The New Sudoku Players' Forum

[ronk]

The fish name would then be:

Sashiminess + Finning + Shape + size
ex.
1. Sashimi Finned Mutant Jellyfish
2. non-sashimi unfinned basic swordfish

Regarding finning, fish have been said to be either 1) unfinned, 2) finned, or 3) sashimi.

I can't speak for others, but I'm reasonably sure I've only been using "non-sashimi" to mean a fish is either 1) or 2). But if that's a problem, I'd rather write "finned or unfinned fish" than add another adjective as you propose.

[hobiwan]

Since I came to this thread only recently and with very little knowledge about fish I can give you an outsider's view on the guide.

First and most important: The Guide is fantastic. IMHO (and not including variants, because I know nothing about that) there are two minor flaws: the definition of sashimi and cannibalism.

Base candidates:

for vanilla ....

Potential eliminations: cover sector candidates not part of any base sector + candidates at the intersection of cover sectors
Eventual eliminations: Potential eliminations that are seen by all Fin cells

For vanilla it could be something like that:

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*Potential elimination*: Either a candidate that occupies a cell within a "Cover sector" but not within a "Base sector" or a candidate that occupies a cell within a "Base sector" that lies within more than one "Cover sectors". In finned fish...

("that" possibly refers to "Base sector" now instead of "cell"; "which cell"?)

Sashimi:

My problem with the definition as it stands is, that due to the beautiful simplicity of your fish definition the following:

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 . . . | . / . | . / .
 * * * | * X * | * X *
 . . . | . / . | . / .
 ------+-------+------
 . . . | . / . | . / .
 . . . | . / . | . / .
 . . . | . / . | . / .
 ------+-------+------
 * * * | * / * | * X *
 . . . | . / . | . / .
 . . . | . / . | . / .

is a perfectly well formed basic x-wing (two base sectors, two cover sectors, all base candidates covered).

Unfortunatly that makes this:

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 . . . | . / . | . / .
 . . . | . X . | . X .
 . . . | . / . | . / .
 ------+-------+------
 . . . | . / . | . / .
 . . . | . / . | . / .
 . . . | . / . | . / .
 ------+-------+------
 . . . | * / * | . X .
 . . . | . X . | . / .
 . . . | . / . | . / .

a basic x-wing plus one uncovered base candidate, which is your definition of finned basic x-wing. With this, there is no more room for sashimi.

I realize, that the discovery of sashimi fish must have been really fascinating and that it was an important step towards more advanced fishing, and I am probably stepping out of line with this, but for practical application of fish in sudokus the term "sashimi" seems to add no necessary information and could therefore be dropped altogether.

If the term stays in the guide, I think it should get a general definition. In some other post (I don't remember which) it was put somewhat like that:

*Sashimi*: Any finned fish that degenerates in a series of basic moves or a fish of smaller size in absence of the fins.

[tarek]

hobiwan,
regarding Sashimi,
Sashimi simply means that without the fins, the fish degenerates into something SMALLER.
both your eaxamples are then considered sashimi.
your 1st is an unfinned sashimi basic x-wing (the X in column 5 is the last candidate left in the column)
the 2nd would lead to the same when you remove the fin r8c5.
your decision NOT to force the degenration in the 1st example, is a good example why the term sashimi can be applied even to unfinned fish

regarding Cannibalism,
the term I proposed is short (wording to be revised but essentially the number of words is around the same), if we start to use more "If ... then " statements, the simplicity would disappear.
however, if short means confusing & "what ifs" then bring on "if ... then statements"

I can't speak for others, but I'm reasonably sure I've only been using "non-sashimi" to mean a fish is either 1) or 2). But if that's a problem, I'd rather write "finned or unfinned fish" than add another adjective as you propose.

I hope that this addition of a new adjective would make things less confusing for some.

Fish name: adjective describing Finning status + adjective describing Sashimi status + adjective describing shape + size

examples: unfinned sashimi basic x-wing (hobiwan 1st example)
finned sashimi basic x-wing (hobiwan 2nd example)

I've also seen some examples where regular size terms (x-wing, swordfish, ....) have been replaced by (2-fish, 3-fish,.....).... to me that is fine & probably more universal. I don't think that they would replace them in common terminology though:(

tarek

[ronk]

Sashimi:

My problem with the definition as it stands is, that due to the beautiful simplicity of your fish definition the following:

Code: Select all

 . . . | . / . | . / .
 * * * | * X * | * X *
 . . . | . / . | . / .
 ------+-------+------
 . . . | . / . | . / .
 . . . | . / . | . / .
 . . . | . / . | . / .
 ------+-------+------
 * * * | * / * | * X *
 . . . | . / . | . / .
 . . . | . / . | . / .

is a perfectly well formed basic x-wing (two base sectors, two cover sectors, all base candidates covered).

No, that is a hidden single. For a single-digit constraint-set pattern to be an N-fish, i.e. a fish of size N, the pattern must not degenerate.

