The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |.21|4..|.5.|
 |..6|..5|..1|
 |8..|.2.|...|
 |---+---+---|
 |1.7|5..|.42|
 |...|.3.|...|
 |23.|..7|9.5|
 |---+---+---|
 |...|.6.|..3|
 |5..|9..|6..|
 |.6.|..3|19.|
 *-----------*


Play/Print this puzzle online

[SteveG48]

Code: Select all

 *-----------------------------------------------------------*
 | 3     2     1     | 4     789   89    | 78    5     6     |
 | 49    49    6     | 3     78    5     | 2     78    1     |
 | 8     7     5     | 6     2     1     | 4     3     9     |
 *-------------------+-------------------+-------------------|
 | 1     89    7     | 5     89    6     | 3     4     2     |
 | 6     5    b49    | 2     3     9-4   | 78    1     78    |
 | 2     3     48    | 18    14    7     | 9     6     5     |
 *-------------------+-------------------+-------------------|
 | 479   1489 a89    | 178   6    a248   | 5    a28    3     |
 | 5     148   3     | 9     14    248   | 6     278   478   |
 | 47    6     2     | 78    5     3     | 1     9     48    |
 *-----------------------------------------------------------*


(4=289)r7c368 - (9=4)r5c3 => -4 r5c6 ; stte

[JC Van Hay]

Code: Select all

+-----------------+-------------------+---------------+
| 3    2     1    | 4      789   89   | 78  5     6   |
| 49   49    6    | 3      7(8)  5    | 2   7(8)  1   |
| 8    7     5    | 6      2     1    | 4   3     9   |
+-----------------+-------------------+---------------+
| 1    9(8)  7    | 5      9(8)  6    | 3   4     2   |
| 6    5     49   | 2      3     49   | 78  1     78  |
| 2    3     4(8) | 1(8)   14    7    | 9   6     5   |
+-----------------+-------------------+---------------+
| 479  1489  9(8) | 17(8)  6     24-8 | 5   2-8   3   |
| 5    148   3    | 9      14    248  | 6   278   478 |
| 47   6     2    | 7(8)   5     3    | 1   9     48  |
+-----------------+-------------------+---------------+


Jellyfish{8R24C34} -> -{8r7c68}; stte

[Sudtyro2]

Code: Select all

 *------------------------------------------------------------*
 | 3     2     1     | 4    *78+9  89    |*78    5      6     |
 | 49    49    6     | 3    *78    5     | 2    *78     1     |
 | 8     7     5     | 6     2     1     | 4     3      9     |
 |-------------------+-------------------+--------------------|
 | 1     89    7     | 5     89    6     | 3     4      2     |
 | 6     5     49    | 2     3     49    |*78    1     *78    |
 | 2     3     48    | 1-8D  14C   7     | 9     6      5     |
 |-------------------+-------------------+--------------------|
 | 479   1489  89    | 178   6     248   | 5     28b    3     |
 | 5     148   3     | 9     14B   248   | 6    *78+2a *78+4A |
 | 47    6     2     | 78d   5     3     | 1     9      48c   |
 *------------------------------------------------------------*

Valid pattern? An 8-cell(*) ADP(78), using internals:

Code: Select all

2r8c8 - (2=8)r7c8 - 8r9c9 = 8r9c4 - 8r6c4;
4r8c9 - 4r8c5 = (4-1)r6c5 = 1r6c4 - 8r6c4;
9r1c5 - (9=8)r4c5                 - 8r6c4; stte

SteveC

[Sudtyro2]

Code: Select all

+-----------------+-------------------+---------------+
| 3    2     1    | 4      789   89   | 78  5     6   |
| 49   49    6    | 3      7(8)  5    | 2   7(8)  1   |
| 8    7     5    | 6      2     1    | 4   3     9   |
+-----------------+-------------------+---------------+
| 1    9(8)  7    | 5      9(8)  6    | 3   4     2   |
| 6    5     49   | 2      3     49   | 78  1     78  |
| 2    3     4(8) | 1(8)   14    7    | 9   6     5   |
+-----------------+-------------------+---------------+
| 479  1489  9(8) | 17(8)  6     24-8 | 5   2-8   3   |
| 5    148   3    | 9      14    248  | 6   278   478 |
| 47   6     2    | 7(8)   5     3    | 1   9     48  |
+-----------------+-------------------+---------------+


Jellyfish{8R24C34} -> -{8r7c68}; stte

Hi JC,

Code: Select all

       b    b
 .  .  . |  .  8  8 |  8  .  .
 .  .  . |  .  8  . |  .  8  .
 .  .  . |  .  .  . |  .  .  .
---------+----------+---------
 .  8  . |  .  8  . |  .  .  .
 .  .  . |  .  .  . |  8  .  8
 .  .  8 |  8  .  . |  .  .  . c
---------+----------+---------
 .  8  8 |  8  . -8 |  . -8  . c
 .  8  . |  .  .  8 |  .  8  8
 .  .  . | #8  .  . |  .  .  8

Sorry to be both slow and rusty on real Fish...
Could you supply the full UFG-style rcb\rcb notation for your Jellyfish?
Best I could do for the same eliminations was:
Finned X-Wing c34\r67 + rfr9c4 => -8r7c68

Code: Select all

Fin:        r9c4                              => -8r7c6
Remote fin: r9c4 - r78c6 = r1c6 - r1c7 = r2c8 => -8r7c8

SteveC

[SteveG48]

Valid pattern?

