The New Sudoku Players' Forum

by **ronk** » Mon Jun 28, 2010 4:33 pm

daj95376 wrote:Previously, I had mentioned a "Dual Kraken X-Wing" configuration and Mike Barker applied it to NoFish1.

I now realize that a (remotely) finned Jellyfish contains both X-Wing patterns.
Code: Select all
finned Jellyfish c1346\r2378 w/remote fins r5c16,r6c34 => r3c5<>5 +-----------------------------------+ | . . . | . . . | . 5 . | | . 5 . | *5 5 *5 | . . . | | *5 . *5 | . -5 *5 | . . . | |-----------+-----------+-----------| | . . . | . . . | 5 . . | | #5 5 . | . . #5 | . . . | | . . #5 | #5 5 . | . . . | |-----------+-----------+-----------| | *5 5 . | *5 . . | . . . | | . 5 *5 | . . *5 | . . . | | . . . | . . . | . . 5 | +-----------------------------------+

If unfinned Jellyfish is true, then r3c5<>5.

If either r5c1|r6c4 is true, then the Jellyfish reduces to finned X-Wing c36\r38 => r3c5<>5.

If either r5c6|r6c3 is true, then the Jellyfish reduces to Sashimi X-Wing c14\r37 => r3c5<>5.

I agree that either the finned x-wing or the sashimi x-wing must be true, but I don't think this means the overall pattern is a jellyfish. Although other cover sets exist, the overall pattern has four base sets (c1346) and eight cover sets (r35678b245). The normal jellyfish would have either four, five or six cover sets.

......

Additionally, this example could be considered a poster child for the NoFish class of template eliminations.

Code: Select all: . . . | . . . | . 5 . . 5 . | g5 5 g5 | . . . g5 . g5 | . -5 g5 | . . . ---------+----------+---------- . . . | . . . | 5 . . *5 5 . | . . *5 | . . . . . *5 | *5 5 . | . . . ---------+----------+---------- *5 5 . | *5 . . | . . . . 5 *5 | . . *5 | . . . . . . | . . . | . . 5

If all the guardians r2c46 and r3c136 -- marked (g) -- were false, there would be an impossible jellyfish in c1346. Therefore, at least one of the guardians must be true and r3c5<>5, since it sees all the guardians.

Perhaps the subject of allowing fish to have remote fins should be revisited. Obi-Wahn didn't allow them, my generalized-fish-finder (GFF) doesn't use them and, the last I heard, your GFF didn't use them either.

by **tarek** » Sat Jul 03, 2010 10:51 am

This is the NoFish list that I originally posted on the old forum. It Follows Obi-Wahn's 21 puzzles posted in his original NoFish List.

The puzzles solution path will start at the NoFish move. These eliminations were verified through template eliminations. Thanks to Danny & blue for re-verifyiny the eliminations with corrections.

Thanks for ronk & ttt for saving a copy that helped bringing this back.

[EDIT: List corrections updated]

Nofish022-563: Show

by **daj95376** » Tue Feb 25, 2014 1:08 am

To make a long story short, my search for Kraken fish examples of Broken Wings took an interesting turn when I discovered an old post of mine and I updated the logic a bit.

Code: Select all: unfinned Jellyfish r1245/c1279 (exemplar) -- eliminations legitimate +-----------------------------------------------+ | X X / | / / / | X / X | | X X / | / / / | X / X | | * * . | . . . | * . * | |---------------+---------------+---------------| | X X / | / / / | X / X | | X X / | / / / | X / X | | * * . | . . . | * . * | |---------------+---------------+---------------| | * * . | . . . | * . * | | * * . | . . . | * . * | | * * . | . . . | * . * | +-----------------------------------------------+

Code: Select all: unfinned Jellyfish r1245/c1279 and "~" cells empty in candidate grid -- Broken Wing pattern -- eliminations can not all be false +-----------------------------------------------+ | ~ X / | / / / | ~ / X | | X ~ / | / / / | X / ~ | | * * . | . . . | * . * | |---------------+---------------+---------------| | X ~ / | / / / | ~ / X | | ~ X / | / / / | X / ~ | | * * . | . . . | * . * | |---------------+---------------+---------------| | * * . | . . . | * . * | | * * . | . . . | * . * | | * * . | . . . | * . * | +-----------------------------------------------+

Code: Select all: finned Jellyfish r1245/c1279 and "~" cells empty in candidate grid -- potential Broken Wing pattern -- eliminations can not all be false -- at least one fin cell must be true (valid assumption ???) +-----------------------------------------------+ | ~ X / | / / / | ~ / X | | X ~ / | / # / | X / ~ | | * * . | . . . | * . * | |---------------+---------------+---------------| | X ~ / | # / / | ~ / X | | ~ X / | / / # | X / ~ | | * * . | . . . | * . * | |---------------+---------------+---------------| | * * . | . . . | * . * | | * * . | . . . | * . * | | * * . | . . . | * . * | +-----------------------------------------------+

Now, welcome to ...

