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Clement
Joined: 24 Apr 2006
Posts: 1113
Location: Dar es Salaam Tanzania
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 Posted: Mon May 17, 2010 10:17 pm Post subject: May 18 VH |
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| UR Type 4 (25) in r34c13 removes the 5's in r3c13 solving the puzzle. |
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prakash
Joined: 02 Jan 2008
Posts: 67
Location: New Jersey, USA
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| Posted: Tue May 18, 2010 1:11 am Post subject: |
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| XY Wing 467 with pivot at r3c9 cracks the puzzle open. |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Tue May 18, 2010 7:14 am Post subject: |
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Perhaps a more dramatic use of the UR(25) is the Type 3 approach, though same end result!
Type 3 UR(25) 69 psuedo-cell, naked triplet(469) in r3, r3c6<>46, r3c2<>69; naked quad(3679) in b1, r2c2<>36, r2c3<>367
Carnage  ! |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Tue May 18, 2010 1:29 pm Post subject: |
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| peterj wrote: | Perhaps a more dramatic use of the UR(25) is the Type 3 approach, though same end result!
Type 3 UR(25) 69 psuedo-cell, naked triplet(469) in r3, r3c6<>46, r3c2<>69; naked quad(3679) in b1, r2c2<>36, r2c3<>367
Carnage ! |
Don't you just love it when you find a pattern like that; Carnage Indeed 
For completeness sake, we could also look at the implications outside of the AUR cells.
(2): a x-wing overlay, thus no implications
(5): the only locations in the row/box houses is (5)r3c2
Thus, to prevent the deadly pattern r3c2=5 to complete the puzzle.
Even more carnage. 
Ted |
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sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
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| Posted: Wed May 19, 2010 12:57 pm Post subject: type 4 UR |
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| can you please explain a Type 4 UR. I do know some URs but not a type 4. If you could explain it, that would be helpful. thanks. |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Wed May 19, 2010 2:41 pm Post subject: |
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| Quote: | | can you please explain a Type 4 UR. I do know some URs but not a type 4. If you could explain it, that would be helpful. thanks. |
For the 25 UR there are only two <2>s in R3
So remove the <5>s in R3C13
…and if you are like me – don’t worry why. 
| Code: |
+---------------+---------+---------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| 2569 1569 256 | 8 7 146 | 3 49 46|
+---------------+---------+---------+
| 25 7 25 | . . | . . . |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Wed May 19, 2010 4:28 pm Post subject: |
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| cgordon wrote: |
| Code: |
+---------------+---------+---------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| 2569 1569 256 | 8 7 146 | 3 49 46|
+---------------+---------+---------+
| 25 7 25 | . . | . . . |
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Type 4: One of R3C13 must be 2 - there are no other candidates 2 in R3. To avoid the deadly pattern (DP), neither of R3C13 can be 5. Solving R3C2 as 5.
Type 3: R3C13 must include at least one of 69 to break the DP. With R3C89 it forms a triple 469, solving R3C6 as 1.
Keith |
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Clement
Joined: 24 Apr 2006
Posts: 1113
Location: Dar es Salaam Tanzania
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| Posted: Wed May 19, 2010 6:02 pm Post subject: Mar 18 VH |
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| Alternatively, we can say that, a Type 4 UR occurs when one of the row, column in the grid of UR contains a conjugate pair of one of the possible candidate in creating the deadly pattern, 2 in our case. In this puzzle we have to remove one of the original pair of possibilities (5) in the two cells r3c13 to avoid the deadily pattern. In Type 1 UR we could have removed the 25 in one corner with extra candidates. |
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sheryl
Joined: 24 Sep 2007
Posts: 64
Location: New York
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| Posted: Wed May 19, 2010 6:09 pm Post subject: URs |
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| Thank you! |
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