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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Mon Oct 13, 2008 10:57 pm    Post subject: ... and ?? sink Reply with quote

Code:
+-------+-------+-------+
| . . 1 | . 2 . | 3 . . |
| . 2 . | . 4 . | . 5 . |
| 6 . . | 3 . 7 | . . 1 |
+-------+-------+-------+
| . . 8 | . . . | 5 . . |
| 2 7 . | . . . | . 4 8 |
| . . 4 | . . . | 1 . . |
+-------+-------+-------+
| 8 . . | 2 . 9 | . . 5 |
| . 5 . | . 8 . | . 1 . |
| . . 2 | . 7 . | 8 . . |
+-------+-------+-------+SE 6.8 by JPF


Code:
.------------------------.------------------------.------------------------.
| 4579    489     1      | 569     2       56     | 3       789     479    |
| 379     2       379    | 18      4       18     | 679     5       679    |
| 6       48      59     | 3       59      7      | 24      28      1      |
:------------------------+------------------------+------------------------:
| 139     1369    8      | 47      369     24     | 5       23679   23679  |
| 2       7       3569   | 1569    13569   1356   | 69      4       8      |
| 359     369     4      | 78      3569    28     | 1       23679   23679  |
:------------------------+------------------------+------------------------:
| 8       1346    367    | 2       136     9      | 467     367     5      |
| 3479    5       3679   | 46      8       346    | 24679   1       234679 |
| 1349    13469   2      | 1456    7       13456  | 8       369     3469   |
'------------------------'------------------------'------------------------'SE 6.8


a puzzle from the patterns game. definitely one for a lazy afternoon without anything else to do... oh yeah and start early in the afternoon. make sure and schedule breaks for eating, etc. Laughing
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nataraj



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

PostPosted: Tue Oct 14, 2008 6:25 am    Post subject: Reply with quote

This puzzle is like a hike in the mountains - with steep ascent, dangerous narrow passages, and long stretches without water ...

After an initial coloring elimination, which removed 5 from r3c5, the clutter of candidates was reduced considerably, and after a UR (56) type 4, which removed 6 from r9c46, another almost-UR (79) pointed to a x-wing (9). This is where I started looking for more coloring and/or m/w-wings:

Code:

+--------------------------+--------------------------+--------------------------+
| 479     489     1        | 56      2       56       | 3       789     479      |
| 3       2       79       | 1       4       8        | 79      5       6        |
| 6       48      5        | 3       9       7        | 24      28      1        |
+--------------------------+--------------------------+--------------------------+
| 19      169     8        | 7       36      4        | 5       239     239      |
| 2       7       3        | 9       5       1        | 6       4       8        |
| 5       69      4        | 8       36      2        | 1       379     379      |
+--------------------------+--------------------------+--------------------------+
| 8       34      6        | 2       1       9        | 47      37      5        |
| 47      5       79       | 46      8       36       | 249     1       234      |
| 149     1349    2        | 45      7       35       | 8       6       349      |
+--------------------------+--------------------------+--------------------------+


There is now an x-wing (4) in rows 3 and 7, and with 4 gone from r1c2, an xyz-wing 89-789-79.

Now 9 is gone from r1c9 and there is a m-wing (7) r1c9=r2c7 via the strong link on (4) in col 7:
Code:

+--------------------------+--------------------------+--------------------------+
| 479     89      1        | 56      2       56       | 3      -789     47*      |
| 3       2       79       | 1       4       8        | 79      5       6        |
| 6       48      5        | 3       9       7        | 24#     28      1        |
+--------------------------+--------------------------+--------------------------+
| 19      169     8        | 7       36      4        | 5       239     239      |
| 2       7       3        | 9       5       1        | 6       4       8        |
| 5       69      4        | 8       36      2        | 1       379     379      |
+--------------------------+--------------------------+--------------------------+
| 8       34      6        | 2       1       9        | 47#     37*     5        |
| 47      5       79       | 46      8       36       | 29      1       234      |
| 149     139     2        | 45      7       35       | 8       6       349      |
+--------------------------+--------------------------+--------------------------+


A bit of cleanup, another UR type 4 (19), and coloring on 9 leads to another m-wing situation:
Code:

