The New Sudoku Players' Forum

[champagne]

try to find the logic behind.

Hi eleven and happy new year

I had a look to that thread and I was first surprised to see an XSUDO picture.

I recognised an EXOCET and had the feeling that it was Golden Nugget.

For sure, Exocets, but also huge rank 0 logics have no transcription in chains.

This is basically the reason why they appear in the so called hardest puzzles rated using a set of rules based on chains (like Sudoku Explainer but not only that one).

Regarding the rules to write the justification of an elimination in chain mode, I have no clear Idea, but I would say that to-day I am mostly using left driven expansion.

This does not prevent IMO to try to have writing rules for pure chains. I am sure I would use them if they are clearly defined somewhere.

Denis Berthier has rules to write such chains, but I am using more objects (XWings, Kites, URs) then him, so I prefer to develop the expansion in Sudoku Explainer mode (simplified).

[DonM]

If you are asking someone to use standardized notation, which I agree is a good idea, it is important that there be some agreement about what the standard actually is and some way to access/refer to the contents of that agreement. If the Eureka forum posts explaining the standard no longer exist, it is important that some appropriate definition of how notation should be written exist somewhere else, otherwise it is no longer possible to use that format as a standard. Without a reference, new users have no way to learn how to use it and experienced users have no way to double check if they actually remember one of the more obscure aspects of the standard correctly.

I have seen some basic overviews of Eureka notation, for example http://www.sudocue.net/eureka-notation.php or http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=6708, but I suspect those descriptions aren't really complete enough to serve as a standard.

I think it's safe to say that 'basic' standardized Eureka notation is described pretty clearly in the sudocue.net link above. The present discussion (as far as I'm concerned) has been about the benefits of solvers adhering to some kind of standard and the importance of using a reasonably clear and accurate presentation of basic and common constructs such as the ALS. This shouldn't be all that difficult or vague- it's not rocket science- and I think the solvers who have been around for a number of years and still put up notated chains present good examples as to how these basic patterns should be notated.

On the other hand, I'm not so concerned with 'obscure aspects' of notation which I take to mean the more complex patterns having to do with various deadly patterns, Almost AICs etc. They will probably always be open to some variation. Overall, I think that discussion about notation is important where the aim is to have people using reasonably similar notation so that they can understand and appreciate each other's solutions. I don't agree with those who think that such a discussion is a waste of time.

[David P Bird]

To produce a revised Eureka MK II standard is a daunting task which requires a general willingness to reach a compromise. The original conventions had to be expanded as different types of patterns we introduced, few of which have appeared in this thread, and these aspects should also be considered.

Don as you are now in the driving seat and as I've had limited success in this area before, I'll stay out of it. Now don't take this personally this time, but from the Sudocue link "A strong link exists when the pair of candidates are the last 2 remaining candidates in the constraint" describes a conjugate link, not a strong one. Agreed, the concepts aren't rocket science but expressing them properly takes care, and shouldn’t be underestimated.

Eleven You are making mischief. The notation for your position from the Golden Nugget puzzle is
(1247)JExocet:r12c7,r4c8,r7c9 => r7c9 <> 3
The pattern elements described only cover enough elements for the rest of the pattern to be located to verify it complies with the full definition given here. This gives a short proof which, like the proof of a UR, can't be expressed as a linear AIC.

If the pattern exists in an Almost form, then eliminations that would result if either the pattern were true or if the disrupting candidate was true can be made. In that case it could be included as a node in an AIC.

[champagne]

Eleven You are making mischief. The notation for your position from the Golden Nugget puzzle is
(1247)JExocet:r12c7,r4c8,r7c9 => r7c9 <> 3

Hi David,

I have to confess that I did not imagine that notation

I agree and something similar could be done for any rank 0 logic. I understand why you write somewhere that writing the rules is a huge task. I am already lost with many simpler pattern names used here and there (M_Wings W_Wings Finned.....)

[eleven]

(1247)JExocet:r12c7,r4c8,r7c9 => r7c9 <> 3

Hehe, well done. (1c24,2c14,4c26,7c16)

[RichardGoodrich]

If you are asking someone to use standardized notation, which I agree is a good idea, it is important that there be some agreement about what the standard actually is and some way to access/refer to the contents of that agreement. If the Eureka forum posts explaining the standard no longer exist, it is important that some appropriate definition of how notation should be written exist somewhere else, otherwise it is no longer possible to use that format as a standard. Without a reference, new users have no way to learn how to use it and experienced users have no way to double check if they actually remember one of the more obscure aspects of the standard correctly.

I have seen some basic overviews of Eureka notation, for example http://www.sudocue.net/eureka-notation.php or http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=6708, but I suspect those descriptions aren't really complete enough to serve as a standard.

As a newbie, I agree. I am bold enough - maybe too bold - to think I understand Bob Hanson's Sudoku Assistant approach to 3D Medusa, but I can't get a canonical explanation of Eureka notation. I have read some helpful comments on it and I suspect that the idea came from David Eppstein's paper on graph theory which I think I found referenced in this forum.

Shalom, Richard