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[ArkieTech]

Code: Select all

 *-----------*
 |...|.2.|...|
 |.5.|...|.9.|
 |..7|3.8|6..|
 |---+---+---|
 |76.|8.2|.49|
 |.34|.1.|86.|
 |...|...|...|
 |---+---+---|
 |1..|...|..5|
 |.7.|...|.8.|
 |98.|5.4|.31|
 *-----------*
 

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[pjb]

Code: Select all

 3468  b149    1389   | 14679  2      15679  | 1357   157    3478   
 23468  5      1238   | 1467   467    167    | 1237   9      23478 
a24     19     7      | 3      59     8      | 6      15     24     
 ---------------------+----------------------+---------------------
 7      6      15     | 8      35     2      | 135    4      9     
 5-2    3      4      | 79     1      579    | 8      6      27     
 58-2  d129    12589  | 467    467    3567   | 12357  1257   237   
 ---------------------+----------------------+---------------------
 1     c24     236    | 2679   8      3679   | 49     27     5     
 2345   7      235    | 129    39     139    | 49     8      6     
 9      8      26     | 5      67     4      | 27     3      1     


(2=4) r3c1 - r1c2 = (4-2) r7c2 = r6c2, => r56c1 <> 2; stte

Phil

[Leren]

Code: Select all

*--------------------------------------------------------------*
| 3468 a149   1389   | 14679 2     15679  | 1357  157   378-4  |
| 23468 5     1238   | 1467  467   167    | 1237  9     23478  |
| 2-4  a19    7      | 3     59    8      | 6     15   c24     |
|--------------------+--------------------+--------------------|
| 7     6     15     | 8     35    2      | 135   4     9      |
|b25    3     4      |b79    1    b579    | 8     6    c27     |
| 258  a129   12589  | 467   467   3567   | 12357 1257  237    |
|--------------------+--------------------+--------------------|
| 1     24    236    | 2679  8     3679   | 49    27    5      |
| 2345  7     235    | 129   39    139    | 49    8     6      |
| 9     8     26     | 5     67    4      | 27    3     1      |
*--------------------------------------------------------------*

Just because it produces different eliminations...
als-xy-wing: (4=2) r136c2 - (2=7) r5c146 - (7=4) r35c9 => -4 r1c9, r3c1; stte

Leren

[eleven]

Code: Select all

 +-------+-------+-------+
 | . . . | . 2 . | . . . |
 | . 5 . | . . . | . 9 . |
 | # . 7 | 3 . 8 | 6 . # |
 +-------+-------+-------+
 | 7 6 . | 8 . 2 | . 4 9 |
 | b 3 4 | . 1 . | 8 6 . |
 | . . . | . . . | . a . |
 +-------+-------+-------+
 | 1 # . | . 8 . | . . 5 |
 | . 7 . | . . . | . 8 6 |
 | 9 8 @ | 5 . 4 | @ 3 1 |
 +-------+-------+-------+

r7c2 and (triple 159 in r3) r3c1 only can be 24.
Strong link for 2 in r9, r9c3=2->r7c2=4.
r9c7=2->(c8)r6c8=2->r5c1=2->r3c1=4
=> r1c2<>4,r7c2=4

[Marty R.]

Same M-Wing as Phil.

[Leren]

The m-wing works 2 ways

(2=4) r3c1 - r1c2 = (4-2) r7c2 = r6c2, => r56c1 <> 2 or
(2=4) r3c1 - r8c1 = (4-2) r7c2 = r6c2, => r56c1 <> 2

Another 1 stepper is produced by an h2-wing with a bi-value extension cell:

Code: Select all

(5=2) r5c1 - r6c2 = (2-4) r7c2 = r8c1;           => -5 r8c1;
                                   ||
                                    - (4=2) r3c1 => -2 r5c1;  stte

Leren

[Marty R.]

The m-wing works 2 ways

(2=4) r3c1 - r1c2 = (4-2) r7c2 = r6c2, => r56c1 <> 2 or
(2=4) r3c1 - r8c1 = (4-2) r7c2 = r6c2, => r56c1 <> 2

I actually fibbed a little. Phil used #1 and I used #2.

[7b53]

Code: Select all

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

r7c2 and (triple 159 in r3) r3c1 only can be 24.
Strong link for 2 in r9, r9c3=2->r7c2=4.
r9c7=2->(c8)r6c8=2->r5c1=2->r3c1=4
=> r1c2<>4,r7c2=4

how many other ways we can look at this for (r1c2<>4, r7c2=4)

from r3c1{2,4}
if r3c1=4 then r7c2=4
if r3c1=2 then r5c9=2 -> r7c8=2 -> r7c2=4
---or---
actually looking at box 6, doesn't matter where digit 2 is at (r5c9, r6c789)
they will all force r7c2=4.

guess these are call some type of forcing chain perhaps.....