The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |...|..9|..8|
 |.6.|...|.1.|
 |..7|52.|...|
 |---+---+---|
 |..2|..6|7..|
 |..5|.1.|...|
 |4..|3..|...|
 |---+---+---|
 |...|7..|2..|
 |.3.|...|.8.|
 |1..|...|..6|
 *-----------*


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[Leren]

Code: Select all

*--------------------------------------------------------------------------------*
|c25     c1245   c134      | 16      3467    9        |c345    c27      8        |
| 2589    6       3489     | 48      3478    3478     | 3459    1       27       |
| 89      489-1   7        | 5       2       1348     | 3469    3469    349      |
|--------------------------+--------------------------+--------------------------|
| 389    a189     2        | 489     4589    6        | 7       3459    13459    |
| 36789  a789     5        | 2489    1       2478     | 34689   23469   2349     |
| 4      a1789    1689     | 3       5789    2578     | 1689    2569    1259     |
|--------------------------+--------------------------+--------------------------|
| 5689    4589    4689     | 7       34689   1348     | 2       349     1349     |
| 27      3       469      | 16      4569    1245     | 149     8       57       |
| 1      a27     b489      |b2489   b34589  b23458    |b349    b57      6        |
*--------------------------------------------------------------------------------*

ALS XY Wing: (1=2) r4569c2 - (2=7) r9c345678 - (7=1) r1c12378 => - 1 r3c2; stte

Leren

[pjb]

Code: Select all

 25      1245   a134    |i6-4   h3467   9      | 345   g27     8     
 2589    6       3489   | 48     3478   3478   | 3459   1      27     
 89      1489    7      | 5      2      1348   | 3469   3469   349   
------------------------+----------------------+---------------------
 389     189     2      | 489    4589   6      | 7      3459   13459 
c36789   789     5      | 2489   1      2478   | 34689  23469  2349   
 4       1789   b1689   | 3      5789   2578   | 1689   2569   1259   
------------------------+----------------------+---------------------
 5689    4589    4689   | 7      34689  1348   | 2      349    1349   
d27      3       469    |j16     4569   1245   | 149    8     e57     
 1       27      489    | 2489   34589  23458  | 349   f57     6     


(1)r1c3 = (1-6)r6c3 = (6-7)r5c1 = r8c1 - (7=5)r8c9 - (5=7)r9c8 - r1c8 = (7-6)r1c5 = r1c4 - (6=1)r8c4 => -1 r1c4; stte

Phil

[SpAce]

Code: Select all

.-------------------.-------------------------.---------------------.
| 25     1245 g134  |b16     a3(6)-47  9      | 345    27     8     |
| 2589   6    g3489 |g(48)   g3(478)  g3(478) | 3459   1      27    |
| 89     1489  7    | 5       2        1348   | 3469   3469   349   |
:-------------------+-------------------------+---------------------:
| 389    189   2    | 489     4589     6      | 7      3459   13459 |
| 36789  789   5    | 2489    1        2478   | 34689  23469  2349  |
| 4      1789 f1689 | 3       5789     2578   |e1689   2569   1259  |
:-------------------+-------------------------+---------------------:
| 5689   4589  4689 | 7       34689    1348   | 2      349    1349  |
| 27     3     469  |c16      4569     1245   |d149    8      57    |
| 1      27    489  | 2489    34589    23458  | 349    57     6     |
'-------------------'-------------------------'---------------------'

(6)r1c5 = (6-1)r1c4 = r8c4 - r8c7 = r6c7 - r6c3 = (13)r12c3 - (3=847)r2c456 => -47 r1c5; stte

[SteveG48]

Code: Select all

 *--------------------------------------------------------------------*
 | 25    a1245  a134    |h6-1   g3467   9      | 345   f27     8      |
 | 2589   6      3489   | 48     3478   3478   | 3459   1      27     |
 | 89    b1489   7      | 5      2      1348   | 3469   3469   349    |
 *----------------------+----------------------+----------------------|
 | 389   b189    2      | 489    4589   6      | 7      3459   13459  |
 | 36789 b789    5      | 2489   1      2478   | 34689  23469  2349   |
 | 4     b1789   1689   | 3      5789   2578   | 1689   2569   1259   |
 *----------------------+----------------------+----------------------|
 | 5689   4589   4689   | 7      34689  1348   | 2      349    1349   |
 |c27     3      469    | 16     4569   1245   | 149    8     d57     |
 | 1     b27     489    | 2489   34589  23458  | 349   e57     6      |
 *--------------------------------------------------------------------*


1r1c23 = (12789)r34569 - (2=7)r8c1 - r8c9 = r9c8 - r1c8 = (7-6)r1c5 = 6r1c4 => -1 r1c4 ; stte

[Cenoman]