Code: Select all: Obi-Wahn NoFish #6: +-----------------------------------+ | . X5 . | . . . | . . X5 | | X5 . . | . #5 . | X5 . . | | . 5 . | . 5 5 | . . 5 | |-----------+-----------+-----------| | X5 . . | #5 . . | . . X5 | | . X5 . | . . #5 | X5 . . | | 5 . . | . -5 . | 5 . . | |-----------+-----------+-----------| | . . . | . . . | . 5 . | | . . 5 | . . . | . . . | | . . . | 5 5 5 | . . . | +-----------------------------------+

What makes this particularly interesting is that the potential Jellyfish never performs -5r6c5. However, since 5r6c5 is a peer of all three fin cells, then its elimination can be justified (I hope).

I now have an example of a potential Kraken Jellyfish that performs a Broken Wing elimination for NoFish6, but I'm not sure what to do with it.

Whew!!!

Now, someone will tell me that this has already been determined ... and I must have forgotten about it.

by **ronk** » Thu Feb 27, 2014 2:16 am

daj95376 wrote:What makes this particularly interesting is that the Jellyfish never performs -5r6c5. However, since 5r6c5 is a peer of all three fin cells, then its elimination can be justified (I hope).

I now have an example of a Kraken Jellyfish that performs a Broken Wing elimination for NoFish6, but I'm not sure what to do with it.

Where did Mike Barker say an unfinned kraken fish didn't need a cover sector (weak link) that included the elimination candidate? I've forgotten a lot of stuff over the years, but that not being a requirement is news to me today.

by **daj95376** » Thu Feb 27, 2014 6:41 am

ronk wrote:Where did Mike Barker say an unfinned kraken fish didn't need a cover sector (weak link) that included the elimination candidate? I've forgotten a lot of stuff over the years, but that not being a requirement is news to me today.

I'm having trouble following your wording. However, ...

My elimination does not result from a fish pattern because it does not meet the EE and PE requirements in TUFG. It results from the invalidity of the occupied vertices in the candidate grid for the potential fish pattern; thus forcing at least one fin cell to be true.

I've updated my post above to include "potential".

by **Sudtyro2** » Thu Feb 27, 2014 11:02 pm

DAJ's finned Jellyfish solution of NoFish#6 is very interesting because it reveals a major flaw in my understanding of the basic Fin/Fish exclusion rules. My thinking originally was that one could always assume a Fish=Fin(s) strong-link rule.

This was based in part on the current UFG head post that states...
"In an NxN finned fish:
If the unfinned fish component is false, then at least one of the fins is true.
If all the fins are false, then the unfinned fish component is true."

I interpreted these statements as a Fish=Fin(s) strong-link rule. However, the second statement does not hold for DAJ's finned Jellyfish, because the unfinned Jellyfish is already false. If the three fin cells are all set false, then the unfinned Jellyfish is still false! We know this because one can quickly run an AIC through the X-cells that immediately leads to a contradiction. This Jellyfish pattern, which may be a Broken Wing of sorts, therefore does not have a valid solution. Note, however, that all three fin cells are peers of the exclusion cell.

I think JC Van Hay summed it up nicely when he wrote (via PM):
“Just a warning: you cannot write Fish=Fin(s)!
All you can say about a Finned Fish in a valid puzzle: Either the Fish has at least one solution or it has no solution.
In the first case, a candidate "seeing" [both] the Fish and the Fin(s) is excluded. While in the second case, a candidate "seeing" the Fin(s) is excluded.
So, you can only write Fish=Fin(s) in the first case (Fish false => Fin(s) true and Fin(s) false => Fish true, depending on the solution of the base)!”

JC illustrated this argument based on one of his interpretations of the exclusion in DAJ's 7s grid. JC had developed an Xsudo-like SLG and then further analyzed the SLG, in UFG-style, as a finned Starfish. The Starfish had no solution, but the fins were all peers of the EE cell. His full UFG treatment is shown in the hidden text below. RE-EDIT to clarify which interpretation JC used for his analysis.

Perhaps JC's Starfish is also a Broken Wing of sorts.

Hidden Text: Show

by **eleven** » Fri Feb 28, 2014 9:20 am

Sudtyro2 wrote:Perhaps JC's Starfish is also a Broken Wing of sorts.

