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keith



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

PostPosted: Sun Mar 18, 2012 1:30 pm    Post subject: Interesting ... Reply with quote

This from my Saturday newspaper, labelled "Universal Sudoku Puzzle". I have not before seen these puzzles require advanced moves.
Code:
Puzzle: AD20120317
+-------+-------+-------+
| 9 4 1 | 7 . . | . . 8 |
| . 2 . | . . 6 | . . 7 |
| 7 . 6 | 1 . . | . . 3 |
+-------+-------+-------+
| . . 7 | . . 5 | . . 4 |
| . . . | . . . | . . . |
| 8 . . | 9 . . | 2 . . |
+-------+-------+-------+
| 4 . . | . . 9 | 3 . 6 |
| 3 . . | 5 . . | . 4 . |
| 6 . . | . . 8 | 7 5 9 |
+-------+-------+-------+
Keith
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Auburnmom



Joined: 13 Mar 2008
Posts: 25
Location: Auburn, AL

PostPosted: Sun Mar 18, 2012 2:20 pm    Post subject: Reply with quote

I also have this puzzle and am stopped. So I am sure there is a step that is beyond my ability.

[/img]
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sun Mar 18, 2012 4:41 pm    Post subject: Reply with quote

Given Keith's comments, I did not pursue non-advanced moves but found three views of the same deletions.

After basics:
Code:
*-----------------------------------------------------------------------------*
 | 9       4       1       | 7       235     23      | 56      26      8       |
 | 5       2       3       | 48      489     6       | 149     19      7       |
 | 7       8       6       | 1       2459    24      | 459     29      3       |
 |-------------------------+-------------------------+-------------------------|
 | 12      369     7       | 368     12      5       | 689     3689    4       |
 | 12      3569    459     | 3468    123478  12347   | 689     36789   15      |
 | 8       356     45      | 9       1347    1347    | 2       367     15      |
 |-------------------------+-------------------------+-------------------------|
 | 4       57      58      | 2       17      9       | 3       18      6       |
 | 3       79      89      | 5       6       17      | 18      4       2       |
 | 6       1       2       | 34      34      8       | 7       5       9       |
 *-----------------------------------------------------------------------------*

almost xy-wing (24-9)[r3c68+r2c5]=(8)r2c5-(8=4)r2c4-(4=2)r3c6-(2=9)r3c8; r2c78, r3c5<>9
or
anp(9=48)r2c54-(4=2)r3c6-(2=9)r3c8; r2c78, r3c5<>9
or
ALS XZ; r2c78, r3c5<>9
a=(489)r2c45
b=(249)r3c68
x=4
z=9

Ted
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Sun Mar 18, 2012 5:01 pm    Post subject: Reply with quote

Code:
After 8 singles

+---------------+---------------------+--------------------+
| 9   4     1   | 7     235     23    | 56      26      8  |
| 5   2     3   | 48    8-4(9)  6     | -9(14)  -9(1)   7  |
| 7   8     6   | 1     24(59)  24    | 9(45)   29      3  |
+---------------+---------------------+--------------------+
| 12  369   7   | 368   1238    5     | 1689    13689   4  |
| 12  3569  459 | 3468  123478  12347 | 15689   136789  15 |
| 8   356   45  | 9     1347    1347  | 2       1367    15 |
+---------------+---------------------+--------------------+
| 4   57    58  | 2     17      9     | 3       18      6  |
| 3   79    89  | 5     6       17    | 18      4       2  |
| 6   1     2   | 34    34      8     | 7       5       9  |
+---------------+---------------------+--------------------+

4-SIS AIC : 9r2c5=(9-5)r3c5=(5-4)r3c7=(4-1)r2c7=1r2c8 => -4r2c5, -9r2c78; stte
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Marty R.



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

PostPosted: Sun Mar 18, 2012 5:12 pm    Post subject: Reply with quote

Code:
*-----------------------------------------------------------------------------*
 | 9       4       1       | 7       235     23      | 56      26      8       |
 | 5       2       3       | 48      489     6       | 149     19      7       |
 | 7       8       6       | 1       2459    24      | 459     29      3       |
 |-------------------------+-------------------------+-------------------------|
 | 12      369     7       | 368     12      5       | 689     3689    4       |
 | 12      3569    459     | 3468    123478  12347   | 689     36789   15      |
 | 8       356     45      | 9       1347    1347    | 2       367     15      |
 |-------------------------+-------------------------+-------------------------|
 | 4       57      58      | 2       17      9       | 3       18      6       |
 | 3       79      89      | 5       6       17      | 18      4       2       |
 | 6       1       2       | 34      34      8       | 7       5       9       |
 *-----------------------------------------------------------------------------*


I don't know if mine is similar as JC's due to my Eureka deficiencies. But in a short AIC, r3c8=2 proves r2c5=9; r2c78, r3c5<>9.
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Sun Mar 18, 2012 6:00 pm    Post subject: Reply with quote

Marty,

What was exactly your path ? ...