Code: Select all

 +------------------------+-------------------------+--------------------------+
 |  25      1245  b134    | g16    g3467    9       |  345    g27      8       |
 | a589-2   6     b3489   |  48     3478    3478    | a3459    1      h27      |
 |  89      1489   7      |  5      2       1348    |  3469    3469    349     |
 +------------------------+-------------------------+--------------------------+
 |  389     189    2      |  489    4589    6       |  7       3459    13459   |
 |  36789   789    5      |  2489   1       2478    |  34689   23469   2349    |
 |  4       1789  c1689   |  3      5789    2578    | d1689    2569    1259    |
 +------------------------+-------------------------+--------------------------+
 |  5689    4589   4689   |  7      34689   1348    |  2       349     1349    |
 |  27      3      469    | f16     4569    1245    | e149     8       57      |
 |  1       27     489    |  2489   34589   23458   |  349     57      6       |
 +------------------------+-------------------------+--------------------------+

HP(59)r2c17 = (93-1)r12c3 = r6c3 - r6c7 = r8c7 - r8c4 = (167-2)r1c458 = (2)r2c9 => -2 r2c1; ste

[SpAce]

(6)r1c5 = (61)r18c4 - (1)r8c7 = r6c7 - r6c3 = (13)r12c3 - (3=847)r2c456 => -47 r1c5; stte

Hmm. The second node makes no sense to me, because the (61) pair is not caused or broken by either link around it -- only the order of those digits within the pair is determined. Looks like I tried too hard to compact the chain. I think it should be expanded:

(6)r1c5 = (6-1)r1c4 = r8c4 - r8c7 ...

Or would a comma (in this case depicting the order) be enough to make it work logically:

(6)r1c5 = (6,1)r18c4 - (1)r8c7 ...

What do you think?

[SteveG48]

(6)r1c5 = (61)r18c4 - (1)r8c7 = r6c7 - r6c3 = (13)r12c3 - (3=847)r2c456 => -47 r1c5; stte

Hmm. The second node makes no sense to me, because the (61) pair is not caused or broken by either link around it -- only the order of those digits within the pair is determined. Looks like I tried too hard to compact the chain. I think it should be expanded:

(6)r1c5 = (6-1)r1c4 = r8c4 - r8c7 ...

Or would a comma (in this case depicting the order) be enough to make it work logically:

(6)r1c5 = (6,1)r18c4 - (1)r8c7 ...

What do you think?

I like your first fix better. Even if the use of the comma does what you want (beats me), many people are not going to understand it. Like you, I strive to make my chains as short as possible, but clarity trumps brevity.

[SpAce]

(6)r1c5 = (6-1)r1c4 = r8c4 - r8c7 ...

Or would a comma (in this case depicting the order) be enough to make it work logically:

(6)r1c5 = (6,1)r18c4 - (1)r8c7 ...

I like your first fix better. Even if the use of the comma does what you want (beats me), many people are not going to understand it. Like you, I strive to make my chains as short as possible, but clarity trumps brevity.

Thanks for the feedback, Steve! I took your advice and used the first fix.

I still think the second one could work too if there were a generally accepted standard for specifying the digit order. In that case the first strong link would mean that either (r1c5=6 OR (r1c4=6 and r8c4=1)), i.e. the digit order (6,1) and the cell order (r18c4) must match. The other direction is not as intuitive, but I think it would work too if read as: if r8c7=1 then NOT (r8c4=1 AND r1c4=6) -- which leaves the opposite order (r8c4=6 AND r1c4=1) as the only possibility justifying the following strong link (though not as explicitly as saying (1-6)r1c4). Does that make any sense?

Nevertheless, I won't push that notation if it causes confusion. Apparently there isn't such a standard, and I still can't find the document which originally gave me the idea that there was (and that commas were used for that purpose). I don't think it would be a bad idea to have such a standard, though, because it might clarify certain situations where the exact digit distribution in ALS nodes matters. Here it's easy to circumvent by splitting the node (more readable anyway) but it might not always be as simple.

[SteveG48]

I still think the second one could work too if there were a generally accepted standard for specifying the digit order. In that case the first strong link would mean that either (r1c5=6 OR (r1c4=6 and r8c4=1)), i.e. the digit order (6,1) and the cell order (r18c4) must match. The other direction is not as intuitive, but I think it would work too if read as: if r8c7=1 then NOT (r8c4=1 AND r1c4=6) -- which leaves the opposite order (r8c4=6 AND r1c4=1) as the only possibility justifying the following strong link (though not as explicitly as saying (1-6)r1c4). Does that make any sense?

It makes perfect sense. The issue, of course, it is the generally accepted standard.

I think David Bird has alternate ways of writing things like this, but I'm not well versed in them, and I don't know whether they are well accepted among more advanced players.