+--------------------------+--------------------------+--------------------------+
| 47      89      1        | 56      2       56       | 3       89#     4-7      |
| 3       2       79       | 1       4       8        | 79*     5       6        |
| 6       48      5        | 3       9       7        | 24      28      1        |
+--------------------------+--------------------------+--------------------------+
| 19      16      8        | 7       36      4        | 5       23      239      |
| 2       7       3        | 9       5       1        | 6       4       8        |
| 5       69      4        | 8       36      2        | 1       379#    37a      |
+--------------------------+--------------------------+--------------------------+
| 8       34      6        | 2       1       9        | 4-7     37b     5        |
| 47      5       79       | 46      8       36       | 29      1       234      |
| 19      13      2        | 45      7       35       | 8       6       349      |
+--------------------------+--------------------------+--------------------------+


Two overlapping m-wings (7) r2c7=r6c9 (a) and (7) r2c7=r7c8 (b), both via sl on (9) in col 8, eliminate 7 from r7c7 and r1c9, resp. and finally solve the puzzle.
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Tue Oct 14, 2008 8:35 pm    Post subject: Reply with quote

I am happy, that another one of the solvers community appreciates the Pattern Games thread. In industry the quality, they bring for free, would be paid very good - but bad qualiity 10 times better Smile
This puzzle is well selected. I did not make notes, but i think, i used 8 advanced methods, including the 19 UR (deleting 2 9's) and a 4-cell xy-chain (generalized, extended, grouped ?? xy-wing).

There is only a small way between addiction and fun, and i used to miss it Smile
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Tue Oct 14, 2008 8:50 pm    Post subject: Reply with quote

Did anyone else find the hidden quad?

excellent puzzle Shocked .... I am still trying to simplify it but can't.
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Tue Oct 14, 2008 10:07 pm    Post subject: Reply with quote

Not an easy puzzle ... even for my solver with my assistance.

Code:
Hidden Quad
X-  Wing (4)
Kite/ER  (5)
X-  Wing (9)
XY -Wing (76-47-46)
XYZ-Wing (89-789-79)

 (19) UR [r49c12] => [r6c9],[r9c2]<>9   (my assistance)
 +-----------------------------------------------------+
 |  479  89   1    |  56   2    56   |  3    789  47   |
 |  3    2    79   |  1    4    8    |  79   5    6    |
 |  6    48   5    |  3    9    7    |  24   28   1    |
 |-----------------+-----------------+-----------------|
 |  19   19+6 8    |  7    36   4    |  5    239  239  |
 |  2    7    3    |  9    5    1    |  6    4    8    |
 |  5    69   4    |  8    36   2    |  1    379  379  |
 |-----------------+-----------------+-----------------|
 |  8    34   6    |  2    1    9    |  47   37   5    |
 |  47   5    79   |  46   8    36   |  29   1    234  |
 |  19+4 19+3 2    |  45   7    35   |  8    6    349  |
 +-----------------------------------------------------+

XY-Chain -4r1c9  7r1c9  3r6c9  6r6c5  9r6c2  8r1c2  4r3c2  =>  [r1c1],[r3c7]<>4

Explanation of (19) UR [r49c12]:

Code:
[r4c2]= 6 =>                             [r6c2]=9 => [r6c9],[r9c2]<>9
[r4c2]<>6 => UR Type 3 => [r9c9]<>345 => [r9c9]=9 => [r6c9],[r9c2]<>9

Note: If ronk is following this forum, he'll be blown away to see that I finally learned to spot a UR Type 3.

[Edit: corrected a typo in XYZ-Wing during first transcription.]


Last edited by daj95376 on Wed Oct 15, 2008 3:16 am; edited 1 time in total
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Oct 14, 2008 11:00 pm    Post subject: Reply with quote

Quote:
I am happy, that another one of the solvers community appreciates the Pattern Games thread


Ravel,

it wasn't until you mentioned them that I took notice. so I went through a good hundred of them and determined most of the 6.7 - 6.9 are the most fun. in fact the patterns game is notorious for providing puzzles in which the first step, out of the gate, is difficult.

and... for the 6.7 - 6.9 ratings,

if the first step is not difficult then the puzzle requires an endless assault of these well known techniques.

having said all that, I still have an affinity for the puzzles that I can blast in one step. go figure. therefore I find it all the more fascnating that a puzzle like the one above requires all that it does.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Nov 11, 2008 1:18 am    Post subject: Reply with quote

