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1sudoku.com Evil Puzzle

 
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Sat Jul 23, 2016 12:31 am    Post subject: 1sudoku.com Evil Puzzle Reply with quote

I have a Eureka notation question for you experts about this one after the basics. Thanks, Don.
Code:

 1sudoku.net #520261 Evil

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



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

PostPosted: Sat Jul 23, 2016 1:39 pm    Post subject: Reply with quote

Are you refering to
Code:
+--------------------+-------------+----------------+
| 9     (56)  (356)  | 1   7     2 | 38    368  4   |
| 7     1     (26)   | 3   8     4 | 29    5    269 |
| 238   28    4      | 9   5     6 | 7     1    23  |
+--------------------+-------------+----------------+
| 6     3     7      | 8   49    5 | 149   2    19  |
| 258   2589  589-2  | 24  1     7 | 3459  346  369 |
| 1     4     59-2   | 6   29    3 | 59    7    8   |
+--------------------+-------------+----------------+
| 2358  258   1      | 24  234   9 | 6     348  7   |
| 23    7     (236)  | 5   2346  8 | 1234  9    123 |
| 4     2689  3689-2 | 7   236   1 | 238   38   5   |
+--------------------+-------------+----------------+
[NT(236)r128c3=5r1c3-(5=6)r1c2-(6=2)r2c3]-2r569c3; stte
or
[2r28c3==5r1c3-5r1c3==2r2c3]-2r569c3; stte


Last edited by JC Van Hay on Sat Jul 23, 2016 7:55 pm; edited 1 time in total
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Sat Jul 23, 2016 2:35 pm    Post subject: Reply with quote

Hi JC, I used the same concept but mine is not as advanced as yours. I keep forgetting about grouping expressions in square brackets - and I've never seen the double equal signs used in Eureka before! I was able to figure out the translation of your 2nd expression but I was wondering - what is the exact meaning of the double equal sign?

My chain started by assuming that r6c5=9 so r6c7=5 so r6c3=2 so r2c3=6 so r1c2=5 so r1c3=3 so r8c3<>236 contradiction. I was trying to figure out how to express this in Eureka. I seem to recall seeing an expression that you posted a long time ago that used {} to indicate a column or a cell not having any possible value. Thanks!
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bat999



Joined: 09 Jul 2015
Posts: 55
Location: UK

PostPosted: Sat Jul 23, 2016 5:44 pm    Post subject: Reply with quote

Code:
.---------------------.---------------.------------------.
| 9     d56    d356   |  1    7     2 |  38    c368  4   |
| 7      1     e26    |  3    8     4 |  29     5    269 |
| 238    28     4     |  9    5     6 |  7      1    23  |
:---------------------+---------------+------------------:
| 6      3      7     |  8   a49    5 |  149    2    19  |
| 258    2589   2589  | a24   1     7 |  3459   346  369 |
| 1      4     f259   |  6    2-9   3 | f59     7    8   |
:---------------------+---------------+------------------:
| 2358   258    1     | b24   234   9 |  6     c348  7   |
| 23     7     e236   |  5    2346  8 |  1234   9    123 |
| 4      2689   23689 |  7    236   1 |  238   c38   5   |
'---------------------'---------------'------------------'
(9=2)r4c5,r5c4 - (2=4)r7c4 - (4=6)r179c8 - (6=3)r1c23 - (3=2)r28c3 - (2=9)r6c37 => -9 r6c5; stte
Cool
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bat999



Joined: 09 Jul 2015
Posts: 55
Location: UK

PostPosted: Sat Jul 23, 2016 6:40 pm    Post subject: Reply with quote

dongrave wrote:
... assuming that r6c5=9 so r6c7=5 so r6c3=2 so r2c3=6 so r1c2=5 so r1c3=3 so r8c3<>236 contradiction. I was trying to figure out how to express this in Eureka...

Hi
Your idea is OK but it's clumsy to express in Eureka notation.

You said "If 9 is true in cell r6c5 then it will eliminate all three candidates from cell r8c3".

Now that you've found the contradiction look at it down the other end of the telescope.
Say "No matter which of the three candidates is true in cell r8c3 it will always eliminate the 9 from cell r6c5".
And construct three chains to prove it.
Code:
.---------------------.---------------.------------------.
| 9     56b    356b   | 1    7     2  |  38    368   4   |
| 7     1      26bB   | 3    8     4  |  29    5     269 |
| 238   28     4      | 9    5     6  |  7     1     23  |
:---------------------+---------------+------------------:
| 6     3      7      | 8    49    5  |  149   2     19  |
| 258   2589   2589   | 24   1     7  |  3459  346   369 |
| 1     4     b259cC  | 6    2-9   3  | b59cC  7     8   |
:---------------------+---------------+------------------:
| 2358  258    1      | 24   234   9  |  6     348   7   |
| 23    7     a236aA  | 5    2346  8  |  1234  9     123 |
| 4     2689   23689  | 7    236   1  |  238   38c   5   |
'---------------------'---------------'------------------'
(2)r8c3 - (2=9)r6c37 - (9)r6c5
(3)r8c3 - (3=2)r1c23,r2c3 - (2=9)r6c37 - (9)r6c5
(6)r8c3 - (6=2)r2c3 - (2=9)r6c37 - (9)r6c5
=> -9 r6c5; stte
Cool
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JC Van Hay



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

PostPosted: Sat Jul 23, 2016 7:53 pm    Post subject: Reply with quote

Hi dongrave, r8c3={} doesn't depend on r6c57 but on the hypothesis r6c3=2. Therefore, you only have to concentrate on the 4 cells r1c2,r128c3 as I did.

Note :
The double equal sign == is used in the case of a derived strong link. In the simplest case of derived strong links from ALS, some players would have written the chain as
(2=356)r128c3-(5=26)r1c2,r2c3 -> -2r569c3
or
(2=5)r128c3-(5=2)r1c3,r2c3 -> -2r569c3.
I let you decide which notation is clearer Very Happy
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Sat Jul 23, 2016 8:16 pm    Post subject: Reply with quote

Thanks for your help guys! I'm going to go print out your postings and study it until it sinks in! Don.
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Clement



Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania

PostPosted: Mon Jul 25, 2016 11:27 pm    Post subject: 1sudoku.com Evil Puzzle Reply with quote

Code:

+-----------------+-----------+--------------+
| 9    c56   b56-3   | 1  7    2 | 38   368 4   |
| 7    1    26    | 3  8    4 | 29   5   269 |
| a238  d28   4     | 9  5    6 | 7    1   23  |
+-----------------+-----------+--------------+
| 6    3    7     | 8  g49   5 | 149  2   f19  |
| i258  id2589 i2589  | h24 1    7 | 3459 346 369 |
| 1    4    j259   | 6  29   3 | 59   7   8   |
+-----------------+-----------+--------------+
| 258-3 d258  1     | 24 234  9 | 6    348 7   |
| e2-3   7    ke236   | 5  2346 8 | 1234 9   e123 |
| 4    d2689 23689 | 7  236  1 | 238  38  5   |
+-----------------+-----------+--------------+

(3)r3c1= (3-5)r1c3 = r1c2 - (5=6*)r3579c2 - (6-1)r8c139 - (1=9)r4c9 - (9=4)r4c5 - (4=2)r5c4 - r5c123 = (2*)r6c3 - (2*6*=3)r8c3 => -3 r1c3, r78c1; stte
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