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		daj95376
 
 
  Joined: 23 Aug 2008 Posts: 3854
 
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				 Posted: Mon Jul 25, 2011 4:04 pm    Post subject: Puzzle 11/07/25: B XY | 
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				The extraneous steps may drive you to drink!
 
 
 	  | Code: | 	 		   +-----------------------+
 
 | . . 5 | . 9 . | 3 . . |
 
 | . 7 . | 5 4 . | 1 . . |
 
 | 1 . . | . . . | . . . |
 
 |-------+-------+-------|
 
 | . 4 . | 1 . 2 | . 8 . |
 
 | 8 5 . | . 6 . | . . 1 |
 
 | . . . | 8 . 4 | 9 . 6 |
 
 |-------+-------+-------|
 
 | 6 9 . | . . 5 | . . . |
 
 | . . . | 6 . . | . 9 . |
 
 | . . . | . 3 9 | . . 4 |
 
 +-----------------------+
 
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Play this puzzle online at the Daily Sudoku site | 
			 
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		peterj
 
 
  Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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				 Posted: Tue Jul 26, 2011 7:24 am    Post subject:  | 
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				Two wings - already there on the drink front so extraneous steps had no effect...
 
 	  | Quote: | 	 		  w-wing(2-8) r3c5, r9c2 ; r3c2<>8
 
xy-wing(28-6) r3c5 ; r3c6<>6 | 	 
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		tlanglet
 
 
  Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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				 Posted: Wed Jul 27, 2011 2:39 pm    Post subject:  | 
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				Two "Conflict" steps........
 
 
(3=1)r8c2-aur(13)r68c23[(1)r7c3=(3)r2c3*]-(3=2)r2c1#-(2=6)r2c8-(6=8)r2c6-(8=2)r3c5-r78c5=r9c4-r9c2=r13c2- Conflict#; r2c3<>3, r7c3=1, r8c3*<>3(?)
 
 
axy-wing (28-6)b2q86+r3c2=(8)r3c2-(8=2)r9c2-r9c4=r1c4-(2=8r3c5- Conflict; r3c2<>8, r3c6<>6
 
 
In the first step, I have marked a deletion when within the aur, r2c3 is set to 3, but later it is determined that r2c3 can not be 3 due to a conflict.
 
Question: Is the deletions based on r2c3=3 valid?
 
 
Finally the first step is not required; the second move is a one-stepper.
 
 
Ted | 
			 
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		daj95376
 
 
  Joined: 23 Aug 2008 Posts: 3854
 
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				 Posted: Wed Jul 27, 2011 3:40 pm    Post subject:  | 
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				Ted, the first step can be broken into two, more manageable steps.
 
 
 	  | Code: | 	 		  (2=6)r2c8-(6=8)r2c6-(8=2)r3c5-r78c5=r9c4-r9c2=(2)r13c2; r2c1<>2=3
 
 
 r68c23  <13> UR Type 4.2245             <> 1    r68c3
 
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As for the first part of your chain ...
 
 
 	  | Code: | 	 		  (3=1)r8c2-aur(13)r68c23[(1)r7c3=(3)r2c3]; r8c3<>3
 
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... doesn't r8c3<>3 follow from (a Hidden UR ?):
 
 
 	  | Code: | 	 		  (3*)r8c3 - (3=1*)r8c2 - (1   )r6c2 = (1*)r6c3  =>  *DP in <13>
 
                        ( =3*)r6c2
 
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		Luke451
 
 
  Joined: 20 Apr 2008 Posts: 310 Location: Southern Northern California
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				 Posted: Wed Jul 27, 2011 6:42 pm    Post subject:  | 
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				 	  | tlanglet wrote: | 	 		  | axy-wing (28-6)b2q86+r3c2=(8)r3c2-(8=2)r9c2-r9c4=r1c4-(2=8)r3c5- Conflict; r3c2<>8, r3c6<>6 | 	  
 
V cool almost xy Ted, I like it.  A wee point:  I don't understand why you've started ending your chains with "-conflict" rather than writing a standard ending that proves the conflict; -(8=6)r2c6 =>r3c6<>6 | 
			 
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		tlanglet
 
 
  Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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				 Posted: Thu Jul 28, 2011 1:17 pm    Post subject:  | 
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				[quote="Luke451"] 	  | tlanglet wrote: | 	 		  | axy-wing (28-6)b2q86+r3c2=(8)r3c2-(8=2)r9c2-r9c4=r1c4-(2=8)r3c5- Conflict; r3c2<>8, r3c6<6>r3c6<>6 | 	  
 
Luke, Great Question (as I constantly hear folks respond)!
 
 
First, I am not sure why I stopped with "-conflict" but I also (always?) have in the past.  It is at the same stage as when a deletion normally occurs: (8)r3c2- ...... =(8)r3c5. Also, I am not sure how to flag the conflict otherwise in order to delete the source of the conflict. I guess ideally that it would be best to continue the chain to the normal end but flag the conflict within the chain.
 
 
Ted | 
			 
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