[tarek]

For a single-digit constraint-set pattern to be an N-fish, i.e. a fish of size N, the pattern must not degenerate.

Why ?....
essentially if degenration were not allowed to occur, then the eliminations are valid based on the x-wing.

why do u choose it to call it an x-wing when it actually degenrates into a cascade of singles is another issue.

that is the reason "Sashimi" can be used in these situations.

an unfinned sashimi N-fish remains a valid fish if you choose to avoid degenaration (the sashimi term in this instance is a giveaway that degeneration is the easier path)

tarek

[daj95376]

My latest viewpoint.

Code: Select all

Fin Cell: Any cell that's in more Base Sectors than Cover Sectors.


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Possible Elimination Cell: Any cell that's in more Cover Sectors than Base Sectors.


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Actual Elimination Cell: All possible elimination cells if no fin cells exist. Otherwise, all possible elimination cells that are a buddy to every fin cell. An exception to the buddy restriction exists for Kraken fish.


I have a table of 336 canonicalized hidden patterns for unfinned fish. Most of them degenerate through an initial Hidden Single, Locked Candidate (1), or Locked Candidate (2). A few others degenerate through an initial smaller fish. Degeneration is the dominant scenario for unfinned fish. Because of this, I think Sashimi should be dropped. If someone feels that non-degenerate fish need to be identified, then adding basic or non-Sashimi should be used. In addition, degeneration should be limited to a few techniques that are specifically identified.

With the above definition, endo/exo-fin cells are simply fin cells and do not need to be specifically identified. Only Kraken fish contain remote fin cells that must use a chain to perform the eliminations.

Any fish with non-remote fin cells should be identified as finned. This means that Kraken fish with only remote fin cells will not be identified as finned.

When a PM contains many fish patterns for multiple candidate values, it's a lot easier to order them for each candidate value if they're identified as N-Fish. It's also a nice format when comparing results if you aren't concerned about adjectives. I think N-Fish should be used under these conditions -- or if you're lazy like me.

[hobiwan]

No, that is a hidden single. For a single-digit constraint-set pattern to be an N-fish, i.e. a fish of size N, the pattern must not degenerate.

Not according to the definition in the mini-glossary ("degenerate" doesn't appear). I chose the examples deliberatly to show, why I couldn't (and still can't) see the difference between "2a. Finned" and "2b. Sashimi" according to the definitions in this guide.

regarding Cannibalism,
the term I proposed is short (wording to be revised but essentially the number of words is around the same), if we start to use more "If ... then " statements, the simplicity would disappear.
however, if short means confusing & "what ifs" then bring on "if ... then statements"

I see your point. When I first read your post I stumbled over the word "eventual", which sounds like the german word "eventuell", which means "possibly", so the whole thing didn't make much sense to me.

My latest viewpoint.

Code: Select all

Fin Cell: Any cell that's in more Base Sectors than Cover Sectors.

Code: Select all

Possible Elimination Cell: Any cell that's in more Cover Sectors than Base Sectors.

Code: Select all

Actual Elimination Cell: All possible elimination cells if no fin cells exist. Otherwise, all possible elimination cells that are a buddy to every fin cell. An exception to the buddy restriction exists for Kraken fish.

Sounds simple and complete and certainly fits anything I have seen so far.

Degeneration is the dominant scenario for unfinned fish. Because of this, I think Sashimi should be dropped.

I am with you on this, although I don't think it will get a majority. As a compromise "sashimi" could be made optional. That would mean to drop option 2b and add something like "Any fish that degrades into something smaller in absence of the fins may be called sashimi".

[daj95376]

hobiwan: Your first example does meet the definition of an X-Wing. However, since there isn't a fin cell, most solvers (like ronk) would use lesser techniques first because your pattern also degenerates. Therefore, from a practical point of view, your X-Wing pattern would never be encountered later when searching for fish patterns.

Fin cells prevent a fish pattern from degenerating. They have also become more complex since the early X-Wing variants. Therein lies the concern over degeneration and a search for more general definitions.

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 basic X-Wing            finned X-Wing           Sashimi X-Wing
                         fin cells [r89c5]       fin   cells [r89c5]
                                                 empty cell  [r7c5]

 . . . | . / . | . / .   . . . | . / . | . / .   . . . | . / . | . / .
 * * * | * X * | * X *   * * * | * X * | * X *   * * * | * X * | * X *
 . . . | . / . | . / .   . . . | . / . | . / .   . . . | . / . | . / .
 ------+-------+------   ------+-------+------   ------+-------+------
 . . . | . / . | . / .   . . . | . / . | . / .   . . . | . / . | . / .
 . . . | . / . | . / .   . . . | . / . | . / .   . . . | . / . | . / .
 . . . | . / . | . / .   . . . | . / . | . / .   . . . | . / . | . / .
 ------+-------+------   ------+-------+------   ------+-------+------
 * * * | * X * | * X *   * * * |** X **| * X *   * * * |** / **| * X *
 . . . | . / . | . / .   . . . | . X . | . / .   . . . | . X . | . / .
 . . . | . / . | . / .   . . . | . X . | . / .   . . . | . X . | . / .


