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M-wing.

 
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Sat Jul 12, 2008 6:34 pm    Post subject: M-wing. Reply with quote

Here is an interesting puzzle, Jsudoku generated.
(JSudoku does not support M-wings at this time. July 12th 2008)

One M-wing or:

1 X-Wing
1 Finned X-Wing
1 XY-Wing
1 XYZ-Wing
1 Uniqueness Test 3
1 Y-Wing.

Code:
. 5 .|. 6 .|. 8 .
. . .|. . 4|. . 7
. 1 3|. 8 .|. . .
-----+-----+-----
. . .|5 . 6|. 7 .
. . .|. . .|4 . 9
6 4 .|. . 2|. . .
-----+-----+-----
. . .|. . .|9 . .
2 . .|4 . .|1 . 6
5 8 .|3 . .|. . .
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keith



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

PostPosted: Sat Jul 12, 2008 9:00 pm    Post subject: Reply with quote

Wapati, I fouund:
Code:
+-------------+-------------+-------------+
| 479 5   247 | 279 6   379d| 23a 8   1   |
| 89  6   28  | 1  -35  4   | 35  29  7   |
| 79  1   3   | 279 8   579 | 6   249 245 |
+-------------+-------------+-------------+
| 138 9   18  | 5   4   6   | 28b 7   23c |
| 378 2   5   | 78  137 137 | 4   6   9   |
| 6   4   78  | 789 379f 2  | 58  1   35e |
+-------------+-------------+-------------+
| 14  37  14  | 6   2   57  | 9   35  8   |
| 2   37  9   | 4   57  8   | 1   35  6   |
| 5   8   6   | 3   19  19  | 7   24  24  |
+-------------+-------------+-------------+
a and c are a complementary pair, connected abc by strong links on <2>. The M-wing is dabc; any cell that sees both ends cannot be <3>. We can color on <3>, cef, eliminating <3> in R2C5, solving the puzzle.

Is this what you had in mind?

Keith

(It's been a good few days for M-wings Laughing )
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sat Jul 12, 2008 9:21 pm    Post subject: Reply with quote

Code:
.---------------.---------------.---------------.
| 479  5    247 | 279  6    379 | 23   8    1   |
| 89   6    28  | 1   -35   4   |A35   29   7   |
| 79   1    3   | 279  8    579 | 6    249 *245 |
:---------------+---------------+---------------:
| 138  9    18  | 5    4    6   | 28   7    23  |
| 378  2    5   | 78   137  137 | 4    6    9   |
| 6    4    78  | 789 C379  2   | 58   1   B35  |
:---------------+---------------+---------------:
| 14   37   14  | 6    2    57  | 9    35   8   |
| 2    37   9   | 4    57   8   | 1    35   6   |
| 5    8    6   | 3    19   19  | 7    24   24  |
'---------------'---------------'---------------'


here is another one A and B complimentary pairs on strong links on 5
3 then is strong linked over to C r6c5, removes 3 in r2c5.

(3=5)r2c7-(5)r3c9=(5-3)r6c9=(3)r6c5; r2c5<>3
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Steve R



Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England

PostPosted: Sat Jul 12, 2008 9:51 pm    Post subject: Reply with quote

Here’s another variant:

Code:
+--------------+--------------+-------------+
|  479 5   247 | 279 6   *379 | 23a 8   1   |
|  89  6   28  | 1   35   4   | 35  29  7   |
|  79  1   3   | 279 8    579 | 6   249 245 |
+--------------+--------------+-------------+
| =138 9   18  | 5   4    6   | 28  7   23c |
| =378 2   5   | 78  137 *137 | 4   6   9   |
|  6   4   78  | 789 379  2   | 58  1   35  |
+--------------+--------------+-------------+
|  14  37  14  | 6   2    57  | 9   35  8   |
|  2   37  9   | 4   57   8   | 1   35  6   |
|  5   8   6   | 3   19   19  | 7   24  24  |
+--------------+--------------+-------------+


The (23)s in the cells a and c used by Keith could be the pincers of a W-Wing. The conjugates for 3 marked * in column 6 do not quite link them but add the conjugates marked = in column 1 and the link is complete.

So 2 can be eliminated from r4c7.

Steve
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Sat Jul 12, 2008 9:55 pm    Post subject: Reply with quote

Hi keith,

keith wrote:
Wapati, I fouund:
Code:
+-------------+-------------+-------------+
| 479 5   247 | 279 6   379d| 23a 8   1   |
| 89  6   28  | 1  -35  4   | 35  29  7   |
| 79  1   3   | 279 8   579 | 6   249 245 |
+-------------+-------------+-------------+
| 138 9   18  | 5   4   6   | 28b 7   23c |
| 378 2   5   | 78  137 137 | 4   6   9   |
| 6   4   78  | 789 379f 2  | 58  1   35e |
+-------------+-------------+-------------+
| 14  37  14  | 6   2   57  | 9   35  8   |
| 2   37  9   | 4   57  8   | 1   35  6   |
| 5   8   6   | 3   19  19  | 7   24  24  |
+-------------+-------------+-------------+
a and c are a complementary pair, connected abc by strong links on <2>. The M-wing is dabc; any cell that sees both ends cannot be <3>. We can color on <3>, cef, eliminating <3> in R2C5, solving the puzzle.

