The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |...|...|.18|
 |...|1.8|75.|
 |5..|.7.|4..|
 |---+---+---|
 |1..|..6|..3|
 |..6|2.3|1..|
 |3..|7..|..4|
 |---+---+---|
 |..3|.1.|..6|
 |.52|8.4|...|
 |81.|...|...|
 *-----------*


Play/Print this puzzle online

[Leren]

Code: Select all

*--------------------------------------------*
| 279 36 79  | 459  249  259  | 36   1    8  |
| 249 36 49  | 1   a36   8    | 7    5    29 |
| 5   8  1   |b36   7    29   | 4   c36   29 |
|------------+----------------+--------------|
| 1   7  58  | 49   489  6    | 259  29   3  |
| 49  49 6   | 2    5    3    | 1    8    7  |
| 3   2  58  | 7    8-9  1    | 569 d69   4  |
|------------+----------------+--------------|
| 479 49 3   | 59   1    2579 | 8    249  6  |
| 6   5  2   | 8   a39   4    | 39   7    1  |
| 8   1  479 | 36   2369 279  | 239  2349 5  |
*--------------------------------------------*

(9=6) r28c5 - r3c4 = r3c8 - (6=9) r6c8 => - 9 r6c5; stte

Leren

[Wecoc]

Nice one, lots of naked pairs and naked triples.
Many possible X-Wings too, but a lot aren't really used:
X-Wing (3) in r3c4-r3c8-r9c4-r9c8
X-Wing (5) in r4c3-r4c7-r6c3-r6c7
X-Wing (4) in r1c4-r1c5-r4c4-r4c5
X-Wing (5) in r1c4-r1c6-r7c4-r7c6
X-Wing (8) in r4c3-r4c5-r6c3-r6c5

Coloring this one could be quite interesting.

[SteveG48]

Code: Select all

 *-----------------------------------------------------------*
 | 279   36    79    | 459   249   259   | 36    1     8     |
 | 249   36    49    | 1    b36    8     | 7     5     29    |
 | 5     8     1     |c36    7     29    | 4    d36    29    |
 *-------------------+-------------------+-------------------|
 | 1     7     8-5   | 49    489   6     | 259   29    3     |
 | 49    49    6     | 2     5     3     | 1     8     7     |
 | 3     2   ae58    | 7   ae89    1     | 69-5 e69    4     |
 *-------------------+-------------------+-------------------|
 | 479   49    3     | 59    1     2579  | 8     249   6     |
 | 6     5     2     | 8    b39    4     | 39    7     1     |
 | 8     1     479   | 36    2369  279   | 239   2349  5     |
 *-----------------------------------------------------------*


(5=89)r6c35 - (9=36)r28c5 - 6r3c4 = r3c8 - (6=589)r6c358 => -5 r4c3,r6c7 ; stte

[Cenoman]

Code: Select all

 +-------------------+----------------------+---------------------+
 |  279   36   79    |  459   249    259    |  36     1      8    |
 |  249   36   49    |  1    e36     8      |  7      5      29   |
 |  5     8    1     | d36    7      29     |  4     c36     29   |
 +-------------------+----------------------+---------------------+
 |  1     7    58*   | a49#   489*   6      |  259*  b29#    3    |
 |  49    49   6     |  2     5      3      |  1      8      7    |
 |  3     2    58*   |  7     8-9*   1      |  569* ca69#    4    |
 +-------------------+----------------------+---------------------+
 |  479   49   3     |  59    1      2579   |  8      249    6    |
 |  6     5    2     |  8    f39     4      |  39     7      1    |
 |  8     1    479   |  36    2369   279    |  239    2349   5    |
 +-------------------+----------------------+---------------------+

DP(589)r46c357 using externals:
(9)r4c4|r6c8 == (9)r4c8 - (96=3)r36c8 - r3c4 = r2c5 - (3=9)r8c5 => -9 r6c5; ste

Edit: replaced chain.

[Ngisa]

Code: Select all

+---------------------+-------------------------+---------------------+
|f279      36     79  | 459     e249      d259  | 36      1        8  |
|g249      36    h49  | 1        36        8    | 7       5        29 |
| 5        8      1   | 369      7        d29   | 4       2369     29 |
+---------------------+-------------------------+---------------------+
| 1        7      58  | 49       489       6    | 259   ka29       3  |
| 49       49     6   | 2        5         3    | 1       8        7  |
| 3        2      58  | 7        89        1    | 569     6-9      4  |
+---------------------+-------------------------+---------------------+
|j479     j49     3   | 59       1        c2579 | 8     kb249      6  |
| 6        5      2   | 8        39        4    | 39      7        1  |
| 8        1     i479 | 36       2369      279  | 239     2349     5  |
+---------------------+-------------------------+---------------------+


(9=2)r4c8 - r7c8 = r7c6 - r13c6 = r1c5 - r1c1 = (2-4)r2c1 = r2c3 - r9c3 = r7c12 - (4=2|9)r47c8 => - 9r6c8; stte

Clement

[SpAce]

Code: Select all

.-----------------.---------------------.-------------------.
| d279   36   79  | c49+5  c49+2  259   | 36      1      8  |
| e249   36  e49  |  1      36    8     | 7       5      29 |
|  5     8    1   |  36     7     29    | 4       36     29 |
:-----------------+---------------------+-------------------:
|  1     7    58  |  49+    49+8   6    | 259   ag2(9)   3  |
|  49    49   6   |  2      5      3    | 1       8      7  |
|  3     2    58  |  7     A8(#9)  1    | 569     6-9    4  |
:-----------------+---------------------+-------------------:
|  479  b49   3   | b59     1      2579 | 8    abg24(9)  6  |
|  6     5    2   |  8      39     4    | 39      7      1  |
|  8     1   f479 |  36     2369   279  | 239    g2349   5  |
'-----------------'---------------------'-------------------'