I think the term Sashimi will always be attached to an X-Wing when appropriate. However, maybe it will only be used in limited cases for larger fish.

[hobiwan]

hobiwan: Your first example does meet the definition of an X-Wing. However, since there isn't a fin cell, most solvers (like ronk) would use lesser techniques first because your pattern also degenerates. Therefore, from a practical point of view, your X-Wing pattern would never be encountered later when searching for fish patterns.

I know that. I don't want to make a stand for fish that are really singles, I only wanted to point out that in my opinion the definition of sashimi is incomplete.

[tarek]

The idea is to get this "sashimi" out of my system once & for all - it has been bugging me for >2 years now ..........(I would love to change the term with degenerate vs stable or any other pair of antonyms)

use sashiminess as a seperate adjective then the current definition of sashimi holds & is complete. This means that hobiwan's 1st example is a unfinned sashimi x-wing. if you want it to degenerate or not it is left to you. It shouldn't be used an exemplar though.

If everybody insists on the sashimi term to remain overlapping the finned fish term then it is status quo again

anything that has un or non in the adjective can be dropped. the sashiminess adjective can be dropped too.

If you want to use the sashiminess adjective you have to couple it with the finning adjective.

so Finned sashimi <> sashimi (without extra info)
however Finned could be sashimi or non sashimi.

In simple terms
Parent: Finning adjective
Child: Sashiminess adjective

A child can't walk alone all by himself
A Parent can.

tarek

[ronk]

tarek, neither the "finned sashimi" nor the "unfinned sashimi" term appears in Myth Jellies' seminal thread on The Filet-O-Fish Rule. Therefore, IMO "finned sashimi" is redundant ... and "unfinned sashimi" is oxymoronic.

[tarek]

tarek, neither the "finned sashimi" nor the "unfinned sashimi" term appears in Myth Jellies' seminal thread on The Filet-O-Fish Rule.

I was hoping that we would move forward from that point. I can't see any contradiction between the proposal & what was in that thread.

IMO, the term sashimi is redundant. Its constant use has plagued fish. I'm not sure why I feel like this, but I'm thinking that others may feel the same .

Anyway, back to status quo.

tarek

[daj95376]

hobiwan: I'm sorry to have presented such a rudimentary explanation when I should have realized that you already have a strong grasp of Fish. I missed the subtlety of your query.

It took me awhile to realize what bothered me about your first example. Then I realized that it only has one candidate cell in c5. To the best of my knowledge, every Base/Cover Sector must have at least two candidate cells. I don't know if it's assumed or if it's been documented someplace. If it's documented, it's probably in a very old thread. Maybe even in the Programmers Forum.

Anyway, this explains why my examples don't include your first example. It also means that I was wrong in telling you that your first example was a valid X-Wing.

tarek, ronk: Am I right/wrong on this constraint?

[hobiwan]

hobiwan: I'm sorry to have presented such a rudimentary explanation when I should have realized that you already have a strong grasp of Fish. I missed the subtlety of your query.

No problem.

It took me awhile to realize what bothered me about your first example. Then I realized that it only has one candidate cell in c5. To the best of my knowledge, every Base/Cover Sector must have at least two candidate cells. I don't know if it's assumed or if it's been documented someplace. If it's documented, it's probably in a very old thread. Maybe even in the Programmers Forum.

Anyway, this explains why my examples don't include your first example. It also means that I was wrong in telling you that your first example was a valid X-Wing.

Sudopedia has that restriction but the mini glossary has not. IMO this is a progress because it makes things easier. From a practical viewpoint, why should you bother wether the fish degenerates as long as it makes the same eliminations?

IMO, the term sashimi is redundant. Its constant use has plagued fish. I'm not sure why I feel like this, but I'm thinking that others may feel the same .

Definitly! But redefining the term as you propose might open another pandora's box and give you even more trouble. I stand with what I said before:

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remove the term sashimi from the section "Shapes of fish"
add a line that says that any finned fish that degenerates without the fins may be called sashimi instead of finned

[edit: added "instead of finned" to make my intentions clearer]

[Pat]

due to the beautiful simplicity of your fish definition,
the following

Code: Select all

 . . . | . / . | . / .
 * * * | * X * | * X *
 . . . | . / . | . / .
 ------+-------+------
 . . . | . / . | . / .
 . . . | . / . | . / .
 . . . | . / . | . / .
 ------+-------+------
 * * * | * / * | * X *
 . . . | . / . | . / .
 . . . | . / . | . / .



is a well-formed basic X-wing

yes it is.
i like the beautiful simplicity of the fish definition.
both of these statements are true --

it is an X-wing.
it is a degenerate X-wing.