Looking for a rule: finned x wing

Advanced methods and approaches for solving Sudoku puzzles

Postby ronk » Tue Oct 24, 2006 12:32 pm

tarek wrote:So it is....... I was caged in this "No boxes in the base sectors".....I'm free now........
Lots of laughs! You're much easier to convince than Mike.

tarek wrote:So in a sense... this is a finless franken Jellyfish....According to what we are trying to do here:?::!:

So now we have.......

Finless franken fish: N SECTORS * N SECTORS (No extras"Fins")
Finned franken fish: N SECTORS * N SECTORS (with extras "Fins")
Agreed. I've even caught some "finned franken swordfish" with one row, one column and one box in both the base and cover sets. Grouped colored was easier though IIRC (if I recall correctly). If anyone is interested, I'll try to catch another.

tarek wrote:6. Kraken (later?)
Postponed forever maybe. I think fish, even with the inclusion of mixed sector types, should be limited to those which have potential exclusions with either no fin ... or one fin. Any "fish on life support" should be "almost fish" IMO.

tarek wrote:The sashimi term probably is redundant ..... I'm insisting on it because if we refer to everything as finned, it may confuse junior fishermen & I'm sure that sashimi will then come back with a vengance
Agree here too.
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Postby Havard » Tue Oct 24, 2006 1:29 pm

I am quite liking where this is going!:)

Slightly redefining "Franken" to mean "a fish that has one or more covering sectors that are a box", is fine with me. The original Frankenfish had at least TWO boxes used for covering, but if it is a strong will of the community to make the Frankenfish even more common among the sealife, I am quite happy with that.:)

Adding "finless" and "finned" should also keep it from getting mixed up with the previous definition.

I never have and never will use the "sashimi" term, but if it can do any good not confusing young fishermen, I agree it should be kept.

And finally, for laughs, find the smaller fish::)

Code: Select all
Canniballistic Finned-FrankenLeviathan.
 14   2      3     |  7     5    9    |  148    148     6     
 8    7     *14    |  2     6   *134  |  5      9      #134   
 9    56     56    | *138  *138 *1348 |  7      2      #134   
-------------------+------------------+-----------------------
 26  *156   *12568 | *1358  4   *138  |  9      7      *158   
 3   *145    7     | *158   9    6    | *148   *1458    2     
#14  *1459  *14589 | *158   2    7    |  36     36    -*1458 
-------------------+------------------+-----------------------
 5   *1369  *1269  |  4     7   *138  | *12368 *1368   *189   
 67  *13469 *1469  |  69   *138  2    | *13468 *134568 *15789
 267  8     *12469 |  69   *13   5    | *12346 *1346   *1479 
Basis-Sectors: (8) Row 2, Row 3, Row 4, Row 5, Row 6, Row 7, Row 8, and Row 9
Cover-Sectors: (7) Column 2, Column 3, Column 4, Column 5, Column 6, Box 6, and Box 9
Fins: (3) r23c9 r6c1
Elimination: r6c9<>1


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Postby tarek » Tue Oct 24, 2006 2:21 pm

Havard wrote:And finally, for laughs, find the smaller fish::)
Code: Select all
*--------------------------------------------------------------------------*
|*14      2       3      | 7       5       9      |*148    *148     6      |
| 8       7       14     | 2       6       134    | 5       9      #134    |
| 9       56      56     | 138     138     1348   | 7       2      #134    |
|------------------------+------------------------+------------------------|
| 26      156     12568  | 1358    4       138    | 9       7       158    |
| 3       145     7      | 158     9       6      | 148     1458    2      |
|*14      1459    14589  | 158     2       7      | 36      36     -1458   |
|------------------------+------------------------+------------------------|
| 5       1369    1269   | 4       7       138    | 12368   1368    189    |
| 67      13469   1469   | 69      138     2      | 13468   134568  15789  |
| 267     8       12469  | 69      13      5      | 12346   1346    1479   |
*--------------------------------------------------------------------------*
Eliminating 1 From r6c9 (Finned Franken XWing in c1b3 & r1r6  with fin in r2c9,r3c9)


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Postby ronk » Tue Oct 24, 2006 2:25 pm

Havard wrote:Basis-Sectors: (8) Row 2, Row 3, Row 4, Row 5, Row 6, Row 7, Row 8, and Row 9
Cover-Sectors: (7) Column 2, Column 3, Column 4, Column 5, Column 6, Box 6, and Box 9

When the number of base sectors does not equal the number of cover sectors, I'm suspicious of the conclusion. Besides, all one needs is the strong links in box 3 and col 1.

