November 18, 2017

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November 18, 2017

Postby ArkieTech » Sat Nov 18, 2017 12:05 am

Code: Select all
 *-----------*
 |...|...|...|
 |...|.9.|...|
 |..8|6.1|7..|
 |---+---+---|
 |.5.|...|.6.|
 |2..|...|..1|
 |.6.|3.7|.9.|
 |---+---+---|
 |..7|...|8..|
 |..9|.3.|1..|
 |.1.|.5.|.2.|
 *-----------*


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Re: November 18, 2017

Postby Leren » Sat Nov 18, 2017 12:27 am

Code: Select all
*--------------------------------------------*
| 16 34 25  | 248  7   35 |ka246-9 18   2349 |
| 16 7  25  | 248  9   35 | j246   18   234  |
| 9  34 8   | 6   e24  1  |  7     345 d2345 |
|-----------+-------------+------------------|
| 7  5  134 | 249  124 49 | h234   6    8    |
| 2  9  34  | 5    8   6  |  34    7    1    |
| 8  6  14  | 3   f124 7  |  5     9   g24   |
|-----------+-------------+------------------|
| 45 2  7   | 1    6   49 |  8     345 c3459 |
| 45 8  9   | 7    3   2  |  1     45   6    |
| 3  1  6   | 49   5   8  | b49    2    7    |
*--------------------------------------------*

9 r1c7 - 2 r1c7; *

9 r1c7 - r9c7 = (9-5) r7c9 = (5-2) r3c9 = r3c5 - r6c5 = r6c9 - r4c7 *= (2-6) r2c7 = (6-9) r1c7; => - 9 r1c7; stte

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Re: November 18, 2017

Postby SteveG48 » Sat Nov 18, 2017 12:54 am

Code: Select all
 *-----------------------------------------------------------*
 | 16    34    25    | 248   7     35    | 469-2  18    2349  |
 | 16    7     25    | 248   9     35    | 46-2  18    234   |
 | 9     34    8     | 6    b24    1     | 7     345  a2345  |
 *-------------------+-------------------+-------------------|
 | 7     5     134   | 249  c124  c49    |f234   6     8     |
 | 2     9     34    | 5     8     6     |f34    7     1     |
 | 8     6     14    | 3    c124   7     | 5     9     4-2   |
 *-------------------+-------------------+-------------------|
 | 45    2     7     | 1     6    d49    | 8     345   3459  |
 | 45    8     9     | 7     3     2     | 1     45    6     |
 | 3     1     6     |e49    5     8     |f49    2     7     |
 *-----------------------------------------------------------*


2r3c9 = r3c5 - (2=149)b5p238 - 9r7c6 = r9c4 - (9=234)r459c7 => -2 r6c9,r12c7 ; stte
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Re: November 18, 2017

Postby Marty R. » Sat Nov 18, 2017 1:12 am

Code: Select all
+-----------+------------+---------------+
| 16 34 25  | 248 7   35 | 2469 18  2349 |
| 16 7  25  | 248 9   35 | 246  18  234  |
| 9  34 8   | 6   24  1  | 7    345 2345 |
+-----------+------------+---------------+
| 7  5  134 | 249 124 49 | 234  6   8    |
| 2  9  34  | 5   8   6  | 34   7   1    |
| 8  6  14  | 3   124 7  | 5    9   24   |
+-----------+------------+---------------+
| 45 2  7   | 1   6   49 | 8    345 3459 |
| 45 8  9   | 7   3   2  | 1    45  6    |
| 3  1  6   | 49  5   8  | 49   2   7    |
+-----------+------------+---------------+

Play this puzzle online at the Daily Sudoku site

DP (25-35-23)r12c369
9r1c9=4r12c9-(4=2)r6c9-(2=349)r459c7=> -9r1c7
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Re: November 18, 2017

Postby SteveG48 » Sat Nov 18, 2017 1:24 am

Marty, that is a thing of beauty!
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Re: November 18, 2017

Postby pjb » Sat Nov 18, 2017 2:26 am

Code: Select all
 16      34      25     | 28-4   7      35     | 2469   18     2349   
 16      7       25     | 28-4   9      35     | 246    18     234   
 9       34      8      | 6     f24     1      | 7      345    2345   
------------------------+----------------------+---------------------
 7       5       134    | 249    124    49     |c234    6      8     
 2       9       34     | 5      8      6      |c34     7      1     
 8       6       14     | 3     e124    7      | 5      9     d24     
------------------------+----------------------+---------------------
 45      2       7      | 1      6      49     | 8      345    3459   
 45      8       9      | 7      3      2      | 1      45     6     
 3       1       6      |a49     5      8      |b49     2      7     

(4=9)r9c4 - (9=4)r9c7 - r45c7 = (4-2)r6c9 = r6c5 - (2=4)r3c5 => -4 r12c4; stte
shorter: (4=9)r9c4* - (9=4)r9c7 - (4=2)r45c7 - (2=4)r4c4* => -4 r12c4; stte
or
(4=5)r8c8 - r3c8 = (5-2)r3c9 = r3c5 - r6c5 = r6c9 - (2=4)r45c7 => -4 r9c7; stte

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Re: November 18, 2017

Postby eleven » Sat Nov 18, 2017 9:30 am

Same:
pjb wrote:shorter: (4=9)r9c4* - (9=4)r9c7 - (4=2)r45c7 - (2=4)r4c4* => -4 r12c4; stte

(4=9)r9c4-(9=2)r459c6-(2=4)r49c4 => -4r12c4, stte
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Re: November 18, 2017

