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VH+ by Pat (game 0040)

 
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Sat Jun 28, 2008 12:59 pm    Post subject: VH+ by Pat (game 0040) Reply with quote

Code:

+-------+-------+-------+
| 9 . . | . . 4 | . . 2 |
| . 8 . | . 3 . | . 5 . |
| . . 7 | 9 . . | . . . |
+-------+-------+-------+
| . . 2 | . . . | . . 6 |
| . 4 . | . 6 . | . 1 . |
| 5 . . | . . . | 3 . . |
+-------+-------+-------+
| . . . | . . 6 | 1 . . |
| . 1 . | . 4 . | . 3 . |
| 6 . . | 2 . . | . . 8 |
+-------+-------+-------+
>>> play online
hint wrote:
A "double" w-wing doubles the w-wing
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sat Jun 28, 2008 4:21 pm    Post subject: Reply with quote

I had a few X-wings and W-wings.

One W-wing was "double", in that the pincer cells were a remote pair. The last one was extended by coloring.

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Sat Jun 28, 2008 4:46 pm    Post subject: Reply with quote

I used a variety of moves, probably not all of them necessary. They included X-Wings, both regular and finned, an ER, a Type 4 UR and a couple of W-Wings, the second of which finished it off.
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Sat Jun 28, 2008 11:27 pm    Post subject: Reply with quote

To explain the hint - after x-wings for 5 and 8 you come here:
Code:
 *--------------------------------------------------------------------*
 | 9      5      3      | 6      1      4      | 78     78     2      |
 | 4      8      6      | 7      3      2      | 9      5      1      |
 | 1      2      7      | 9     #58    @58     | 4      6      3      |
 |----------------------+----------------------+----------------------|
 | 378    79     2      | 1      5789  @35789  |>578    4      6      |
 | 37     4      89     |#58     6      379    | 2      1      579    |
 | 5      6      1      | 4      2     @789    | 3     >89     79     |
 |----------------------+----------------------+----------------------|
 | 78     79     5      | 3      89     6      | 1      2      4      |
 | 2      1      89     | 58     4      79     | 6      3      579    |
 | 6      3      4      | 2      579    1      | 57     79     8      |
 *--------------------------------------------------------------------*
The 58's in r3c5 and r5c4 are connected with strong links both for 5 and 8 in column 6 (the one for 8 is a grouped strong link or you take the one from box 8).
So we can eliminate 58 from r4c5 and - with the pair 79 in row 4 - 7 from r4c7.
Now there is another 58 w-wing in r4c7 and r5c4, connected by the 8's in row 6. It takes out 5 from r4c6 and the puzzle is solved.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sun Jun 29, 2008 12:21 am    Post subject: Reply with quote

ravel,

I saw the strong links for 5 and 8, both in Box 8. The eliminations are the same.

Keith
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Sun Jun 29, 2008 12:24 am    Post subject: Reply with quote

I would call those 58s a Remote Naked Pair. The "activating" links are not as obvious as those in a chain of 4 identical bivalues, but the logic is the same.

It is good to recall that a W-Wing was known as a Semi-Remote Naked Pair before it was christened "W-Wing" in this forum almost exactly 1 year ago. So, a "double" W-Wing is just a (whole) Remote Naked Pair.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sun Jun 29, 2008 4:55 am    Post subject: Reply with quote

Asellus wrote:
I would call those 58s a Remote Naked Pair. The "activating" links are not as obvious as those in a chain of 4 identical bivalues, but the logic is the same.

It is good to recall that a W-Wing was known as a Semi-Remote Naked Pair before it was christened "W-Wing" in this forum almost exactly 1 year ago. So, a "double" W-Wing is just a (whole) Remote Naked Pair.

Asellus,

Though the eliminations are the same, I think the logic to identify the pair is different. There are at least three cases of a remote pair, which is:

Quote:
Two cells that are not peers (are not buddies, do not "see" each other), and have the same pair of candidates, and those candidates can then be eliminated from the peers of those two cells.

(In the following, = is a strong link in an upper case candidate, - is a weak link.)

1. The cells are connected by a chain of cells having the same two candidates, for example, XY=XY=XY=XY.

2. The cells are connected by a chain having strong links in only one of the candidates, for example, XY=Xw=Xz=XY. w and z are any multi candidate strings, so long as we have strong links on X.

3. The cells are a double W-wing. There are two chains: XY-Xw=Xz-XY (which removes Y) and XY-Yw=Yz-XY (which removes X). In these two chains, only the two end cells are common.

My point is only that the logic for the eliminations may be the same, the logic for identifying the eliminations is very different. I think 1, 2, 3 above differ dramatically in their degree of difficulty.

Keith
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun Jun 29, 2008 6:41 am    Post subject: Reply with quote

I like the pattern of the givens
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