Code:

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

Play this puzzle online

Code:

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

Play this puzzle online

the solution paths are so close that they had to be put together. the links will load them into draw/play...even with draw/play help, they will prove formidable. and to give proper credit, the top was posted by m_b_metcalf and is 6.9 SE. and the bottom by Mauricio is 6.8 SE.
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Tue Nov 11, 2008 2:18 am    Post subject: Reply with quote

The bottom one:
Code:
 *-----------------------------------------------------------------------------*
 | 4789    789     1       | 2       35679   5678    | 345789  345689  3789    |
 | 2789    3       2689    | 6789    5679    4       | 1       5689    789     |
 | 5       789    *4689    | 36789   13679   1678    |*34789   2       3789    |
 |-------------------------+-------------------------+-------------------------|
 | 6       1289    2389    | 5      *1249    128     |*23489   7       12389   |
 | 123789  125789  23589   | 4789    12479   1278    | 23489   13489   6       |
 | 12789   4       289     | 6789    12679   3       | 289     189     5       |
 |-------------------------+-------------------------+-------------------------|
 | 12389   6       23589   | 37      2357    257     | 235789  13589   4       |
 |#23489   2589    7       | 1      *23456   256     | 23589   3589    2389    |
 | 1234    125     235-4   | 347     8       9       | 6       135     1237    |
 *-----------------------------------------------------------------------------*
finned swordfish
later after a kite
 *-----------------------------------------------------------*
 | 89    7     1     | 2     39    5     | 4     6     389   |
 | 2     3     6     |#789  #79    4     | 1     5     89    |
 | 5     89    4     | 389   6     1     | 7     2     389   |
 |-------------------+-------------------+-------------------|
 | 6     2     39    | 5     4     8     | 39    7     1     |
 | 38    1     5     |#79  #*279  *27    | 38    4     6     |
 | 7     4     89    | 6     1     3     | 2     89    5     |
 |-------------------+-------------------+-------------------|
 | 1389  6     38    | 37   *2357 *27    | 59    1389  4     |
 | 4     89    7     | 1     35    6     | 589   389   2     |
 | 13    5     2     | 4     8     9     | 6     13    7     |
 *-----------------------------------------------------------*
Overlapping ur's
if r2c5=9 then 27's are a DP => r2c5=7 =>r5c4=7

I will tackle the top tomorrow Very Happy
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Tue Nov 11, 2008 8:14 am    Post subject: Reply with quote

Here is the top one:
Code:
 *-----------------------------------------------------------------------------*
 | 4689    679     1       | 2       56789   35679   | 35789   345789  4589    |
 | 689     3       678     | 1789    156789  4       | 2       5789    1589    |
 | 5       279    *2478    | 13789   1789    1379    | 13789   6      *1489    |
 |-------------------------+-------------------------+-------------------------|
 | 7       269     2368    | 5       2469    369     | 689     1      *4689    |
 | 13689   1569    3568    | 13479  *14679   13679   | 56789   45789   2       |
 | 1269    4       256     | 179     12679   8       | 5679    579     3       |
 |-------------------------+-------------------------+-------------------------|
 | 12346   8       2356-4  | 149     1459    159     | 13569   2359    7       |
 |#1234    1257    9       | 6      *14578   157     | 1358    2358    158     |
 | 16      1567    567     | 1789    3       2       | 4       589     15689   |
 *-----------------------------------------------------------------------------*
finned swordfish
 *-----------------------------------------------------------*
 | 8     67    1     | 2     569   569   | 79    3     4     |
 | 9     3     67    | 18    16    4     | 2    *78    5     |
 | 5     2     4     | 3     789  *79    | 1     6    *89    |
 |-------------------+-------------------+-------------------|
 | 7     9     2     | 5     4     3     | 8     1     6     |
 | 3     15    8     | 179   1679  1679  | 579   4     2     |
 | 16    4     56    | 179   2     8     | 579  *79    3     |
 |-------------------+-------------------+-------------------|
 | 2     8     3     | 4     19-5  19-5  | 6    *59    7     |
 | 4     157   9     | 6     578  *57    | 3     2     18    |
 | 16    167   57    | 789   3     2     | 4     589   19    |
 *-----------------------------------------------------------*
xy-chain


on both --getting started was tough-- Very Happy
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nataraj



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

PostPosted: Tue Nov 11, 2008 9:15 am    Post subject: Reply with quote

I start with the top one.