Is this what you had in mind?

Keith

(It's been a good few days for M-wings Laughing )


Well, it is a horse of a different color. Wink

I don't do colors but the elimination is valid so you know what you are doing. The one I had in mind is shown by storm_norm.

Your pattern, to me, is an M-wing chain. You can add an even number of strong links to the ends of an M-wing and have a valid pattern. If we use all the cells that you have lettered, your colorful elimination is duplicated. Good fun!

Edited to add: Cool post Steve.
A swordfishy W-wing, gotta like it Exclamation
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Asellus



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

PostPosted: Sun Jul 13, 2008 9:40 pm    Post subject: Reply with quote

As Keith pointed out on a neighboring thread, whenever you have a remote pair that is both complementary and a W-Wing, you can set both bivalues to the pincer digit of the W-Wing.

So, those 23's (ac in the prior post) both become <2>. At least one of them must be <2> (W-Wing) and they must be the same (complementary pair). So, they must both be <2>.

It can be seen as a Medusa multi-coloring trap that collapses one of the two clusters:
Code:
+--------------+---------------+---------------+
| 479  5   247 | 279 6    3X79 | 2X3x 8   1    |
| 89   6   28  | 1   35   4    | 35   29  7    |
| 79   1   3   | 279 8    579  | 6    249 245  |
+--------------+---------------+---------------+
| 13Y8 9   18  | 5   4    6    | 2x8  7   2X3x |
| 3y78 2   5   | 78  137  13x7 | 4    6   9    |
| 6    4   78  | 789 379  2    | 58   1   35   |
+--------------+---------------+---------------+
| 14   37  14  | 6   2    57   | 9    35  8    |
| 2    37  9   | 4   57   8    | 1    35  6    |
| 5    8   6   | 3   19   19   | 7    24  24   |
+--------------+---------------+---------------+

The Xx and Yy clusters are weak-link bridged on xy in r5, making XY the strong pair. This traps the 3x in r4c9 and collapses the Xx cluster (making all x values false and all X values true).

The W-Wing is activated by the (otherwise useless) Skyscraper (aka Turbot Fish or Color Wing or Multi-Coloring on 3) in c16.
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keith



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

PostPosted: Mon Jul 14, 2008 2:26 am    Post subject: Reply with quote

So, why is it, this weekend, that M-wings seem to be able to solve all puzzles? Razz Razz
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keith



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

PostPosted: Mon Jul 14, 2008 2:49 am    Post subject: Reply with quote

Asellus wrote:
As Keith pointed out on a neighboring thread, whenever you have a remote pair that is both complementary [pair] and a W-Wing, you can set both bivalues to the pincer digit of the W-Wing.

No, Keith would say, "a pair (that is not in the same house)".

Not: "a remote pair".

(A remote pair is, by definition, not a complementary pair.)

Keith
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Mon Jul 14, 2008 7:02 pm    Post subject: Reply with quote

There is a w-wing (35) with strong link on 5 either in box 3 or row 3 or col 7
It, too, solves the puzzle in one move

Code:

+--------------------------+--------------------------+--------------------------+
| 479     5       247      | 279     6       379      | 23      8       1        |
| 89      6       28       | 1       35*     4        | 35      29      7        |
| 79      1       3        | 279     8       579      | 6       249     245      |
+--------------------------+--------------------------+--------------------------+
| 138     9       18       | 5       4       6        | 28      7       23       |
| 378     2       5        | 78      137     137      | 4       6       9        |
| 6       4       78       | 789    -379     2        | 58      1       35*      |
+--------------------------+--------------------------+--------------------------+
| 14      37      14       | 6       2       57       | 9       35      8        |
| 2       37      9        | 4       57      8        | 1       35      6        |
| 5       8       6        | 3       19      19       | 7       24      24       |
+--------------------------+--------------------------+--------------------------+
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Asellus



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

PostPosted: Mon Jul 14, 2008 10:53 pm    Post subject: Reply with quote

Keith wrote:
No, Keith would say, "a pair (that is not in the same house)".

Not: "a remote pair".

(A remote pair is, by definition, not a complementary pair.)

I have always said "Remote Naked Pair" in such cases to be clear about what I mean. For me, "remote pair" just means any pair of matching bivalues in cells that are not peers, i.e. they are "remote." It's what you look for when scanning for possible M-Wings or W-Wings. However, I just checked and see that Sudopedia uses "Remote Pair" to mean what I and others refer to as "Remote Naked Pair." So, I'll avoid using the term "remote pair" for any purpose because I now find it to be confusing.
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