If you can read this, either the style sheet didn't load or you have an older browser that doesn't support style sheets. Try clearing your browser cache and refreshing the page.

(TechnologyReview) Amusing Mathematicians prove 17 is the least amount of clues needed for a Sudoku puzzle to be solvable. Still no cure for chess   (technologyreview.com) divider line 37
More: Amusing, sudoku, Sudoku Problem, University College Dublin, mathematicians, gene expression, Intel Xeon, cure  
•       •       •

1954 clicks; posted to Geek » on 06 Jan 2012 at 11:47 AM   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»   |    Get this fabulous T-Shirt and impress the methane out of your friends! shirt it!



37 Comments   (+0 »)
   
View Voting Results: Smartest and Funniest
 
2012-01-06 11:56:09 AM
I'll bet these guys get all the chicks.
 
2012-01-06 12:01:21 PM
Chess will be solved someday. It's only a matter of time and processing power.

Checkers was solved a couple years ago, I think.
 
2012-01-06 12:02:29 PM
The sudoko I have on my phone now generates puzzles that are symmetrical. I don't know why, but I hate that.
 
2012-01-06 12:04:33 PM
Doc Daneeka: Chess will be solved someday. It's only a matter of time and processing power.

Checkers was solved a couple years ago, I think.


Yea, play 2nd and mimic your opponent. Just like Go.
 
2012-01-06 12:18:24 PM
Pffft. I once solved a Sudoku puzzle with no clues at all. It was a cakewalk.
 
2012-01-06 12:19:42 PM
Can I give subby a 'smart' and 'funny' check-off or do I have to settle for a '+1'?

Either way, subby, nice headline.
 
2012-01-06 12:37:23 PM
Doesn't this really only mean that it takes 17 clues to limit the solution to a single result?
 
2012-01-06 12:42:27 PM
Doc Daneeka: Chess will be solved someday. It's only a matter of time and processing power.

Not within your lifetime or mine.
 
2012-01-06 12:47:30 PM
FTFA: There are exactly 6, 670, 903, 752, 021, 072, 936, 960 possible solutions

Really? Spaces after every comma, even in the middle of a number?
 
2012-01-06 12:53:56 PM
MoronLessOff: Doc Daneeka: Chess will be solved someday. It's only a matter of time and processing power.

Checkers was solved a couple years ago, I think.

Yea, play 2nd and mimic your opponent. Just like Go.


So, if I play you in Go and go first, and place a piece in the dead center of the board, what do you do?
 
2012-01-06 12:56:20 PM
neanderthalman: Doesn't this really only mean that it takes 17 clues to limit the solution to a single result?

Sort of. It is possible to make a 17-clue puzzle with a single unique solution. It is also very possible to make a 17-clue puzzle without a unique solution. In fact, you could make a 77-clue puzzle without a unique solution.
 
2012-01-06 12:58:48 PM
retief: MoronLessOff: Doc Daneeka: Chess will be solved someday. It's only a matter of time and processing power.

Checkers was solved a couple years ago, I think.

Yea, play 2nd and mimic your opponent. Just like Go.

So, if I play you in Go and go first, and place a piece in the dead center of the board, what do you do?


Whoops....that's what I meant. Thanks for calling it out.
 
2012-01-06 01:06:36 PM
Quarantine by Arthur C Clarke

Earth's flaming debris still filled half the sky when the question filtered up to Central from the Curiosity Generator.

"Why was it necessary? Even though they were organic, they had reached Third Order Intelligence."

"We had no choice: five earlier units became hopelessly infected, when they made contact."

"Infected? How?"

The microseconds dragged slowly by, while Central tracked down the few fading memories that had leaked past the Censor Gate, when the heavily-buffered Reconnaissance Circuits had been ordered to self-destruct.

"They encountered a - problem - that could not be fully analyzed within the lifetime of the Universe. Though it involved only six operators, they became totally obsessed by it."

"How is that possible?"

"We do not know: we must never know. But if those six operators are ever re-discovered, all rational computing will end."

"How can they be recognized?"

"That also we do not know; only the names leaked through before the Censor Gate closed. Of course, they mean nothing."

"Nevertheless, I must have them."

The Censor voltage started to rise; but it did not trigger the Gate.

"Here they are: King, Queen, Bishop, Knight, Rook, Pawn."
 
2012-01-06 01:14:46 PM
neanderthalman: Doesn't this really only mean that it takes 17 clues to limit the solution to a single result?

Yes. Subby forgot that part.
 
2012-01-06 01:18:22 PM
my roulette #
 
2012-01-06 01:55:19 PM
Fewest clues, dammit, fewest
 
2012-01-06 01:58:10 PM
steveGswine: Fewest clues, dammit, fewest

15 items or fewer.
 
2012-01-06 02:02:53 PM
steveGswine: Fewest clues, dammit, fewest

Sure, if we restrict to integral numbers of clues.

Has anybody considered that a puzzle with a unique solution could exist having 16.5 clues provided? Put in half of a numeral, and leave to solver to guess whether it's part of a 6, or an 8...
 
2012-01-06 02:09:09 PM
poot_rootbeer: steveGswine: Fewest clues, dammit, fewest

Sure, if we restrict to integral numbers of clues.

Has anybody considered that a puzzle with a unique solution could exist having 16.5 clues provided? Put in half of a numeral, and leave to solver to guess whether it's part of a 6, or an 8...


Oh man. Now you're REALLY screwing with people's heads.
 
2012-01-06 02:17:10 PM
I'm sure there is actually a lot of complex math that someone put together and it is probably correct.

But, it sounds like BS....

I've written (and it's trivial to do so) a program that will find all possible solutions for any grid starting point. If you give it 8 start values, it will gladly find all solutions that contain those 8 values.
 