But I'll try to find a smaller fish later.
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Postby Havard » Tue Oct 24, 2006 2:27 pm

ronk wrote:When the number of base sectors does not equal the number of cover sectors, ...

in this case being one smaller, you can eliminate all candidates that all of your "extras" or fins can see.

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Postby ronk » Tue Oct 24, 2006 3:02 pm

Havard wrote:in this case being one smaller, you can eliminate all candidates that all of your "extras" or fins can see.

In this case those extras are part of the strong links in column 1 and box 3 that make the fish irrelevant anyway. Have you got a better example?

And with a smaller fish, the actual algegra of a rigorous proof (or disproof) would be reasonable.
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Postby RW » Tue Oct 24, 2006 3:48 pm

tarek wrote:The sashimi term probably is redundant ..... I'm insisting on it because if we refer to everything as finned, it may confuse junior fishermen & I'm sure that sashimi will then come back with a vengance


I was once a young fisherman. Then I stumbled upon this forum and was confronted with lots of weird fishes in several variations. To me it was mostly confusing at it appeared like there's lots of names for the same pattern. I thought a finned fish is very simple, and of course there might be missing candidates, an ordinary swordfish doesn't need all corners in place either. So why do people keep using different names for it all the time? Not until I read this thread did I learn the difference between a sashimi fish and ordinary finned fish, and I've managed quite well to capture lots of fish without this knowledge also. You don't need the 'sashimi' for finless fishes with missing candidates, so why is it relevant for the finned versions?

What I'm trying to say is that too much terminology is not helpful for any beginner. It's hard enough to learn the basic terms X-wing, swordfish and Jellyfish in one reading, adding multiple variations makes it really confusing. AFAIK none of us here is a professional author of educational material, so the definitions threads have a tendency to be confusing anyway. Also, these fishes often apply to situations that could be considered other non-fish patterns as well, which makes the whole area of nishio based contradictions even a bit more confusing. I can imagine the newbie who right now is scratching his head, trying to find out the difference between an Empty Rectangle and a Finned Franken Swordfish...

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Postby tarek » Tue Oct 24, 2006 4:15 pm

RW wrote:You don't need the 'sashimi' for finless fishes with missing candidates, so why is it relevant for the finned versions?

This is debatable RW, & I think that that the 2 comparisons are not actually equal. The smallest Jellyfish has a 2*2*2*2 pattern which you trace using cells that contain the candidate in question.....(I've never heard someone saying a Jellyfish missing 8 cells)

It is therefore easier IMO in the finned jellyfish to do the same for a beginner "if these extra cells were not here we would have had a 2*2*2*2 Jellyfish"....... & is much much easier to explain, because you comapare it to a known pattern

In a sashimi you can't do that, you have to imagine a virtual fish to make the statement above (sometimes u don't even have the 2*2*2*2 pattern) (the easiest example is the sashimi x-wing vs the finned x-wing)....... In the equivalent Turbot we used to say "an X-wing with a skewed point" in the Sashimi, you can't do that because that skewed point is now the "fin".

I myself haven't used the term sashimi at all in the past, but I noticed how it was used to cause confusion. I think that the confusion after removing it would be greater. we can use sashimi as a step higher from the easier finned fish.

This is my personal opinion & as nohing has been finalised, is still open for debate.

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Postby RW » Tue Oct 24, 2006 5:13 pm

tarek wrote:It is therefore easier IMO in the finned jellyfish to do the same for a beginner "if these extra cells were not here we would have had a 2*2*2*2 Jellyfish"....... & is much much easier to explain, because you comapare it to a known pattern

In a sashimi you can't do that, you have to imagine a virtual fish to make the statement above (sometimes u don't even have the 2*2*2*2 pattern) (the easiest example is the sashimi x-wing vs the finned x-wing).......

Code: Select all
 . | . | | . . | . | .
 . X . | X . . | . X .
 . | . | | . . | . | .
-------+-------+-------
 . | . | # . . | . | .
 . X . |(.)* * | . X .
 . | . | # . . | . | .
-------+-------+-------
 . | . | | . . | . | .
 . | . | | . . | . | .
 . X . | X . . | . X .

