The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |..6|9.8|2..|
 |...|.6.|...|
 |18.|.2.|.46|
 |---+---+---|
 |2.8|.7.|6.4|
 |7.1|...|3.5|
 |4.3|.8.|7.1|
 |---+---+---|
 |81.|.5.|.73|
 |...|.3.|...|
 |..5|7.4|8..|
 *-----------*


Play/Print this puzzle online

[Leren]

w-wing (29) => r8c1 <> 9; stte

Leren

[eleven]

Same, or

Code: Select all

+-------------------+-------------------+-------------------+
|#35   *34    6     | 9     14    8     | 2    #135   7     |
|#359  *2347  2479  | 145   6     157   |*159  #135   8     |
| 1     8     79    | 35    2     357   |*59    4     6     |
+-------------------+-------------------+-------------------+
| 2     5     8     | 13    7     13    | 6     9     4     |
| 7     69    1     | 246   49    269   | 3     8     5     |
| 4     69    3     | 56    8     569   | 7     2     1     |
+-------------------+-------------------+-------------------+
| 8     1     29    | 26    5     269   | 4     7     3     |
| 69    47    47    | 8     3    -129   |a15    156   29    |
| 369  b23    5     | 7    d19    4     | 8    -16   c29    |
+-------------------+-------------------+-------------------+

DP 35 in r12c18: either r23c7=5 or r12c2=3
r23c7=5 -> r8c7=1
r12c2=3 -> r9c2=2 -> r9c9=9 -> r9c5=1
=> r8c6, r9c8<>1

(1=5)r8c7-5r23c7=(DP35r12c18)3r12c2-(3=2)r9c2-(2=9)r9c9-(9=1)r9c5; r8c6,r9c8<>1

[tlanglet]

I also found the AUR(35) but used the internal SIS.

AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1

I altered my notation of ALSs per the comments posted by DonM in yesterdays puzzle. Hopefully he will see this notation and comment.

[ArkieTech]

AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1

Here is another style:

(1r12c8=9r2c1)dp:35r12c18-(9=63)r89c1-(3=291)r9c295 => -1r9c8

[Marty R.]

w-wing (29) => r8c1 <> 9; stte

I saw it as an M-Wing before I noticed that it worked as a W as well with the same eliminations.

[DonM]

I also found the AUR(35) but used the internal SIS.

AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1

I altered my notation of ALSs per the comments posted by DonM in yesterdays puzzle. Hopefully he will see this notation and comment.

Excellent! It shows the actual logic flow of the ALS. Incidentally, deadly patterns are an example of where it is particularly difficult to standardize notation, but fwiw, I prefer your presentation/use of the AUR above- it labels the AUR, shows where it is and then shows the relevant SIS in square brackets. It is extremely easy to follow.

[daj95376]

I'm still having fun with notation.

Code: Select all

 after basics
 +--------------------------------------------------------------+
 | b35    34    6     |  9     14    8     |  2    a135   7     |
 | b359   2347  2479  |  145   6     157   |  159  a135   8     |
 |  1     8     79    |  35    2     357   |  59    4     6     |
 |--------------------+--------------------+--------------------|
 |  2     5     8     |  13    7     13    |  6     9     4     |
 |  7     69    1     |  246   49    269   |  3     8     5     |
 |  4     69    3     |  56    8     569   |  7     2     1     |
 |--------------------+--------------------+--------------------|
 |  8     1     29    |  26    5     269   |  4     7     3     |
 | c69    47    47    |  8     3     129   | d15   d156   29    |
 |  369   23    5     |  7     19    4     |  8     6-1   29    |
 +--------------------------------------------------------------+
 # 57 eliminations remain

 (1=35)r12c8 -UR- (35=9)r12c1 - (9=6)r8c1 - (6=15)r8c78  =>  r9c8<>1


[tlanglet]

I also found the AUR(35) but used the internal SIS.

AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1

I altered my notation of ALSs per the comments posted by DonM in yesterdays puzzle. Hopefully he will see this notation and comment.

Excellent! It shows the actual logic flow of the ALS. Incidentally, deadly patterns are an example of where it is particularly difficult to standardize notation, but fwiw, I prefer your presentation/use of the AUR above- it labels the AUR, shows where it is and then shows the relevant SIS in square brackets. It is extremely easy to follow.

Don, thanks for your feedback. I agree that your notation better reflects the logic flow entering an ALS, but I find it lacking on the logic flow exiting the ALS. Here are some examples which I hope do a better job of expressing my views rather than poor verbiage.

1) AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1
This is the notation I posted for this puzzle. I clearly states that the logic flow is to delete the 9 from the ALS, but does not explicitly state the resulting digit of interest provided by the ALS; is it a 3 or a 6. In my post, I ordered the ALS location information to implicitly indicate the resulting ALS digit of interest last but that would not be obvious to someone learning about ALSs and notations.

2) AUR(35)r12c18[1r12c8=9r2c1]-(69=3)r89c1-(329=1)r9c295 => r9c8<>1
This is the format I used previously, which is simply the reverse of the above example. It messes up the logic entering into the ALS and also relies on implicit location info to indicate the resulting ALS digit of interest, but it does explicitly identify the resulting ALS digit of interest.

Why not notate this in the fashion used for AURs?
3) AUR(35)r12c18[1r12c8=9r2c1]-ALS(369)r89c1[9r89c1=3r9c1]-ALS(1239)r9c259[3r9c2=1r9c5] => r9c8<>1
It is noticeable longer but also has the advantage of telling the learning community that they are dealing with an ALS.

Ted

Cocktails anyone?????

[RW]

After the first singles:

Code: Select all

 *--------------------------------------------------------------------*
 | 35     34     6      | 9      14     8      | 2      135    7      |
 | 359    23479  2479   | 1345   6      1357   | 159    135    8      |
 | 1      8      79     | 35     2      357    | 59     4      6      |
 |----------------------+----------------------+----------------------|
 | 2      5      8      | 13     7      13     | 6      9      4      |
 | 7     *69     1      |#246    49    *269    | 3      8      5      |
 | 4     *69     3      |#56     8     *569    | 7      2      1      |
 |----------------------+----------------------+----------------------|
 | 8      1      249    | 2-6    5      269    | 49     7      3      |
 | 69     24679  2479   | 8      3      1269   | 1459   156    29     |
 | 369    2369   5      | 7      19     4      | 8      16     29     |
 *--------------------------------------------------------------------*

UR in r56c26 suggests r7c4<>6. I'll let you guys figure out the notation..

[Marty R.]

After the first singles:

Code: Select all

 *--------------------------------------------------------------------*
 | 35     34     6      | 9      14     8      | 2      135    7      |
 | 359    23479  2479   | 1345   6      1357   | 159    135    8      |
 | 1      8      79     | 35     2      357    | 59     4      6      |
 |----------------------+----------------------+----------------------|
 | 2      5      8      | 13     7      13     | 6      9      4      |
 | 7     *69     1      |#246    49    *269    | 3      8      5      |
 | 4     *69     3      |#56     8     *569    | 7      2      1      |
 |----------------------+----------------------+----------------------|
 | 8      1      249    | 2-6    5      269    | 49     7      3      |
 | 69     24679  2479   | 8      3      1269   | 1459   156    29     |
 | 369    2369   5      | 7      19     4      | 8      16     29     |
 *--------------------------------------------------------------------*

UR in r56c26 suggests r7c4<>6. I'll let you guys figure out the notation..

2r5c6-r78c6=2r7c4
5r6c6-(5=6)r6c4-(6=2)r7c4=>r7c4=2

Or do it with pincers:

(2r5c6=5r6c6)-(5=6)r6c4-(6=2)r7c4=>r78c6<>2

[DonM]

I also found the AUR(35) but used the internal SIS.

AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1

I altered my notation of ALSs per the comments posted by DonM in yesterdays puzzle. Hopefully he will see this notation and comment.

Excellent! It shows the actual logic flow of the ALS. Incidentally, deadly patterns are an example of where it is particularly difficult to standardize notation, but fwiw, I prefer your presentation/use of the AUR above- it labels the AUR, shows where it is and then shows the relevant SIS in square brackets. It is extremely easy to follow.

Don, thanks for your feedback. I agree that your notation better reflects the logic flow entering an ALS, but I find it lacking on the logic flow exiting the ALS. Here are some examples which I hope do a better job of expressing my views rather than poor verbiage.

1) AUR(35)r12c18[1r12c8=9r2c1]-(9=63)r89c1-(3=291)r9c295 => r9c8<>1
This is the notation I posted for this puzzle. I clearly states that the logic flow is to delete the 9 from the ALS, but does not explicitly state the resulting digit of interest provided by the ALS; is it a 3 or a 6. In my post, I ordered the ALS location information to implicitly indicate the resulting ALS digit of interest last but that would not be obvious to someone learning about ALSs and notations.

2) AUR(35)r12c18[1r12c8=9r2c1]-(69=3)r89c1-(329=1)r9c295 => r9c8<>1
This is the format I used previously, which is simply the reverse of the above example. It messes up the logic entering into the ALS and also relies on implicit location info to indicate the resulting ALS digit of interest, but it does explicitly identify the resulting ALS digit of interest.

