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How to say "Your're toast" ?

 
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nataraj



Joined: 03 Aug 2007
Posts: 1029
Location: Vienna, Austria

PostPosted: Wed Nov 26, 2008 11:21 pm    Post subject: How to say "Your're toast" ? Reply with quote

Do a google search on "how to say i love you" and get
Results 1 - 10 of about 1,600,000 for "how to say i love you". (0.18 seconds)

That's an impressive number: 1.6 million hits

How to write: because of .... the pincers r1c7 and r8c6 eliminate 5 from both r1c6 and r8c7?
(in a concise and universally understood manner?)

In my recent (couple of weeks' worth) posts, I've taken the liberty to use the "=" notation, which describes a strong link (which, incidentally, is just about the same as "pincers" - it's either one or the other or both) to give a shorthand description of those "pincer"-oriented eliminations like xy-wing, w-wing and m-wing.

I'm sure you've noticed and I'm equally sure many of you guys (n gals) have an opinion about this.

In order to describe a w-wing, which uses two {8,9} cells that each see the ends of a strong link on 8 in row 9, I write

w-wing (9)r1c1=r6c6 (via strong link ( 8 ) in row 9);

For an xy-wing, I might write:

xy-wing (1) r6c8=r5c2 (13-35-51); r6c1<>1

which means there is an xy-wing with pincers r6c8 and r5c2 and it removes 1 from r6c1. I leave the task of figuring out the pivot to the reader.

In both cases I give a hint / explanation of how it is done in parentheses

My question now to this exquisite group of solvers: do you think that this shorthand notation is appropriate? Is it useful? Is there already a well established way of writing down these patterns? Am I completely off my rocker Rolling Eyes?)

To me, this notation has a few advantages:
- it focusses on the "active" cells (the pincers) and not on the helper cells (pivot ....)
- it makes a clear statement about which candidate in the pincer cells is making the elimination and which cells are the helpers (think of "w-wing 27 in r1c1 and r9c9 ...")
- it can be easily used to extend the pattern by transporting one or both of the pincer cells.
- it is nothing new but only uses a well established symbol (=) exactly in the meaning it has in other sudoku notations.
- and ... I think it is much more accessible than the pure AIC or nice loop notations for the same situations.

It has some disadvantages, too:
x-wing, swordfish etc ... are not pincer based and cannot be described by this notation

xyz-wing would need something like (8)r1c1=np(...).... which is really awkward

What do you think? Does the world need another bit of formal language at all? Especially in a relaxed site like dailysudoku.com?

Hit me ...
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keith



Joined: 19 Sep 2005
Posts: 3175
Location: near Detroit, Michigan, USA

PostPosted: Thu Nov 27, 2008 2:58 am    Post subject: Reply with quote

Nataraj,

I've been thinking about this also.

My own inclination is to have a notation that describes the logic. With side notes to describe the cell location in any puzzle.

Or, as I often use, notation of the cells in a graphic of the puzzle, with a written explanation, eg., "W-wing <15> with strong link in C3". In the graphic we would have the cells labelled a, b, c, d, with the eliminations shown by -.

I think the more important point is: What notation do you use for a link, and what do you mean by a link?

Here is my proposal:

Two cells A, B, have the same candidate X. "True" means a cell is "X".

= is a strong link. One of A or B is true. And, one is false.

- is a weak link. If A is true, B is false, and vice-versa. Both may be false.

I propose:

% is an XY-link, or a W-link, or your pincer link. One, or both, of A and B is true.

I think the only other case is neither A or B is true, in which case they are eliminated, and no notation is needed.

Best wishes,

Keith


Last edited by keith on Thu Nov 27, 2008 3:09 am; edited 1 time in total
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Marty R.



Joined: 12 Feb 2006
Posts: 5162
Location: Rochester, NY, USA

PostPosted: Thu Nov 27, 2008 2:59 am    Post subject: Reply with quote

While I wouldn't compare most of us to accomplished writers, nevertheless, we are writers when we post. Any good writer will (or should) determine his target audience and write accordingly.

If you're interested in addressing only the cognoscenti, then write only in Eureka notation, or whatever it's called. If you want to address us poor souls who aren't that advanced, then write a clear description of your technique.

However, the two aren't mutually exclusive. You can write something like, "I used a Kraken Franken Jane de Coq on 47, eliminating such and such. Here's how it looks in Eureka."

I stated recently that I'm not a notation reader. But I've seen a number of replies that were written in notation only that I would've liked to know the technique but was left in the dark. That's not the end of the world, but it tells me who the writer wanted to reach.

If I write about an XY-Wing, I'll say "XY-Wing on 153 pivoted in r5c8." Not that others would necessarily know this, but the XY are always the first two digits of my three. Virtually everyone who reads this forum knows how to find the other two cells and determine the pincers.

Quote:
My question now to this exquisite group of solvers: do you think that this shorthand notation is appropriate? Is it useful?

It certainly is, to at least some. But again, if you give people a choice by supplementing it with a description, then you reach the maximum number of readers.

But I've rambled on more than enough. If you make the determination mentioned in my first paragraph, you'll have answered your questions to a large degree. Very Happy
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Thu Nov 27, 2008 3:12 am    Post subject: Reply with quote

To me, it doesn't matter how a person presents an elimination .. until I don't understand it. When I don't understand, then concise notation is a much easier way for me to follow what's happening -- even if I have to deciper the notation, which I've done all too many times.

From my solver:

Code:
          pivot/pincer+pincer   value   eliminations

XY-Wing  [r1c2]/[r1c4]+[r2c1]   <> 4    [r1c3],[r2c4]
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