subject: |   |  
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				| 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     |
 *--------------------------------------------------------------------*
 
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 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
 
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				|  Posted: Wed May 02, 2012 3:55 pm    Post subject: |   |  
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				|  	  | 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
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 If a name is wanted, one could call this a "pseudo-W Wing"
   
 JC
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		| daj95376 
 
 
 Joined: 23 Aug 2008
 Posts: 3854
 
 
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				|  Posted: Wed May 02, 2012 4:07 pm    Post subject: |   |  
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				| 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
 
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				|  Posted: Wed May 02, 2012 4:16 pm    Post subject: |   |  
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				|  	  | JC Van Hay wrote: |  	  | If a name is wanted, one could call this a "pseudo-W Wing"  | 
   
 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
 
 
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				|  Posted: Wed May 02, 2012 5:31 pm    Post subject: |   |  
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				|  	  | Code: |  	  | r1c1=6 -> r7c1=3 -> r3c3=6 -> r2c2=3 -> r7c2<>3
 
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 /SudoQ
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Wed May 02, 2012 8:19 pm    Post subject: |   |  
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				| 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
 
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				|  Posted: Thu May 03, 2012 12:52 am    Post subject: |   |  
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				| 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
 
 
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				|  Posted: Thu May 03, 2012 10:51 am    Post subject: |   |  
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				| 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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