This example posted by ronk does not seem like a very imaginary virtual fish to me without the #-cells. I understand that you are refering to a fish with only one fish candidate in one of the units, and yes, I think it should be mentioned in a 'fishing for dummies' thread, but I don't think it's necessary to define it as an own species. But this is just my opinion, I usually try to generalize things to as universal patterns as possible. Actually when I solve puzzles, I never spot fishes, I usually first see the nishio contradiction and then I might ask myself wether it is a fish or not.

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Postby daj95376 » Tue Oct 24, 2006 5:52 pm

Thanks everyone for the in-depth analysis and naming/re-naming lesson. I promise never again to reference any fish more complicated than a Jellyfish!
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Postby tarek » Tue Oct 24, 2006 6:33 pm

RW wrote:I understand that you are refering to a fish with only one fish candidate in one of the units, and yes, I think it should be mentioned in a 'fishing for dummies' thread, but I don't think it's necessary to define it as an own species

As I said RW, what you say has some merit. again, I don't like even the word "Sashimi"........

If you want to generalise, then we could simply put 1 rule which is the N sector* N sector....everything should fall under it...... you don't need to tell an advanced player the name of the pattern .... This is aimed towards the general public ...junior & advanced ....Most of them have already fixed ideas of what fish are.

it is easier for people to build up on what they know: basic ---> Finned -----> Sashimi -----> Whatever transition is what I would use.... The only way to insure that, is by putting it in a category of its own.

if you use basic -----> Finned (including Sashimi) -----> Whatever....

Then you would end up with several differant opinions/ways on how to explain what a finned fish is & I'm sure that the word "variation" would be used often & the it is "The return of Sashimi".

but if you use the Sashimi as a category of its own you could always refer in your explanation to the much easier finned pattern to explain it.

The evidence is easy..... I & several other players do not use the word sashimi....... yet the word keeps coming back again & again & again.... it seems that it is there to stay.... The word "finned" managed to dominate the term "filet-O-fish" but couldn't dominate the word sashimi:(

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Postby Mike Barker » Tue Oct 24, 2006 6:58 pm

Here's another 2c worth. I have nothing against using boxes in the basis set if one is talking about constraint subsets. I'm looking forward to finding new eliminations with this approach. My objection is calling these fish. The problem is that suddenly a Franken fish may look nothing like what someone would expect. Consider Ocean's fish - weird. Also the term becomes much more general - it would be like calling an XYZ-wing an ALS (I've had that discussion before too). You can do it, but it conveys less information. So if I had my druthers, I'd leave Frankenfish as n rows or columns and give a new name to combined row/column/box basis sets. How about a "Box Fish" and a "finned Box fish" or for the unimaginative a "constraint subset" and "almost constraint subset" or for the more imaginative _________________ (fill in the blank)?
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Postby ronk » Tue Oct 24, 2006 7:51 pm

Mike Barker wrote:How about [ed: ...] "constraint subset" and "almost constraint subset" or [ed: ...]?

The "sub" doesn't convey any useful info AFAIK, so those could just as well be "constraint set" and "almost constraint set". But, other than that, that's actually a pretty good idea.

We could define NxN constraint sets that subsume the x-wing, swordfish, jellyfish and squirmbag patterns ... including the unfinned, finned and sashimi ... and the franken versions of them too ... and then add the myriad of other possibilities in a 9x9 sudoku.

A simple equivalence table of names could ease the transition from fishies to constraint sets ... for those who wish to actually make the transition.
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Postby Havard » Tue Oct 24, 2006 8:39 pm

I would have to agree with Mike on this one, using more than just columns or rows as basis-sectors should have some other name to indicate just that. It is a bit of a stretch for me to call one box and one column/row for an x-wing. But I guess this will become more and more complex with a possible combination of all three sectors both in basis and cover, hence demanding a new terminology. I still think that spelling out the basis and covers will provide more relevant and better information than any name will be able to.:)

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Postby Ruud » Tue Oct 24, 2006 9:18 pm

In Sudoku variations, there are alternative patterns for finned Fish.

Here is a finned Sudoku-X-Wing:

Code: Select all
 . . . | . . . | . . .
 . . . | . . . | . * .
 . . * | . . . | . . .
-------+-------+-------
 . . . | . . . | . . .
 - - X | - # - | - X -
 . . . | . . . | . . .
-------+-------+-------
 . . * | . . . | . . .
 . . . | . . . | . * .
 - - X | - - - | - X -


This example uses both diagonals, but a single diagonal can also be used.

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