The New Sudoku Players' Forum

[ronk]

We need a way to condense "boring segments" without calling them ALS. However, I have no respect for bastardizing a reasonable solution so it can be called an "ALS XY-Wing".

What "rule" for the name "ALS XY-Wing" would you propose to prevent this?

BTW sorry to hear about your recent bout with food poisoning.

[daj95376]

We need a way to condense "boring segments" without calling them ALS. However, I have no respect for bastardizing a reasonable solution so it can be called an "ALS XY-Wing".

What "rule" for the name "ALS XY-Wing" would you propose to prevent this?

BTW sorry to hear about your recent bout with food poisoning.

Yes, a week of food poisoning dropped me 10 lbs. in the first five days. It was rough going!


DAJ Rule for ALS Anything: No ALS element can be composed of multiple bivalue cells.

This means that Leren wouldn't be able to use (5=6) r8c25 in an ALS XY-Wing for this puzzle.

However, he could use it in a standard chain as a condensed, 2-SI representation of (5=7)r8c2 - (7=6)r8c5.

[ronk]

DAJ Rule for ALS Anything: No ALS element can be composed of multiple bivalue cells.

I think that would need to be relaxed to:

At least one ALS element must be comprised of at least one cell with at least three candidates.

[SteveG48]

I'm missing something and not seeing how the last term is (7=6)r8c5. There's a 6 in r5c5 and a 7 in r8c2. Those would seem to trap r8c5, leaving it=1. Six is how r8c5 ends up, but I'm not seeing how the 1 got accounted for to allow the 7=6.

Perhaps it's an uppercase 'I'. Perhaps someone will expound on their personal preference not to use this letter.

Sorry, guys. I've been out of town with no access. It is, indeed, an upper case I that I intended to mark the closing point of the discontinuous chain starting at a. I've kind of worried over the confusion. If you use lower case I, then it might be mistaken for a 1 also, depending on another user's choice of font. If you skip I in annotating a chain, then the reader might be lost looking for it when trying to follow the chain. I thought upper case I would be the clearest, but apparently not.

[Marty R.]

Steve,

Now I see the capital "I" that I mistook for a 1.

May I make a suggestion? About a year or two ago (on another forum) there was a suggestion that was adopted by most of us that when showing letters or other symbols to show the path, that they be in their own column. I.e., the numbers stay aligned in their columns and the letters/symbols stick out in their own columns to the left of the numbers.

Thanks and sorry I didn't look a little more closely.

[daj95376]

_

Code: Select all

Steve
.----------------.-------------.---------------.
| 257   3    257 | 6    4   9  | 28    1   258 |
| 8     6    25  | 3    1   7  | 4     9   25  |
| 1     9    4   | 28   5   28 | 3     7   6   |
:----------------+-------------+---------------:
| f57   f578 3   | 4    9   e25| 268   26  1   |
| 4     2    1   | 78   b67 c68| 9     5   3   |
| 9     g58  6   | 25   3   1  | 7     4   28  |
:----------------+-------------+---------------:
| 3     4    259 | 159  8   d56| 1256  26  7   |
| 2567  h57   8  | 157 aI67 4  | 1256  3   9   |
| 567   1    579 | 579  2   3  | 56    8   4   |
'----------------'-------------'---------------'

(6)r8c5 = r5c5 - r5c6 = (6-5)r7c6 = (5)r4c6 - r4c12 = r6c2 - (5=7)r8c2 - (7=6)r8c5 => r8c5 = 6 ; stte


When a cell is used twice, I add the second cell marker to the end of the candidates.

Code: Select all

 a..h,J   Note: cells "b" and "c" aren't necessary: (6)r8c5 = (6-5)r7c6
 +--------------------------------------------------------------+
 |  257   3     257   |  6     4     9     |  28    1     258   |
 |  8     6     25    |  3     1     7     |  4     9     25    |
 |  1     9     4     |  28    5     28    |  3     7     6     |
 |--------------------+--------------------+--------------------|
 | f57   f578   3     |  4     9    e25    |  268   26    1     |
 |  4     2     1     |  78   b67   c68    |  9     5     3     |
 |  9    g58    6     |  25    3     1     |  7     4     28    |
 |--------------------+--------------------+--------------------|
 |  3     4     259   |  159   8    d56    |  1256  26    7     |
 |  2567 h57    8     |  157  a67J   4     |  1256  3     9     |
 |  567   1     579   |  579   2     3     |  56    8     4     |
 +--------------------------------------------------------------+
 # 50 eliminations remain


Note: Since Steve's solution is a discontinuous loop, it's actually redundant to add r8c5=6.

Code: Select all

(6)r8c5 = (6-5)r7c6 = (5)r4c6 - r4c12 = r6c2 - (5=7)r8c2 - (7=6)r8c5   ; stte


However, he might have chosen to reduce it by one term and added a different conclusion.

Code: Select all

(6)r8c5 = (6-5)r7c6 = (5)r4c6 - r4c12 = r6c2 - (5=7)r8c2 => r8c5 <> 7 ; stte


[SteveG48]

Steve,

May I make a suggestion? About a year or two ago (on another forum) there was a suggestion that was adopted by most of us that when showing letters or other symbols to show the path, that they be in their own column.

Thanks, all. I'll see what I can do with this suggestion.