UR(49)r14c45 using mixed +internals/#external

(9)r6c5 == [(92)r47c8 = (495)r7c824 - (5==2)r1c45 - r1c1 = (24)r2c13 - r9c3 = (429)r974c8] => -9 r6c8; stte

Added. A bit simpler:

Code: Select all

.----------------.------------------.-------------------.
| 279  36    79  | 459   249   259  |  c36     1     8  |
| 249  36    49  | 1     36    8    |   7      5     29 |
| 5    8     1   | 36    7     29   |   4      36    29 |
:----------------+------------------+-------------------:
| 1    7     58  | 49    489   6    |   259    29    3  |
| 49   49    6   | 2     5     3    |   1      8     7  |
| 3    2   a(5)8 | 7    a89    1    | c(6)9-5  69    4  |
:----------------+------------------+-------------------:
| 479  49    3   | 59    1     2579 |   8      249   6  |
| 6    5     2   | 8    b39    4    |  c39     7     1  |
| 8    1     479 | 36    2369  279  |   239    2349  5  |
'----------------'------------------'-------------------'

AHS-H3-Wing:

(5=89)r6c35 - r8c5 = (936)r816c7 => -5 r6c7; stte

[SpAce]

(9=2)r4c8 - r7c8 = r7c6 - r13c6 = r1c5 - r1c1 = (2-4)r2c1 = r2c3 - r9c3 = r7c12 - (4=2|9)r47c8 => - 9r6c8; stte

Hi Clement. Your last node should be (4=29)r47c8 (i.e. 2 AND 9). With the '|' it means 2 OR 9, which doesn't guarantee that 9 is there (which we need for the elimination).

[Ngisa]

(9=2)r4c8 - r7c8 = r7c6 - r13c6 = r1c5 - r1c1 = (2-4)r2c1 = r2c3 - r9c3 = r7c12 - (4=2|9)r47c8 => - 9r6c8; stte

Hi Clement. Your last node should be (4=29)r47c8 (i.e. 2 AND 9). With the '|' it means 2 OR 9, which doesn't guarantee that 9 is there (which we need for the elimination).

What is important is that, we remain with 29 in r4c8 and r7c8 which guarantees the elimination of 9 in in r6c8. eliminating 4 in r7c8 leaves a pair 29 in r4c8 and r7c8 as the chain shows, how can 9 still be r6c8 as you want us to believe? I will avoid using that symbol as much as possible. Some say it means candidates not in the same cell. It confuses me. We should stick to the meaning which was given earlier by Hodoku (an un ordered group in a box).

[SpAce]

(9=2)r4c8 - r7c8 = r7c6 - r13c6 = r1c5 - r1c1 = (2-4)r2c1 = r2c3 - r9c3 = r7c12 - (4=2|9)r47c8 => - 9r6c8; stte

Hi Clement. Your last node should be (4=29)r47c8 (i.e. 2 AND 9). With the '|' it means 2 OR 9, which doesn't guarantee that 9 is there (which we need for the elimination).

What is important is that, we remain with 29 in r4c8 and r7c8 which guarantees the elimination of 9 in in r6c8. eliminating 4 in r7c8 leaves a pair 29 in r4c8 and r7c8 as the chain shows,

Isn't that exactly what I said? (29) means a pair of (2 AND 9) and that's what you need there (like you said yourself) because it guarantees that 9 is in one or the other cell (giving you the elimination). However, you wrote (2|9) which doesn't work because it only guarantees that either 2 OR 9 is in those cells, not necessarily both of them -- which doesn't guarantee that 9 is there at all (even though the chain itself does). Can't you see the difference? It's a correct chain that way too, but it just doesn't prove the elimination because of the unnecessary OR in the last node. It must be AND for it to work. What part of that don't you understand?

how can 9 still be r6c8 as you want us to believe?

Because your end node doesn't guarantee that 9 is in r47c8. I'm sure everyone else believes it without me saying it. It's just you who don't see it.

I will avoid using that symbol as much as possible.

Well, you certainly avoid the '|' when it's actually needed, and I wouldn't even bother mentioning that again, but this case was different: you used it when it shouldn't have been there. Why? If you use a symbol, it should mean something. What did you mean by it here? It doesn't even match the obsolete "unordered group in a box" definition you've used before.

Some say it means candidates not in the same cell.

Who says? What does that even mean? Why don't you finally believe that on this forum '|' means OR and nothing else?

It confuses me.

That much is clear. Unfortunately I don't think there's anything I can say that would clarify the matter, because I (among others) have tried my best to explain it before. Like I've also said before, I can easily understand your chains even if they're written a bit weirdly, and there's nothing wrong with their intended logic (which is what really matters), so it's no big deal if you prefer to stick to your way. You should, however, accept the fact that they're often not correctly written according to the forum standards. It's fine by me if you don't care about that, but arguing about it is useless. It's a fact.

(Btw, I do realize that the same fact is true about some of my own stylistic choices, which some have also complained about, but at least I admit it. Another difference is that I can write perfectly standard chains if I choose to.)

We should stick to the meaning which was given earlier by Hodoku (an un ordered group in a box).

I don't think Hodoku has any opinion on the matter. It doesn't use Eureka. What you're probably referring to, once again, is this obsolete Sudopedia article. While most of it is still valid, this part is not -- at least not on this forum. Again, it's a fact whether you believe it or not. I've said it before but probably won't say again, because it's obviously a waste of time. You're free to believe what you want and use whatever notation you want. You just can't expect the rest of us to consider it correct.