Why not notate this in the fashion used for AURs?
3) AUR(35)r12c18[1r12c8=9r2c1]-ALS(369)r89c1[9r89c1=3r9c1]-ALS(1239)r9c259[3r9c2=1r9c5] => r9c8<>1
It is noticeable longer but also has the advantage of telling the learning community that they are dealing with an ALS.

Ted

Ted, your post above reminds me of the type of discussion that occurred when the Eureka notation was being formulated (for lack of a better word) in 2006-2007, a discussion sadly lost with the rest of the Eureka forum.

Of your 3 notation variations, (IMO) only the first shows clearly what is going on with the ALSs. Restating my original point in a slightly different way: in the fragment from #1 notation example above showing the 2 ALSs: (9=63)r89c1-(3=291)r9c295 , right away one can see both the ALS and the LS in brackets: (9=63) if not 9 then 63, (3=291) if not 3 then 291. To my mind that is an exact representation of what is going. It doesn't matter whether the 'resulting ALS digit of interest' isn't isolated since what immediately follows the ALS notation makes that 'digit of interest' very clear.

I do like the use of ALS label in the 3rd example and always use it in my notation.

You might be interested in the following link if you're not already familiar with it. It is Myth Jellies' thread that probably introduced more people to AICs than any other and helped start a solving trend that replaced Nice Loop notation with AIC notation. It's interesting that with this thread Myth introduced his own AIC notation, but a little over a year later replaced his notation with Eureka notation. IMO, this link could be added to examples of a standard for ALS notation from 'the early days'.

alternating-inference-chains-t3865.html

If you cycle down to the end of his first post (dated Apr 15, 2006) you'll notice the following which shows his Eureka notation for an ALS. (Myth liked to place an AND between the digits of the locked set, but few others included that.)

Code: Select all

 ALS example
 *-----------*
 |.6.|5..|.1.|
 |...|3..|..4|
 |..8|.9.|2..|
 |---+---+---|
 |4.7|2..|...|
 |.5.|.7.|.8.|
 |...|..9|1.7|
 |---+---+---|
 |..3|.4.|6..|
 |1..|..7|...|
 |.8.|..5|.2.|
 *-----------*
 *--------------------------------------------------------------------*
 | 2379   6      49     | 5      28     48     | 3789   1      389    |
 | 259    179    159    | 3      1268   168    | 589    79     4      |
 | 35     14     8      | 7      9      14     | 2      356    356    |
 |----------------------+----------------------+----------------------|
 | 4     A139    7      |-2     -1568  -1368   | 359    3569   3569   |
 |A69    -5     A169    | 146    7     B36     | 349    8      2      |
 | 8      23     26     | 46     56     9      | 1      3456   7      |
 |----------------------+----------------------+----------------------|
 | 59     79     3      | 18     4      2      | 6      579    18     |
 | 1      249    24569  | 689    36     7      | 34589  3459   3589   |
 | 679    8      469    | 169    136    5      | 3479   2      139    |
 *--------------------------------------------------------------------*
 A3=A(1&6&9)-B6=B3

Eureka notation
(3=1&6&9)r4c2,r5c13 - (6=3)r5c6


Edit:
This topic inspired me to go through my many manilla envelopes of printed matter from the early Players and Eureka forums in search of the first thread(s) that gave birth to the Eureka notation and some of the (possible) standards developed. I had trouble finding the main one because it turned out it was named 'Bivalue-Bilocation Chain Documentation' from the Eureka forum July 25, 2006. It essentially is the thread that gave birth to Eureka notation. In the discussion, Myth Jellies figures strongly in the discussion along with Ruud (author of Sudocue and Moderator of the original Eureka forum).

Some interesting quotes from that 2006 thread:
Ruud: 'One last point. The use of the ALS in the chain notation needs to be reviewed. I cannot get the hang of it and I do not consider myself an average player. Let's work on that part.'

John MacLeod: 'We all have our own preferences for notation, but there is something to be said for using an accepted standard.

In that thread, Myth Jellies proposes the following for an ALS: ALS(1=387)r8c789 (though he then goes on to modifiy it by dropping the ALS and adding ampersands between the digits 387).

But here is one of the most interesting bits of info in this thread regarding the source of the name: Eureka notation and when it was first used, something that I was not aware of or if I was I had totally forgotten it:

On Aug 2, 2006 Ruud: Following a suggestion by David P Bird, I will call this the 'Eureka' notation. It is a good scientific practice to name discoveries after the place they were found. It also reflects the team effort that has gone into it.

A round of applause for David Bird!

[tlanglet]

Don, thanks for all the interesting and useful info. Sadly, I had not previously seen some/most of the info posted in the 2006 era. In fact, I was not even aware of Sudoku at that time.

Ted