I am not familiar with your concepts, but
there is a broken wing (r1c25,r2c1,r9c15), where 7 of the 8 guardians see r9c5 directly.
If 7r1c9, a jellyfish in c1267 (r2679) is left, which would eliminate it.

by **daj95376** » Fri Feb 28, 2014 6:40 pm

Sudtyro2 wrote:This was based in part on the current UFG head post that states...
"In an NxN finned fish:
If the unfinned fish component is false, then at least one of the fins is true.
If all the fins are false, then the unfinned fish component is true."

There has been tons of rhetoric on defining fish patterns and deriving properties associated with them. I'm not going to tackle all of them.

In the case of your quote, I ask: How often have you seen someone present a finned fish pattern and categorically state that the unfinned fish component is true/false when applied to a candidate grid? Your quote is a derived property that's seldom seen the light in practical applications.

In almost all cases for NxN Fish-based solutions, the logic boils down to:

If a fish pattern is unfinned in the candidate grid, then all of the PE cells for the fish become EE cells in the candidate grid. Otherwise, the EE cells are derived from those PE cells that are seen, either directly or indirectly, by all fin cells.

If you further check TUFG's head post, you'll see that all PE (and thus EE) cells are in the cover set. That's because no one ever expected anyone to state anything categorically about the unfinned fish component!

In my example above, my EE cell is not a PE cell in the cover set for the unfinned fish component. That's because I was able to show that the fish pattern, when applied to the candidate grid, could not be true outside the fin cells.

eleven, nice find! Now, can you reduce it to an invalid unfinned fish component where the fin cells see the elimination cell?

by **eleven** » Fri Feb 28, 2014 7:12 pm

daj95376 wrote:eleven, nice find! Now, can you reduce it to an invalid unfinned fish component where the fin cells see the elimination cell?

Thanks. Sorry, as i said, i did not read already,what that is.
My elimination in fact is an almost kite combined with an almost jellyfish, but this a broken wing thread

Kite(7r1c25,r29c1)=7r1c9-7(r1c2,r3c7)=Jellyfish(7c1267r2679) => r9c5<>7

by **Sudtyro2** » Fri Feb 28, 2014 9:47 pm

DAJ,
As always, thx for the comments! I fully agree with what you are saying, but I couldn't help but notice that you have qualified your responses with terms like "potential," "seldom seen," "almost all cases," "how often," and "no one ever expected."

I find it curious that the UFG apparently makes no mention of the possibility of a false (invalid) unfinned Fish. And, outside of your finned-Jellyfish solution of NoFish#6, I had only been made aware of this possibility through JC Van Hay's UFG-style analysis of his SLG solution of your 7s grid. Maybe seldom seen, but impressive to this tyro, nevertheless. :!:

Edit to qualify the term "false."

by **David P Bird** » Sat Mar 01, 2014 12:26 am

Sudtyro2, please think about this:

A simple N-fish with no fins must provide truths in a set of N lines (say rows) which can only occupy cells in N cross-lines (say columns).

If that fish can only hold N-1 truths without producing a contradiction, then one row must be left without the fish digit which would make the puzzle invalid.

For the puzzle to be valid, to be able to satisfy that final row there must be an instance of the digit in a non-fish column - ie there must be a fin somewhere.

There is therefore a strong link between the fish cells holding N truths and the fin cells holding at least one truth.

From that start point the argument can be extended to base and cover sets to make this a general theorem.

DPB

by **yzfwsf** » Tue May 19, 2020 12:39 am

tarek wrote:This is the NoFish list that I originally posted on the old forum. It Follows Obi-Wahn's 21 puzzles posted in his original NoFish List.

The puzzles solution path will start at the NoFish move. These eliminations were verified through template eliminations. Thanks to Danny & blue for re-verifyiny the eliminations with corrections.

Thanks for ronk & ttt for saving a copy that helped bringing this back.

#029 have a broken wing as below

: broken-wing.png (29.74 KiB) Viewed 1204 times

by **SpAce** » Tue May 19, 2020 1:19 am

yzfwsf wrote:#029 have a broken wing as below

That's one hell of a broken wing (or oddagon)! One of the coolest things I've seen in a while. All ten guardians see the elimination directly.

Nice find, yzfwsf!

by **StrmCkr** » Tue May 19, 2020 8:42 am

Nice find, yzfwsf!

: Capture.PNG (63.73 KiB) Viewed 1189 times

now if its possible to convert that to an obifish

complex whale from xsudo C1379B58 / R1234679C456 {plus what ever else it dose to reduce it to a "complex" statement

by **Mauriès Robert** » Sat May 23, 2020 7:05 am

Hi All,

More classically with an anti-track and its bifurcations:

Code: Select all: ->1r6c4->1r4c9->1r4c3->1r9c5 => -1r2c5 | P'(1r123c4) : (-1b2p1478) => | ->1r6c7->1r1c56 => -1r2c5 | / ->(1r9c4->1r7c1) \ ->1r6c5 => -1r2c5

Sincerely
Robert

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