Postby Cenoman » Sat Nov 18, 2017 2:38 pm

Code: Select all
 +------------------+-------------------+----------------------+
 |  16   34   25    |  248   7     35   |  2469   18    2349   |
 |  16   7    25    |  248   9     35   |  246    18    234    |
 |  9    34   8     |  6     24    1    |  7      345   2345   |
 +------------------+-------------------+----------------------+
 |  7    5   b134*  |eh49-2 e124   49   |af234*   6     8      |
 |  2    9    34*   |  5     8     6    | f34*    7     1      |
 |  8    6   c14    |  3    d124   7    |  5      9     24     |
 +------------------+-------------------+----------------------+
 |  45   2    7     |  1     6     49   |  8      345   3459   |
 |  45   8    9     |  7     3     2    |  1      45    6      |
 |  3    1    6     | g49    5     8    | f49     2     7      |
 +------------------+-------------------+----------------------+

UR(34)r45c37 using internals
(2)r4c7==(1)r4c3 - r6c3 = (1-2)r6c5 = r4c45 - (2=9)r459c7 - r9c4 = (9)r4c4 => -2 r4c4; lclste

And now a question to DP experts:
Why the pattern (134)r456c3, r46c5, r45c7 is not a deadly pattern ?
According to the definition here, the first two requirements are met:
- 3 solutions
- unchanged footprint
I am stuck with the 3rd requirement "no (cell,value) pairs in common"
pairs in common between what ? I can't catch the meaning of this incomplete assertion. Please help !

In addition, in the referenced document, it is asserted that no 7 cells-DP exists, while in this other document (here) discussing also deadly patterns, a 7-cells example similar to the above is displayed. I am lost...

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Re: November 18, 2017

Postby Marty R. » Sat Nov 18, 2017 7:43 pm

And now a question to DP experts:
Why the pattern (134)r456c3, r46c5, r45c7 is not a deadly pattern ?


Let me make it perfectly clear that I am not an expert on DPs or anything else.
Does the interchangeability shown in the grids mean that it IS a DP?

Code: Select all

 

| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
| . . 3 | . 1 . | 4 . . |
| . . 4 | . . . | 3 . . |
| . . 1 | . 4 . | . . . |
+-------+-------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+




Code: Select all
+-------+-------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
| . . 1 | . 4 . | 3 . . |
| . . 3 | . . . | 4 . . |
| . . 4 | . 1 . | . . . |
+-------+-------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+

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Re: November 18, 2017

Postby eleven » Sat Nov 18, 2017 7:45 pm

The pattern is deadly.
Code: Select all
. . 134 |  . 14 . | . 34 .
. .  34 |  .  . . | . 34 .
. .  14 |  . 14 . | . .  .

It is a combination of 2 unique rectangles. To avoid the 14 UR, the 3 digit cell must be 3, to avoid the 34 UR it must be 1 - but it can't be both.

Have a look at Myth's thread Forming MUGs from BUG-Lite composites from 2006. It also shows, that it is often tricky to show, that a pattern is deadly - or not.
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Re: November 18, 2017

Postby Cenoman » Sat Nov 18, 2017 9:12 pm

eleven wrote:The pattern is deadly.

Thank you eleven, for the confirmation, the rationale and the link. I have to read this asap !!!

The reason of my question was to validate the following very simple solution:
Code: Select all
 +------------------+-------------------+----------------------+
 |  16   34   25    | d248   7     35   |  2469   18    2349   |
 |  16   7    25    | d248   9     35   |  246    18    234    |
 |  9    34   8     |  6     4-2   1    |  7      345   2345   |
 +------------------+-------------------+----------------------+
 |  7    5    134*  | c249  a124*  49   | b234*   6     8      |
 |  2    9    34*   |  5     8     6    |  34*    7     1      |
 |  8    6    14*   |  3    a124*  7    |  5      9     24     |
 +------------------+-------------------+----------------------+
 |  45   2    7     |  1     6     49   |  8      345   3459   |
 |  45   8    9     |  7     3     2    |  1      45    6      |
 |  3    1    6     |  49    5     8    |  49     2     7      |
 +------------------+-------------------+----------------------+

DP(134)r456c3, r46c5, r45c7 using internals:
(2)r46c5==(2)r4c7 - r4c4 = (2)r12c4 => -2 r3c5; stte

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Re: November 18, 2017

Postby eleven » Sat Nov 18, 2017 9:40 pm

The puzzle is full of DP's. Here is another one.
Code: Select all
+-------------------+-------------------+--------------------+
|#16    34    25    |#28+4  7     35    |#26+49 #18    2349  |
|#16    7     25    |#28+4  9     35    |#26+4  #18    234   |
| 9     34    8     | 6     24    1     | 7      345   2345  |
+-------------------+-------------------+--------------------+
| 7     5     134   | 249   124   49    |c2*34   6     8     |
| 2     9     34    | 5     8     6     |c34     7     1     |
| 8     6     14    | 3     124   7     | 5      9    d4-2   |
+-------------------+-------------------+--------------------+
| 45    2     7     | 1     6     49    | 8      345   3459  |
| 45    8     9     | 7     3     2     | 1      45    6     |
| 3     1     6     |a49    5     8     |b49     2     7     |
+-------------------+-------------------+--------------------+

DP 1268 in r12c1478: 4r12c4=2r4c7
2r4c7=DP=4r12c4-r9c4=r9c7-r45c7=r6c9 => -2r6c9, stte
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