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No XY/XYZ-Wings: Set A Puzzle 9

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun Nov 02, 2008 7:14 pm    Post subject: No XY/XYZ-Wings: Set A Puzzle 9 Reply with quote

Same Rules! I don't think this puzzle is going to be cooperative at all Exclamation

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



Joined: 19 Sep 2005
Posts: 3165
Location: near Detroit, Michigan, USA

PostPosted: Sun Nov 02, 2008 8:05 pm    Post subject: Reply with quote

Quote:
An M-wing takes you a long way. I am still looking for a final step that Asellus will not complain about.


Keith
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun Nov 02, 2008 8:17 pm    Post subject: Reply with quote

Code:
.---------------------------.---------------------------.---------------------------.
| 1        468      3468    | 7        9        5       | 368      2        346     |
| 567      2        35678   | 4        18       1368    | 13568    1367     9       |
| 5679     456789   3456789 | 68       2        1368    | 13568    1367     346     |
:---------------------------+---------------------------+---------------------------:
| 8        1        569     | 59       3        7       | 2        4        56      |
| 4        59       2       | 1        6        89      | 7        38       35      |
| 3        567      567     | 2        58       4       | 9        68       1       |
:---------------------------+---------------------------+---------------------------:
| 569      45689    145689  | 5689     7        1689    | 136      136      2       |
| 2        689      1689    | 3        4        1689    | 16       5        7       |
| 567      3        1567    | 56       15       2       | 4        9        8       |
'---------------------------'---------------------------'---------------------------'


I am just amazed at the 7 candidates left in r3c3
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keith



Joined: 19 Sep 2005
Posts: 3165
Location: near Detroit, Michigan, USA

PostPosted: Sun Nov 02, 2008 8:56 pm    Post subject: Reply with quote

Norm,

In your grid there is an M-wing
Quote:
58 - 59 - 89 - 59 that solves R6C5 as <5>. (It eliminates <5> in R6C23.)


Keith
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keith



Joined: 19 Sep 2005
Posts: 3165
Location: near Detroit, Michigan, USA

PostPosted: Sun Nov 02, 2008 9:21 pm    Post subject: Reply with quote

After the M-wing, I get to here:

Code:
+-------------+-------------+-------------+
| 1   46  4-8 | 7   9   5   | 68a 2   3   |
| 567 2   3   | 4   8   1   | 56  67  9   |
| 579 57  89d | 6   2   3   |15-8 17  4   |
+-------------+-------------+-------------+
| 8   1   5   | 9   3   7   | 2   4   6   |
| 4   9   2   | 1   6   8   | 7   3   5   |
| 3   67  67  | 2   5   4   | 9   8   1   |
+-------------+-------------+-------------+
| 59  45  149 | 8   7   69  | 3   16  2   |
| 2   8   19c | 3   4   69  | 16b 5   7   |
| 67  3   67  | 5   1   2   | 4   9   8   |
+-------------+-------------+-------------+

The XY-chain abcd has pincers <8>, making the eliminations shown. Done.

Keith
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun Nov 02, 2008 9:24 pm    Post subject: Reply with quote

keith wrote:
Norm,

In your grid there is an M-wing
Quote:
58 - 59 - 89 - 59 that solves R6C5 as <5>. (It eliminates <5> in R6C23.)


Keith


hi keith, I was posting the grid for those who might not have the grid after basics and yes, I see the m-wing and there is a w-wing
the w-wing has the strong link on 5 in col 9.
both will take you a long way. the next move will have to involve stringing together some of those bi-value cells (xy-chains).
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Asellus



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

PostPosted: Sun Nov 02, 2008 10:33 pm    Post subject: Reply with quote

Keith,

To me, your M-Wing looks like an XY-Wing with a moustache again.
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun Nov 02, 2008 10:38 pm    Post subject: Reply with quote

In all of my No puzzles so far, XY-Chains were available to crack the puzzles ... but were never used. Interesting that this puzzle could be reduced to 27 eliminations remaining ... and still present a problem if XY/XYZ-Wings are removed from the solving techniques.
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun Nov 02, 2008 11:04 pm    Post subject: Reply with quote

I can't get keith's M-Wing to work. So I'll supply an alternate.

Code:
M-Wing: 59-89-59-35  =>  [r4c9]<>5
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Asellus



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

PostPosted: Sun Nov 02, 2008 11:04 pm    Post subject: Reply with quote

After Norm's W-Wing, an XY chain can be avoided by, for example:
(5-8)r3c7=(8)r1c7 - (8=4)r1c3 - (4)r1c2=(4-5)r7c2=(5)r3c2 - (5)r3c7; r3c7<>5
This is basically a Medusa Trap. After this, there is a BUG+1.