To get things going, multi-coloring (4) sets r3c3=4. This is one of the rarer instances where the discontinuity in a nice loop has two strong links:
Code:

+·····+·····+·····+
·*    ·     ·  * o·
· \   ·     ·  |  ·
·  \  ·     ·  |  ·
·   \ ·     ·  |  ·
·    *-----------*·
+····|+·····+··|··+
·    |·  *-------*·
·    |·     ·  |/ ·
·    |·* o  ·  *  ·
·    |·|    ·     ·
·    |·|    ·     ·
+····|+|····+·····+
·o   *·* o  ·     ·
·     ·     ·     ·
·*-------*  ·     ·
·     ·     ·     ·
·     ·     ·     ·
+·····+·····+·····+

(4) =r3c3=r7c3-r7c4=r5c4-r4c5=r4c9-r3c9=r3c3=;r3c3=4

Now we can proceed with the usual basics, until a UR (89) /w sl 8 becomes visible, but at the same time is destroyed by two x-wings (8) in this position:
Code:

+--------------------------+--------------------------+--------------------------+
| 89      67      1        | 2       5689    569      | 579     3       4        |
| 89      3       67       | 189     15689   4        | 2       5789    589      |
| 5       2       4        | 3       789     79       | 1       6       89       |
+--------------------------+--------------------------+--------------------------+
| 7       9       2        | 5       4       3        | 8       1       6        |
| 3       15      8        | 179     1679    1679     | 579     4       2        |
| 16      4       56       | 179     2       8        | 579     579     3        |
+--------------------------+--------------------------+--------------------------+
| 2       8       3        | 4       159     159      | 6       59      7        |
| 4       157     9        | 6       578     57       | 3       2       158      |
| 16      1567    567      | 789     3       2        | 4       589     1589     |
+--------------------------+--------------------------+--------------------------+

After cleaning up, here
Code:
+--------------------------+--------------------------+--------------------------+
| 8       67      1        | 2       569     569      | 79      3       4        |
| 9       3       67       | 18      16*     4        | 2       78      5        |
| 5       2       4        | 3       789     79       | 1       6       89       |
+--------------------------+--------------------------+--------------------------+
| 7       9       2        | 5       4       3        | 8       1       6        |
| 3       15      8        | 179     1679#   1679#    | 579     4       2        |
| 16      4       56       | 179     2       8        | 579     79      3        |
+--------------------------+--------------------------+--------------------------+
| 2       8       3        | 4      -159     159*     | 6       59      7        |
| 4       157     9        | 6       578     57       | 3       2       18       |
| 16      1567    567      | 789     3       2        | 4       589     19       |
+--------------------------+--------------------------+--------------------------+

a generalized m-wing (1)r2c5=r7c6 via SL (6) in row 5 (and I do hope it's not one of these Groucho Marx xy-wings in disguise!)

Kite (9) row 7, col 9 removes 9 from r3c5, and a short while later, an xy-wing (59-57-79 col 6, box 8: r1c5<>9) is essential.

The next vh+ step takes a useless gm-wing and transports it:


Code:

+--------------------------+--------------------------+--------------------------+
| 8       67      1        | 2       56      569#     | 79#     3       4        |
| 9       3       67       | 18      16      4        | 2       78      5        |
| 5       2       4        | 3       78      79       | 1       6       89       |
+--------------------------+--------------------------+--------------------------+
| 7       9       2        | 5       4       3        | 8       1       6        |
| 3       15      8        | 179     1679    67       | 579t    4       2        |
| 16      4       56       | 179     2       8        | 579t    79*     3        |
+--------------------------+--------------------------+--------------------------+
| 2       8       3        | 4       59#     1        | 6       59t     7        |
| 4       157     9        | 6       578     57#      | 3       2       18       |
| 16      1567    567      | 789     3       2        | 4       589t    19**     |
+--------------------------+--------------------------+--------------------------+

The m-wing is (9)r7c5=r1c7 via SL (5) in row 1 or col 6 (marked #-#-#-#).
The r1c7 end can be transported via box 6 (-r56c7=r6c8) to r6c8 (marked *.This means r7c8<>9)
and on via box 9 (-r79c8=r9c9) to r9c9 (marked **. This means r9c4<>9)

Not done yet.
An xy-wing (78-89-79 row 9, col 8) and another one (16-17-67 box 7 col 2) finally crack this nut.
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nataraj



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

PostPosted: Tue Nov 11, 2008 9:21 am    Post subject: Reply with quote

Oy, oy. dan beat me by more than an hour! And a much shorter solution, too...

