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Solvus Interruptus

 
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Captain Pete



Joined: 09 Jun 2007
Posts: 55
Location: Oley, PA
PostPosted: Sat Dec 22, 2007 4:47 pm    Post subject: Solvus Interruptus Reply with quote
I thought I had this one in the can until I was called away. When I returned to the puzzle, I couldn't get it moving. What's next?

Code:

+-------------+----------+------------+
| 37  5   4   | 8  2 1   | 6  9   37  |
| 16  378 16  | 37 4 9   | 5  2   378 |
| 9   2   378 | 37 6 5   | 78 4   1   |
+-------------+----------+------------+
| 5   9   378 | 6  1 238 | 4  378 278 |
| 4   378 2   | 9  5 38  | 1  378 6   |
| 368 1   368 | 4  7 238 | 9  5   28  |
+-------------+----------+------------+
| 2   6   9   | 5  8 7   | 3  1   4   |
| 78  78  5   | 1  3 4   | 2  6   9   |
| 13  4   13  | 2  9 6   | 78 78  5   |
+-------------+----------+------------+
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Sat Dec 22, 2007 5:02 pm    Post subject: Reply with quote
A W-wing then an XY-wing does the trick.

Keith
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Captain Pete



Joined: 09 Jun 2007
Posts: 55
Location: Oley, PA
PostPosted: Sat Dec 22, 2007 10:13 pm    Post subject: Reply with quote
Keith, Thanks. I haven't used w-wing before, but I think I understand it. In this puzzle, 37 in c1r1 and c4r3 allow us to eliminate the 7 in c2r2. Is that correct?
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Captain Pete



Joined: 09 Jun 2007
Posts: 55
Location: Oley, PA
PostPosted: Sat Dec 22, 2007 10:15 pm    Post subject: Reply with quote
I should have said the 37 in c4r2
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Sat Dec 22, 2007 10:25 pm    Post subject: Reply with quote
Captain Pete wrote:
Keith, Thanks. I haven't used w-wing before, but I think I understand it. In this puzzle, 37 in c1r1 and c4r3 allow us to eliminate the 7 in c2r2. Is that correct?


I think you have a typo (should be R2C4):

Code:
+-------------+----------+------------+
| 37@ 5   4   | 8  2 1   | 6  9   37# |
| 16 378% 16  | 37@4 9   | 5  2   378#|
| 9   2   378 | 37 6 5   | 78 4   1   |
+-------------+----------+------------+
| 5   9   378 | 6  1 238 | 4  378 278 |
| 4   378 2   | 9  5 38  | 1  378 6   |
| 368 1   368 | 4  7 238 | 9  5   28  |
+-------------+----------+------------+
| 2   6   9   | 5  8 7   | 3  1   4   |
| 78  78  5   | 1  3 4   | 2  6   9   |
| 13  4   13  | 2  9 6   | 78 78  5   |
+-------------+----------+------------+

The W-wing @ <37> in R1C1 and R2C4 with strong link # on <3> in C9 takes out <7> % in R2C2.

There may well be other moves. This was the first one I spotted. (There are no X-, XY-, or XYZ-wings in the position you posted.)

Keith
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
PostPosted: Sat Dec 22, 2007 11:51 pm    Post subject: Reply with quote
There is another move: A Kite on <7> pivoting in Box 1.
Code:
+-------------+----------+--------------+
|v37  5   4   | 8  2 1   | 6  9   p37   |
| 16  378 16  | 37 4 9   | 5  2    378  |
| 9   2  v378 | 37 6 5   | 78 4    1    |
+-------------+----------+--------------+
| 5   9  p378 | 6  1 238 | 4  378 #2-78 |
| 4   378 2   | 9  5 38  | 1  378  6    |
| 368 1   368 | 4  7 238 | 9  5    28   |
+-------------+----------+--------------+
| 2   6   9   | 5  8 7   | 3  1    4    |
| 78  78  5   | 1  3 4   | 2  6    9    |
| 13  4   13  | 2  9 6   | 78 78   5    |
+-------------+----------+--------------+

The Pincers are "p", Pivots "v", and the Victim "#". (This can also be seen as an ER in Box 3 with strong link in c3.) This solves the puzzle.

There is also an interesting 6-cell DP in the left tower that eliminates several <8>s, though it doesn't solve the puzzle:
Code:
+-----------------+------------+------------+
| 37   5     4    | 8  2  1    | 6  9   37  |
|a16   378  a16   | 37 4  9    | 5  2   378 |
| 9    2     378  | 37 6  5    | 78 4   1   |
+-----------------+------------+------------+
| 5    9    #37-8 | 6  1  238  | 4  378 278 |
| 4   #37-8  2    | 9  5  38   | 1  378 6   |
|b368  1    b368  | 4  7 #23-8 | 9  5  #2-8 |
+-----------------+------------+------------+
| 2    6     9    | 5  8  7    | 3  1   4   |
| 78   78    5    | 1  3  4    | 2  6   9   |
|c13   4    c13   | 2  9  6    | 78 78  5   |
+-----------------+------------+------------+

The "b" cells cannot be {36}, so one of them must be <8>, eliminating <8>s from the cells marked "#".
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