Furthermore, you only need "r3c8=2 proves r3c5=5" to get r3c5<>9 Exclamation

In Eureka, among a lot of other possibilities as Ted showed :

    (9=2)r3c8-AHP[2r1c8=23r1c56]-5r1c5=5r3c5 => -9r3c5
    or
    (9=2)r3c8-(2=6)r1c8-(6=5)r1c7-5r1c5=5r3c5 => -9r3c5
    or
    ...
Regards, JC.
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Marty R.



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

PostPosted: Sun Mar 18, 2012 6:48 pm    Post subject: Reply with quote

Path:

Code:
*----------------------------------------------------------------------------------*
 | 9       4       1       |  7        235      23      | 56       26      8       |
 | 5       2       3       | C48      D489      6       | 149      19      7       |
 | 7       8       6       |  1        2459    B24      | 459     A29      3       |
 |-------------------------+---------- -----------------+--------------------------|
 | 12      369     7       |  368      12       5       | 689      3689    4       |
 | 12      3569    459     |  3468     123478   12347   | 689      36789   15      |
 | 8       356     45      |  9        1347     1347    | 2        367     15      |
 |-------------------------+----------------------------+--------------------------|
 | 4       57      58      |  2        17       9       | 3        18      6       |
 | 3       79      89      |  5        6        17      | 18       4       2       |
 | 6       1       2       |  34       34       8       | 7        5       9       |
 *---------------------------------------------------------------------------------*


I can follow how the 2 proves the 5 but that's probably not the kind of thing I'd notice.
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arkietech



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

PostPosted: Sun Mar 18, 2012 7:16 pm    Post subject: Reply with quote

I got the same as Ted Very Happy

Code:
 *-----------------------------------------------------------------------------*
 | 9       4       1       | 7      d235     23      |c56     b26      8       |
 | 5       2       3       | 48      489     6       | 149     19      7       |
 | 7       8       6       | 1      e245-9   24      | 459    a29      3       |
 |-------------------------+-------------------------+-------------------------|
 | 12      369     7       | 368     12      5       | 689     3689    4       |
 | 12      3569    459     | 3468    123478  12347   | 689     36789   15      |
 | 8       356     45      | 9       1347    1347    | 2       367     15      |
 |-------------------------+-------------------------+-------------------------|
 | 4       57      58      | 2       17      9       | 3       18      6       |
 | 3       79      89      | 5       6       17      | 18      4       2       |
 | 6       1       2       | 34      34      8       | 7       5       9       |
 *-----------------------------------------------------------------------------*
 xy-wing with extension???
(9=2)r3c8-(2=6)r1c8-(6=5)r1c7-(5)r1c5=(5)r3c5 => r1c5<>9
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Sun Mar 18, 2012 7:43 pm    Post subject: Reply with quote

Marty,

OK, now I understand your logic.

In a word, you are using the same SIS as Ted who gave 3 different interpretations of the same deletions.

In Eureka, I am reading your path as

4-SIS t-Chain : (9=2)r3c8-(2=4)r3c6-(4=8)r2c4-(84#2=9)r2c5 => -9r3c5, -9r2c78

That is :

Either r3c8=9; Or r3c8=2, r3c6<>2, r3c6=4, r2c4<>4, r2c4=8, [r2c5<>8 and r2c5<>4(because of r3c6=4)], r2c5=9
=> pincers (9r3c8,9r2c5) => r3c5<>9 and r2c78<>9

Thanks a lot for the clarifications.

Regards, JC
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arkietech



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

PostPosted: Sun Mar 18, 2012 10:30 pm    Post subject: Reply with quote

JC Van Hay wrote:
(9=2)r3c8-(2=4)r3c6-(4=8)r2c4-(84#2=9)r2c5 => -9r3c5, -9r2c78
wouldn't

(9=2)r3c8-(2=4)r3c6-(48=9)r2c45 => -9r3c5, -9r2c78

be better?
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Mon Mar 19, 2012 8:16 pm    Post subject: Reply with quote

Dan,

Of course, it's better to write (9=2)r3c8-(2=4)r3c6-(4=89)r2c45 => -9r3c5, -9r2c78.

However, in my previous post, I hoped to translate Marty's logic as faithfully as possible.
Therfore, my "detailed" presentation.

Regards, JC.
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