All I can say is I tried to do it without xy-wings or chains. Didn't succed on the xy-wings...
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Nov 11, 2008 7:15 pm    Post subject: Reply with quote

nataraj, sorry to see you tried skipping the common wings. the thrust of this thread was to show just how difficult puzzles can be if you use common wings (x-xy-xyz), simple/multicoloring, UR's, xy-chains. hopefully, this will be inviting to the casual observer since I am looking for puzzles that only require these techniques. in fact, the only diffrence from what Danny is doing is I am purposefully looking for the long VH solution paths. m-wings and w-wings in these puzzles are easter eggs and bonuses much like they are in the VH puzzles on this site.
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nataraj



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

PostPosted: Tue Nov 11, 2008 7:52 pm    Post subject: Reply with quote

no prob, Norm. I wasn't trying too hard, anyway, and I wasn't skipping (only delaying) and not the "common" wings but only the xy-wing.

My search pattern has changed over the last few months and I tend to look for xy-wings much later than I used to before (except in the "daily" vh's, but that is only because I know that usually there is one xy-wing that solves the thing). That's about the same time when Danny started his "no" series and got me going on that "no xy" path Smile

So when all of UR, coloring, (un-finned) fish and m/w wings (including the recently approved Detroit wing Laughing) leave me empty handed, I still go looking for xy-wings. I do avoid the (mostly) random and/or tedious search for xy-chains - I'll gladly leave that task to computers ...


Last edited by nataraj on Tue Nov 11, 2008 8:13 pm; edited 1 time in total
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Tue Nov 11, 2008 8:04 pm    Post subject: Reply with quote

I started off brilliantly with an ER on <5> that left an x-wing on <5> and a quad in Box5. Then another x-wing - a Type 4 UR - an ER on <7> - and an xyz wing. But that's all Folks. A plethora of pairs and nothing to show for it.

Last edited by cgordon on Tue Nov 11, 2008 8:05 pm; edited 1 time in total
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Nov 11, 2008 8:04 pm    Post subject: Reply with quote

Quote:
I tend to look for xy-wings much later than I used to


and this only makes sense since bi-value cells are hard to find at the bigginning stages of a puzzle (which might actually make it easier to find a "naked" xy-wing"). where as, in the latter stages of a puzzle there is a bunch of bi-value cells (which might make it harder to find "hidden" xy-wings, go figure). now that I think about it, I have seen many puzzles where an xy-wing or xy-chain was the finishing move. makes sense.
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nataraj



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

PostPosted: Tue Nov 11, 2008 8:52 pm    Post subject: Reply with quote

Order to chaos (and back?)

Many of my (RL) friends like to solve sudoku. One thing I've learned: everybody does it differently. Same here, it seems. This thread got me to reflect on how I go about solving those vh-plus-es and how this process might be much more psychologically determined than rationally.

It all starts very orderly: a few clues on the grid. Sweeping the floors, dusting the towers. Many solved cells, a few "potential marks", almost no PMs.

This phase lasts for 2,3 maybe 4 minutes. (such a short pleasure!)

Looking at houses with 7 or 6 solved cells first, then moving down to those with 5,4,3 or -god forbid- only two solved cells. Pencil marks grow longer and longer. Clutter galore.

Fifteen to twenty minutes into the puzzle, there is no more order, but pure chaos. "done with basics". Hm...

What now?

If it is a dailysudoku.com "vh" puzzle, I scan for xy-wings.

Otherwise I start looking for strong links in individual candidates (1,2,...). I draw my little "nataraj" diagrams, I find x-wings, kites, fish, m-wings, w-wings. Actually, what I realized today is that at this point I stop looking at the puzzle per se - because there is too much chaos and too little structure in the whole grid! I "distill" information from the grid and I use that information to find relationships between cells.

