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A recent chess controversy

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Re: A recent chess controversy

#111

Post by alfiedotwtf »

permo-w wrote: post #62
wrsh07 wrote: post #10

Earlier quoted context omitted.

Yeah tbh it doesn't really go into chess-specific stats either You could look at a bunch of other metrics to identify cheating: how many errors/perfect moves^ and whether that's within the usual range. How well were the opponents playing? Etc If you consider that Nakamura might have been having a good day/week, was already stronger than his opponents, and some of them may have had bad games/days, you can change somet…

not really. this may be true for the average player, but as Magnus has explained multiple times, all he or another top GM would need to be near-unbeatable would be to check an engine in 1 or 2 critical positions per game. this essentially impossible to detect statistically. even if a cheater were to use an engine on every move, it would be trivial to just vary the engine used for each turn, vary the number of moves p…

What I don’t understand is that Hikaru can visualise in his head 30+ moves ahead from both plays, and yet he’s not better than Magnus?

Re: A recent chess controversy

#112

Post by lblume »

Scarblac wrote: post #65

I find it counter intuitive that the frequency of cheating matters. It's not something that happens randomly, people choose to. And if the #2 in the world decides to cheat it may be for different reasons than other players. But, of course he doesn't. He streams all his games and gives constant stream of consciousness commentary. If you can explain your top level moves live with seconds per move, you aren't cheating.

> It's not something that happens randomly, people choose to.

In Bayesian analysis, probability does not refer to the long-term frequency but instead to the subjective credence given to the event. Otherwise the probability of any one-off event would be undefinable. Therefore it follows that you need to have a prior over possible hypothesis in order to update your beliefs systematically according to the laws of probability theory. If it were known that Hikaru had cheated in the past, but typically does not, we might use a different prior (e.g. a Laplacian prior in this case); if we knew cheating to be dependent on some other measurable variable (e.g. the emotional state of the player), we would incorporate this into our evidence.

Re: A recent chess controversy

#113

Post by xrisk »

steppi wrote: post #108
indigodaddy wrote: post #91

Earlier quoted context omitted.

General statistical question. If we say extend the coin flip example distribution to say 10B times. Should/would we expect to see a streak of 100 or even 1000 in the distribution somewhere? Intuition alone tells me probably not for 1000 but a smallish chance for 100 (even if 10B in a row i would think a streak of 100 would be unlikely)

Your intuition's not bad. The expected value for the longest run of heads in N total flips of a fair coin is around log2(N) - 1 with a standard deviation that's approximately 1.873 plus a term that vanishes as N grows large. log2(10B) - 1 is approximately 32 and with that standard deviation, even a run of 100 in 10B flips is incredibly unlikely. For more info see Mark F. Schilling's paper, "The Longest Run of Heads"…

That’s a cool result, thanks for the link!

Re: A recent chess controversy

#114

Post by Archelaos »

bitshiftfaced wrote: post #70
sobiolite wrote: post #37

> Nakamura responded to Kramnik’s allegations by arguing that focusing on a particular streak while ignoring other games was cherry-picking. The researchers note that there’s a problem with this argument, too, as it violates the likelihood principle. This principle tells us the interpretation should only rely on the actual data observed, not the context in which it was collected. I don't quite understand this objecti…

I believe they're speaking within the scope of the Bayesian analysis. We could interpret games outside of the winning streak as evidence to whether he's a cheater or not. Instead, I believe they are looking at the question of "given this winning streak in particular, what's the probability of him cheating in this set of games"? They start with a prior (very low probability), I'm assuming they use the implied probabil…

> "given this winning streak in particular, what's the probability of him cheating in this set of games"

I think the problem lies in the antecedent. Given all chess tournaments played, how often would we observe such a winning streak on average? If the number of winning streaks is near the average, we have no indication of cheating. If it is considerably lower or higher, some people were cheating (when lower, than the opponents).

