The New Sudoku Players' Forum

[Luke]

First off , I'd like to say it's kinda nice to see the energy that has built up lately in this little niche we have here. New contributors, re-emerging players, discussions and controversies ... this is more like it. Things seemed to pick up when Dan trotted out the light-hearted alliteration gimmick, so I give him credit for the uptick in interest. Thanks, buddy ... it never hurts to have a little fun.

Not quite so fun:

SteveG48 wrote: You would spot that before glomming on to a simple DP possible?

I always look for moves that don't rely on uniqueness before those that do. Have look here http://sudopedia.enjoysudoku.com/Uniqueness_Controversy.html

Really? ??Realllllly?? I know you are just expressing your own preferences, but really?

It's almost 2014. This war has been over for eons and I thought it was widely accepted who won. It just seems wrong to passive-aggressively warn off emerging players from uniqueness strategies that are so entrenched in today's solving. Especially with intractable zealots like me around ...

IMO, a better reason for looking for basic chains before uniqueness-based methods is that when it comes to solving, simplicity and elegance go hand-in-hand.

What's up, Don! Great to see your name back here and also good to see you standing up for uniqueness.

Still, you seem to imply that somehow an inference derived from uniqueness constraints is less "elegant." I don't buy that either, by a long shot. A unique or deadly or impossible pattern stands as a pure and unmovable rock, by itself the very definition of logical precision and elegance. It might be large, or sprawling around the grid, or obscure, or well hidden, but none of that changes its heartless beauty.

While the uniqueness pattern itself can never be inelegant, its use can certainly be. If the "outs" of a pattern are followed around the grid in lengthy and convoluted chains, then I might agree that a line is crossed. Esp if the puzzle is not so tough.

On the other hand, the most complicated, ugly looking beast of an AUR, MUG, BUG or WHUG-ever can reveal inferences that solve or advance a puzzle more simply than the prettiest little wing.

I think we should judge the elegance of DP use by the inferences it produces. Once that inference gets built into my chain, I no longer even see the DP. I think players confuse the fact that it's usually messy to notate a DP move, and that makes DPs themselves messy and therefore undesirable and ... (I can hardly say it) ... "inelegant."

[SteveG48]

IMO, a better reason for looking for basic chains before uniqueness-based methods is that when it comes to solving, simplicity and elegance go hand-in-hand.

What's up, Don! Great to see your name back here and also good to see you standing up for uniqueness.

Still, you seem to imply that somehow an inference derived from uniqueness constraints is less "elegant." I don't buy that either, by a long shot.

I don't either. To me, something like a type 1 UR is both simple and elegant.

As for the controversy itself, it seems to me that if you apply a uniqueness argument and it leads to a solution, then the solution speaks for itself, but to each his own.

[DonM]

Still, you seem to imply that somehow an inference derived from uniqueness constraints is less "elegant."... etc. etc.

Hi Luke, my friend,

I think you're reading more into my comment than was implied, particularly since it (my comment) isn't all that relevant in an environment where all the puzzles are 'one-steppers'. And while I believe my comments about uniqueness are based on fact, not opinion, the comment relating to elegance (added more as an afterthought than anything) has 'IMO' at the beginning.

My solving experience was more in an environment of solving puzzles which only very rarely were one-steppers. One was solving up against 6-8 very clever solvers and there was always a sense of constructive competitiveness. There were several discussions on what were the more elegant solutions and a consensus developed that the 'simpler' solutions trumped the more complex for a given puzzle.

Thus, a single chain with 2 strong links was more elegant than one with 4 strong links for a given elimination. (Steve K indicated the number of strong links after each of his chains.) A basic chain was more elegant than one with an 'almost' (eg. ALS) construct for a given elimination. A solution for a given puzzle without using a net was more elegant than one that did although even there, we probably admired a one-step net-based solution over one using several basic chains. In general, the solver who could bring down the rhino with a BB gun got a bigger slap on the back than the one that used a gattling gun.

Thus, I find a simple chain for a given elimination to be more elegant than one using uniqueness, keeping in mind that the one with uniqueness may still be very clever. But all of this is just my opinion and is based on how I challenge myself when solving a difficult puzzle.

[Luke]

Remember Udosuk? I once asked him, what is elegance, anyways? His reply:

My definition of elegance is:

Using the minimal amount of information and the simplest possible logic, create the maximal amount of deductions.

Pretty good, huh?
He went on to add this, though:

In other words, moves that use fewer cells (small ALSs vs long chains), less assumptions (e.g. no uniqueness), less implications (e.g. simple chains vs nets, "memory"), more eliminations (e.g. wings, fishes) are considered by me as more elegant than others.

Damn, he had to go ruin it with "Less assumptions (e.g. no uniqueness)," jajaja!

Don, I enjoyed those competitions on Eureka. Near the end the puzzles got easier, esp in the Eureka Challenge series. Those later SE 7.3 to 7.8 puzzles could be shot down by the right one-stepper, often a uniqueness based move.

I won't beat up these fun daily one-steppers with things like AAICs, kraken cell/row/box, elaborate nets, et al. I learned that from you, more than anyone else. But gloves are off for uniqueness, DPs, impossibles, AALS et al on any puzzle at any time with any difficulty high or low.

Viva la diferencia, I guess!

--------------------------------------------
An actual American domestic exchange, on this, the day after Thanksgiving.

Wifey: "Will you go shopping with me today?"
Me: "On Black Effing Friday? Why would you even ask me that??"
Wifey: "I need someone to carry my bags."
Me: <Covering eyes, shaking head>

[eleven]

As for the controversy itself, it seems to me that if you apply a uniqueness argument and it leads to a solution, then the solution speaks for itself, but to each his own.

Nice said However if the puzzle has multiple solutions, you might make a wrong elimination, and don't find any solution - you will hate the puzzle provider then ...

[SteveG48]

As for the controversy itself, it seems to me that if you apply a uniqueness argument and it leads to a solution, then the solution speaks for itself, but to each his own.

Nice said However if the puzzle has multiple solutions, you might make a wrong elimination, and don't find any solution - you will hate the puzzle provider then ...

Or you may find one solution and miss the fact that there are others.

[DonM]

But gloves are off for uniqueness, DPs, impossibles, AALS et al on any puzzle at any time with any difficulty high or low.

Viva la diferencia, I guess!

Well, glad to see the passion is still there!