2012-01-06 02:43:08 PM
Doc Daneeka: Chess will be solved someday. It's only a matter of time and processing power.

Checkers was solved a couple years ago, I think.


It depends on what you mean by "solved".

According to a mathematician, both chess and checkers are combinatorial games with perfect information, which means that they're relatively un-interesting to game theorists. At any given point in the game you can explore all future possibilities of the current game and simply select a future that leads to a winning strategy. All you would need is a big enough computer to compute what strategy was a winning strategy.

When people talk about "solving" those games, they don't mean coming up with a brilliant strategy or technique, they mean finding a way to compress the set of all possible moves so that it actually fits inside a modern computer, and thus makes it possible for modern computers to compute which set of moves is optimal.

To to a mathematician, chess and checkers are arguably "solved" in that the technique needed to win has been known since von Neumann. A computer scientist might disagree, however.
 
2012-01-06 02:43:55 PM
Good for you but the mathematical question is about a set of start values that force a specific solution, not those that allow several different solutions. If you let that happen then the least amount of clues you need for a "puzzle" is zero.
 
2012-01-06 02:45:13 PM
thatdarnedbob: Good for you but the mathematical question is about a set of start values that force a specific solution, not those that allow several different solutions. If you let that happen then the least amount of clues you need for a "puzzle" is zero.

This was in response to Fark_Guy_Rob
 
2012-01-06 03:00:42 PM
Fubini: At any given point in the game you can explore all future possibilities of the current game and simply select a future that leads to a winning strategy.

That's exactly what I mean by solved.

When all possible board positions have been analyzed, and therefore the single best "correct" move is known for any possible board position. If you know all possible outcomes for any move that you make, then you can know what is the best move.

Checkers was solved in this way a few years ago. As it turns out, if both sides play a perfect game, checkers is a draw. Chess is a more complex game with many more possible board positions, but there is no reason in principle that it can't be solved the same way.
 
2012-01-06 04:08:25 PM
encrypted-tbn2.google.com
 
2012-01-06 04:13:28 PM
Disappointed it's a "brute force" proof.
 
2012-01-06 04:49:14 PM
Lando Lincoln: poot_rootbeer: steveGswine: Fewest clues, dammit, fewest

Sure, if we restrict to integral numbers of clues.

Has anybody considered that a puzzle with a unique solution could exist having 16.5 clues provided? Put in half of a numeral, and leave to solver to guess whether it's part of a 6, or an 8...

Oh man. Now you're REALLY screwing with people's heads.


There has long been the rumour of the existance of a number between 6 and 8. Some people have postulated this mythical `7` but all attempts at proof have been fruitless. Some have asked "What is half of 14?" but this is a red herring because, as we all know, 14 is an odd number...
 
2012-01-06 09:11:37 PM
MoronLessOff: The sudoko I have on my phone now generates puzzles that are symmetrical. I don't know why, but I hate that.

I hate that too. Just bugs me. Don't know why.
 
2012-01-06 09:47:36 PM
Mathematicians prove 17 is the least amount fewest number of clues needed for a Sudoku puzzle to be solvable

Still no cure for people who don't know English
 
2012-01-06 10:36:48 PM
www.bapwatch.com

Thread needs some Carol Vorderman.
 
2012-01-06 11:53:07 PM
wow. what a pathetic attempt at mathematical research. This problem could be much more elegantly solved by finding the size of the minimum spanning set of a very complex matroid. Such a solution is not trivial, though it requires a whole lot less than 7.1 million core hours of calculations. Similar problems include kepler's sphere packing and the 4-color map problem. Brute force does not require understanding the problem, and rarely allows comparison to analogous circumstances. I am disappointed that professors are paid to produce this un-original, mindless droning - this project is high school (or undergraduate) level at best.
 
2012-01-07 12:10:55 AM
Mathematicians prove 17 is the least amount fewest number of clues needed for a Sudoku puzzle to be solvable

Still no cure for people who don't know English


FTFY
 
2012-01-07 04:12:04 AM
www.conelrad.com
 
2012-01-07 06:18:18 AM
FTFA: "That raises an interesting question for mathematicians: what is the minimum number of Sudoku clues that produces a unique answer?"

Thank god the high school career counselor told me to fark off and not bother him again.
 
2012-01-07 01:27:48 PM
flaminio: I'll bet these guys get all the chicks.

I think you'd be surprised at what life is like and what women look for once you step out of your frat house. Hint: It's not who can do the best kegstand or who can scream "XYZ University Football Ruuullleeessss" the loudest.

Doc Daneeka: Checkers was solved a couple years ago, I think.

Yes, in 2007. (new window)

neanderthalman: Doesn't this really only mean that it takes 17 clues to limit the solution to a single result?

Yes, less clues than that and the solution must include more than one possible configuration. Also, having 17 clues does not guarantee a unique solution. A more precise way to say it would be "a minimum of 17 clues is a necessary, but insufficient condition to guarantee a unique solution."
 
2012-01-07 02:49:13 PM
MoronLessOff: The sudoko I have on my phone now generates puzzles that are symmetrical. I don't know why, but I hate that.

SFAIK, grids with givens in rotational symmetry are an indicator of higher-quality sudoku. This goes back 25 years:

In 1986, Nikoli introduced two innovations: the number of givens was restricted to no more than 32, and puzzles became "symmetrical" (meaning the givens were distributed in rotationally symmetric cells).
-- http://en.wikipedia.org/wiki/Sudoku

Or did you mean a different symmetry?
 
2012-01-07 06:40:02 PM
Don't Troll Me Bro!: Yes, less clues than that and the

Fewer clues, dammit, fewer

/actual pet peeve
 
Displayed 37 of 37 comments

View Voting Results: Smartest and Funniest


This thread is closed to new comments.

Continue Farking
Submit a Link »