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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     |
 
 *--------------------------------------------------------------------*
 
 | 	  
 
 
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 :
 
 
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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"  
 
 
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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