So, in a sense, I have managed to go back from chaos to order, from a clutter of pencil marks to a clean (albeit two-dimensional) world of strong and weak links.

Here's where my aversion to xy-wings / -chains comes in: that would force me to go back and look for connected cells directly in the grid.

Funny that I don't mind checking for UR's - maybe the identical bi-values are so easy to spot, that they again qualify as "order" ?
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Tue Nov 11, 2008 10:43 pm    Post subject: Reply with quote

Initial PMs and non-fish logic for (4):

Code:
Either (a) is true or else (bbb) is true.
If (bbb) is true, then (cc) is true.
If (cc) is true, then (4) is completely eliminated in [b5].
Thus, (a) is true.

Code:
 first puzzle: [r3c3]=4
 *-----------------------------------------------------------------------------*
 |b4689    679     1       | 2       56789   35679   | 35789   345789  4589    |
 | 689     3       678     | 1789    156789  4       | 2       5789    1589    |
 | 5       279    a2478    | 13789   1789    1379    | 13789   6      b1489    |
 |-------------------------+-------------------------+-------------------------|
 | 7       269     2368    | 5       2469    369     | 689     1       4689    |
 | 13689   1569    3568    | 13479   14679   13679   | 56789  c45789   2       |
 | 1269    4       256     | 179     12679   8       | 5679    579     3       |
 |-------------------------+-------------------------+-------------------------|
 | 12346   8      b23456   | 149     1459    159     | 13569   2359    7       |
 | 1234    1257    9       | 6      c14578   157     | 1358    2358    158     |
 | 16      1567    567     | 1789    3       2       | 4       589     15689   |
 *-----------------------------------------------------------------------------*

Code:
 second puzzle: [r3c3]=4
 *-----------------------------------------------------------------------------*
 |b4789    789     1       | 2       35679   5678    | 345789  345689  3789    |
 | 2789    3       2689    | 6789    5679    4       | 1       5689    789     |
 | 5       789    a4689    | 36789   13679   1678    |b34789   2       3789    |
 |-------------------------+-------------------------+-------------------------|
 | 6       1289    2389    | 5       1249    128     | 23489   7       12389   |
 | 123789  125789  23589   | 4789    12479   1278    | 23489  c13489   6       |
 | 12789   4       289     | 6789    12679   3       | 289     189     5       |
 |-------------------------+-------------------------+-------------------------|
 | 12389   6       23589   | 37      2357    257     | 235789  13589   4       |
 | 23489   2589    7       | 1      c23456   256     | 23589   3589    2389    |
 | 1234    125    b2345    | 347     8       9       | 6       135     1237    |
 *-----------------------------------------------------------------------------*
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Asellus



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

PostPosted: Wed Nov 12, 2008 7:52 am    Post subject: Reply with quote

daj95376 wrote:
non-fish logic for (4)

I'd call it ER logic. In both cases, there is a conjugate pair of <4>s in r8. The <4> in r1c1 sees the <4> in r8c1 directly and sees the <4> in r8c5 via the sequence of ERs in b5, b6 and b3. Thus, r1c1<>4.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Thu Nov 13, 2008 6:15 am    Post subject: Reply with quote

it has it all.
Code:

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

Play this puzzle online at the Daily Sudoku site

Code:
.---------------------.---------------------.---------------------.
| 237    127    9     | 6      237    5     | 278    48     124   |
| 2367   4      236   | 8      237    1     | 5      9      26    |
| 8      16     5     | 4      9      27    | 27     3      16    |
:---------------------+---------------------+---------------------:
| 1      67     3468  | 9      68     37    | 34     2      5     |
| 23469  269    23468 | 5      68     23    | 349    1      7     |
| 2379   5      23    | 1      27     4     | 39     6      8     |
:---------------------+---------------------+---------------------:
| 25     3      1     | 7      4      6     | 28     58     9     |
| 45     8      7     | 2      1      9     | 6      45     3     |
| 2469   269    246   | 3      5      8     | 1      7      24    |
'---------------------'---------------------'---------------------'
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nataraj



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

PostPosted: Thu Nov 13, 2008 7:13 am    Post subject: Reply with quote

Has it "all"?

I must have taken the easy way.
one x-wing (7) to remove 7 from r1c1 and r1c5.
coloring (2) to solve the puzzle.
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