Yup. Looked at that one but didn't make it work. Well done.

Couldn't figure out JC's fish either, but I rarely catch a fish. Gun man myself.

[Cenoman]

Code: Select all

 +--------------------+--------------------+-------------------+
 |  3     2      1    |  4     789   89    |  78   5     6     |
 |  49    49     6    |  3     78    5     |  2    78    1     |
 |  8     7      5    |  6     2     1     |  4    3     9     |
 +--------------------+--------------------+-------------------+
 |  1     89     7    |  5     89    6     |  3    4     2     |
 |  6     5      49   |  2     3     49    |  78   1     78    |
 |  2     3      48   |  18    14    7     |  9    6     5     |
 +--------------------+--------------------+-------------------+
 | d479   1489   89   | e178   6     248   |  5    28    3     |
 |  5     148    3    |  9    f1-4   248   |  6    278  a478   |
 | c47    6      2    |  78    5     3     |  1    9    b48    |
 +--------------------+--------------------+-------------------+

(4)r8c9 = r9c9 - (4=7)r9c1 - r7c1 = (7-1)r7c4 = (1)r8c5 => -4 r8c5; stte

Cenoman

[Cenoman]

@SteveG and SteveC

My understanding of JC's jellyfish:
(8)r7c3=r6c3 - r6c4=r79c4 => -8 r7c6 (XW using strong links in C3 and C4)
(8)r2c8=r2c5 - r4c5=r4c2 - r6c3=r7c3 => -8 r7c8 (SF using strong links in R2, R4 and C3)
Set of strong links used C3, C4, R2, R4, i.e. 4 strong links between 8's consistant with JC's diagram, hence the qualification of jellyfish.

I don't know wether this is in accordance with tarek's "Ultimate fish guide", but I assume it is...

Cenoman.

[SteveG48]

@SteveG and SteveC

My understanding of JC's jellyfish:
(8)r7c3=r6c3 - r6c4=r79c4 => -8 r7c6 (XW using strong links in C3 and C4)
(8)r2c8=r2c5 - r4c5=r4c2 - r6c3=r7c3 => -8 r7c8 (SF using strong links in R2, R4 and C3)
Set of strong links used C3, C4, R2, R4, i.e. 4 strong links between 8's consistant with JC's diagram, hence the qualification of jellyfish.

I don't know wether this is in accordance with tarek's "Ultimate fish guide", but I assume it is...

Cenoman.

Thanks, Big C. I know that I'm a lousy angler, but I thought that I could at least recognize a fish when I saw one. To me, you have a fish if you can list base sets and cover sets and fins. If the definition now extends to sets of strong links, I'm lost. The solution is simple enough when expressed as two chains, but when I try to handle it as a jellyfish, I get stung.

[JC Van Hay]

Could you supply the full UFG-style rcb\rcb notation for your Jellyfish?

SteveC,

I only have one method to solve a puzzle whatever its level of difficulty or its number of solutions :
"The solutions of a set P={C1, ..., CN} of N constraints exclude a set X of candidates".

Here, the 3 solutions of the 8 exclude a set X={8r1c7, 8r2c5, 8r5c9, 8r7c68, 8r8c8} of 6 candidates for the digit 8.
Just have a look at the following too obvious analysis of the 8s from the Y-cluster aA, pivot r6c3.

Code: Select all

 .  .  . |  .  8A 8a| -8  .  .
 .  .  . |  . -8  . |  .  8aA.
 .  .  . |  .  .  . |  .  .  .
---------+----------+---------
 .  8A . |  .  8a . |  .  .  .
 .  .  . |  .  .  . |  8aA. -8
 .  .  8a|  8A .  . |  .  .  .
---------+----------+---------
 .  8  8A|  8  . -8 |  . -8  .
 .  8  . |  .  .  8A|  . -8  8
 .  .  . |  8  .  . |  .  .  8A

The puzzle than solves with singles.
However, after inspection, the only needed exclusions to solve the puzzle with singles are 8r7c68.
The smallest set of constraints proving these exclusions is 4 : the solutions of P={8R24C34} exclude X={8r7c68}.

Now, in view of this, why should I make any reference to cover sets despite the fact that I called Jellyfish this set P ?
To justify the exclusions in another way ?
But then, how to justify the way the fish is found ?

JC

[Sudtyro2]

... why should I make any reference to cover sets despite the fact that I called Jellyfish this set P?

To my knowledge, the "Jellyfish" term is specially reserved under UFG guidelines as a particular Fish "species" that normally also includes specific reference to its number and identification of base\cover sectors as well as to any "fin" designations. This would not seem to relate in an obvious way to your "... one method to solve a puzzle whatever its level of difficulty or its number of solutions."

Admittedly, for your one advanced solution method, I'm pretty much under water, as they say. And even my own UFG-based X-Wing solution posted earlier was derived not from any special Fish code or strong-weak-link observational technique, but rather from a simple list procedure introduced by arcilla and discussed here.

In the 8s grid, arcilla's row-per-column list, (3)(478)(67)(679)(124)(178)(15)(278)(589), has two bolded entries that form an obvious pseudo-ALS indicating that cover rows 6 and 7 plus base columns 3 and 4 form a 2x2 (X-Wing) Fish with a fin at r9c4. That fin leads easily to the two desired eliminations.

SteveC

[JasonLion]

JC Van Hay,

An interesting technique, kind of a human accessible variant/simplification of templating.

I agree with Sudtyro2, nothing to do with Jellyfish, or any other kind of fish for that matter.