Perhaps the avoidance of XY chains is because they are too much like "extended" XY Wings.
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Marty R.



Joined: 12 Feb 2006
Posts: 5159
Location: Rochester, NY, USA

PostPosted: Mon Nov 03, 2008 1:55 am    Post subject: Reply with quote

After five assorted moves, I got stuck here:

Code:

+------------+--------+----------+
| 1   46 48  | 7 9 5  | 68  2  3 |
| 567 2  3   | 4 8 1  | 56  67 9 |
| 79  57 89  | 6 2 3  | 158 17 4 |
+------------+--------+----------+
| 8   1  5   | 9 3 7  | 2   4  6 |
| 4   9  2   | 1 6 8  | 7   3  5 |
| 3   67 67  | 2 5 4  | 9   8  1 |
+------------+--------+----------+
| 59  45 149 | 8 7 69 | 3   16 2 |
| 2   8  19  | 3 4 69 | 16  5  7 |
| 67  3  67  | 5 1 2  | 4   9  8 |
+------------+--------+----------+

Play this puzzle online at the Daily Sudoku site
At this point it easily succumbs to a Medusa wrap, but I would've been happier with something else.
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keith



Joined: 19 Sep 2005
Posts: 3165
Location: near Detroit, Michigan, USA

PostPosted: Mon Nov 03, 2008 3:19 am    Post subject: Reply with quote

Asellus wrote:
Keith,

To me, your M-Wing looks like an XY-Wing with a moustache again.

And, how is that? Rolling Eyes Rolling Eyes
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keith



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PostPosted: Mon Nov 03, 2008 3:30 am    Post subject: Reply with quote

daj95376 wrote:
I can't get keith's M-Wing to work.

Why not?

Norm's grid:
Code:
.---------------------------.---------------------------.---------------------------.
| 1        468      3468    | 7        9        5       | 368      2        346     |
| 567      2        35678   | 4        18       1368    | 13568    1367     9       |
| 5679     456789   3456789 | 68       2        1368    | 13568    1367     346     |
:---------------------------+---------------------------+---------------------------:
| 8        1        569     | 59c      3        7       | 2        4        56      |
| 4        59a      2       | 1        6        89b     | 7        38       35      |
| 3       -567     -567     | 2        58d      4       | 9        68       1       |
:---------------------------+---------------------------+---------------------------:
| 569      45689    145689  | 5689     7        1689    | 136      136      2       |
| 2        689      1689    | 3        4        1689    | 16       5        7       |
| 567      3        1567    | 56       15       2       | 4        9        8       |
'---------------------------'---------------------------'---------------------------'

a and c have the same value. Strong links on <9>. Extending from c to d with a strong link on <5>, Pincers are <5> in a and d, making the eliminations shown. Leaving d as the only <5> in R6.


Last edited by keith on Mon Nov 03, 2008 3:48 am; edited 1 time in total
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keith



Joined: 19 Sep 2005
Posts: 3165
Location: near Detroit, Michigan, USA

PostPosted: Mon Nov 03, 2008 3:43 am    Post subject: Reply with quote

keith wrote:
After the M-wing, I get to here:

Code:
+-------------+-------------+-------------+
| 1   46  4-8 | 7   9   5   | 68a 2   3   |
| 567 2   3   | 4   8   1   | 56  67  9   |
| 579 57  89d | 6   2   3   |15-8 17  4   |
+-------------+-------------+-------------+
| 8   1   5   | 9   3   7   | 2   4   6   |
| 4   9   2   | 1   6   8   | 7   3   5   |
| 3   67  67  | 2   5   4   | 9   8   1   |
+-------------+-------------+-------------+
| 59  45  149 | 8   7   69  | 3   16  2   |
| 2   8   19c | 3   4   69  | 16b 5   7   |
| 67  3   67  | 5   1   2   | 4   9   8   |
+-------------+-------------+-------------+

The XY-chain abcd has pincers <8>, making the eliminations shown. Done.

Keith

And, Asellus, if you are complaining about this move: There are no XY-wings in this grid. There is an XYZ-wing, far removed from my elimination.

I can give you a 10-link chain in this grid that makes an elimination, if you think that more satisfies your intellect?

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5159
Location: Rochester, NY, USA

PostPosted: Mon Nov 03, 2008 4:52 am    Post subject: Reply with quote

keith wrote:
daj95376 wrote:
I can't get keith's M-Wing to work.

Why not?

Norm's grid:
Code:
.---------------------------.---------------------------.---------------------------.
| 1        468      3468    | 7        9        5       | 368      2        346     |
| 567      2        35678   | 4        18       1368    | 13568    1367     9       |
| 5679     456789   3456789 | 68       2        1368    | 13568    1367     346     |
:---------------------------+---------------------------+---------------------------:
| 8        1        569     | 59c      3        7       | 2        4        56      |
| 4        59a      2       | 1        6        89b     | 7        38       35      |
| 3       -567     -567     | 2        58d      4       | 9        68       1       |
:---------------------------+---------------------------+---------------------------:
| 569      45689    145689  | 5689     7        1689    | 136      136      2       |
| 2        689      1689    | 3        4        1689    | 16       5        7       |
| 567      3        1567    | 56       15       2       | 4        9        8       |
'---------------------------'---------------------------'---------------------------'

a and c have the same value. Strong links on <9>. Extending from c to d with a strong link on <5>, Pincers are <5> in a and d, making the eliminations shown. Leaving d as the only <5> in R6.

It's also a W-Wing connected by the 5s in row 6.
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keith



Joined: 19 Sep 2005
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PostPosted: Mon Nov 03, 2008 5:02 am    Post subject: Reply with quote

Question It's also a W-Wing connected by the 5s in row 6.

There is not a strong link on <5> in R6. Am I missing something, like grouped coloring?

Keith
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Marty R.



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PostPosted: Mon Nov 03, 2008 5:23 am    Post subject: Reply with quote

keith wrote:
Question It's also a W-Wing connected by the 5s in row 6.

There is not a strong link on <5> in R6. Am I missing something, like grouped coloring?

Keith

The way it was explained to me a year or so ago is that the 5 in row 6 is in either column 5 or box 1, ergo, the connection.

If this is grouped coloring or grouped strong links and I'm explaining it to you, then something's seriously wrong in this world!!
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Asellus



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

PostPosted: Mon Nov 03, 2008 7:18 am    Post subject: Reply with quote

Yes, that is a grouped strong link on <5> in r6 and it activate's the 59 W-Wing Norm already pointed out. You could also use the strong link on <5> in c9 to do so. But, that W-Wing is not Keith's M-Wing.
Keith wrote:
And, Asellus, if you are complaining about this move: There are no XY-wings in this grid. There is an XYZ-wing, far removed from my elimination.

I can give you a 10-link chain in this grid that makes an elimination, if you think that more satisfies your intellect?

I have no complaints about XY chains. Danny just mentioned that no one was using them and I suggested why they might be avoiding them. I prefer to try Medusa coloring over looking for XY chains. But, that's just me.

As for that first M-Wing, it performs exactly the same eliminations as, and includes all of the cells of, the XY-Wing in r5c26|r6c5. But, it IS an M-Wing (I can see it even if some others can't). Myself, I would reject using it, per Danny's challenge, since it is too close to the prohibited XY Wing. However I'm certainly not making the rules for these puzzles: Danny is. So, he can judge. It is a matter of indifference to me. And, it has nothing whatsoever to do with intellect!
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Asellus



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

PostPosted: Mon Nov 03, 2008 7:30 am    Post subject: Reply with quote

P.S.:

Just to show that I am not being arbitrary, take a look at the thread for "Set A Puzzle 1". nataraj used a generalized M-Wing that includes XY-Wing cells and performs the same elimination, just as the case here. And, it is Danny who objects, not me.
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Mon Nov 03, 2008 6:30 pm    Post subject: Reply with quote

keith wrote:
Why not?

Norm's grid:
Code:
.---------------------------.---------------------------.---------------------------.
| 1        468      3468    | 7        9        5       | 368      2        346     |
| 567      2        35678   | 4        18       1368    | 13568    1367     9       |
| 5679     456789   3456789 | 68       2        1368    | 13568    1367     346     |
:---------------------------+---------------------------+---------------------------:
| 8        1        569     | 59c      3        7       | 2        4        56      |
| 4        59a      2       | 1        6        89b     | 7        38       35      |
| 3       -567     -567     | 2        58d      4       | 9        68       1       |
:---------------------------+---------------------------+---------------------------:
| 569      45689    145689  | 5689     7        1689    | 136      136      2       |
| 2        689      1689    | 3        4        1689    | 16       5        7       |
| 567      3        1567    | 56       15       2       | 4        9        8       |
'---------------------------'---------------------------'---------------------------'

a and c have the same value. Strong links on <9>. Extending from c to d with a strong link on <5>, Pincers are <5> in a and d, making the eliminations shown. Leaving d as the only <5> in R6.

This is your hint to Norm for the M-Wing.

Code:
58 - 59 - 89 - 59 that solves R6C5 as <5>. (It eliminates <5> in R6C23.)

I tried to make an M-Wing out of your cells ... in the order you provided them! Later, I did manage to reverse the cell order and find your M-Wing.

BTW: In this grid, there is an XY-Wing (59a-98b-85d) that uses three of your four cells and performs the same eliminations as your M-Wing. Not a good choice given the theme of the No puzzles.
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