Then the question is, whether the numbers of winning streaks of one person are unusually high. If we would for example expect aprox. 10 winning streaks, but observe 100, we can conclude that aprox. 90 were cheating. The problem with this is that the more people cheat, the more likely we are to suspect an honest person of cheating as well.

Again, this would be different if the number of winning streaks for a particular person were unusually high.

Re: A recent chess controversy

#115

Post by lcnPylGDnU4H9OF »

cortesoft wrote: post #4

This is basically an article describing why you can’t just look at an event after it occurs, see that it has some extremely rare characteristics, and then determine it was unlikely to happen by chance. It is like asking someone to pick a random number between 1 and 1 million and then saying, “oh my god, it must not actually be random… the chances of choosing the exact number 729,619 is 1 in a million! That is too rar…

My favorite way to describe this is in the context of predictions. It's the difference between throwing a dart to hit a target and throwing a dart to paint a target around where it lands.

Re: A recent chess controversy

#116

Post by indigodaddy »

steppi wrote: post #108
indigodaddy wrote: post #91

Earlier quoted context omitted.

General statistical question. If we say extend the coin flip example distribution to say 10B times. Should/would we expect to see a streak of 100 or even 1000 in the distribution somewhere? Intuition alone tells me probably not for 1000 but a smallish chance for 100 (even if 10B in a row i would think a streak of 100 would be unlikely)

Your intuition's not bad. The expected value for the longest run of heads in N total flips of a fair coin is around log2(N) - 1 with a standard deviation that's approximately 1.873 plus a term that vanishes as N grows large. log2(10B) - 1 is approximately 32 and with that standard deviation, even a run of 100 in 10B flips is incredibly unlikely. For more info see Mark F. Schilling's paper, "The Longest Run of Heads"…

Neat! I guess this is a common thing to wonder about :)

Re: A recent chess controversy

#117

Post by permo-w »

alfiedotwtf wrote: post #111
permo-w wrote: post #62

Earlier quoted context omitted.

not really. this may be true for the average player, but as Magnus has explained multiple times, all he or another top GM would need to be near-unbeatable would be to check an engine in 1 or 2 critical positions per game. this essentially impossible to detect statistically. even if a cheater were to use an engine on every move, it would be trivial to just vary the engine used for each turn, vary the number of moves p…

What I don’t understand is that Hikaru can visualise in his head 30+ moves ahead from both plays, and yet he’s not better than Magnus?

??

I'm all for having a Hikaru/Magnus discussion--one of my favourite topics--but this just doesn't make sense

Re: A recent chess controversy

#118

Post by NedF »

cortesoft wrote: post #4

This is basically an article describing why you can’t just look at an event after it occurs, see that it has some extremely rare characteristics, and then determine it was unlikely to happen by chance. It is like asking someone to pick a random number between 1 and 1 million and then saying, “oh my god, it must not actually be random… the chances of choosing the exact number 729,619 is 1 in a million! That is too rar…

> This is basically an article describing

This is entirely wrong and missing basic high school mathematics for non-theater kids.

The original claim is not archived, if you can be bothered you can track it down and do the correct 'hot take'. You can't just grab the first statistical principal you think of even if everyone else on Hacker News does.

Article - "it violates the likelihood principle", this seems wrong and Nakamura seems right, but you'd have to look at the original claim.

They were finding patterns in a long biased list of numbers, probably.

Re: A recent chess controversy

#119

Post by zippyman55 »

michaelt wrote: post #29
giancarlostoro wrote: post #13

Earlier quoted context omitted.

I'm just trying to figure out how you even cheat on chess, the only thing that comes to mind is moving pieces, and sneaking new ones on the board, but if there's enough cameras, how do you get away with it, eventually someone WILL notice, highlight it, point it out, and you will be shamed.

> I'm just trying to figure out how you even cheat on chess, You use a chess engine to tell you the best move - you can run a chess engine on a modern phone that will easily best the world's top human chess players. The simplest forms of this are things like: "play online, chess engine open in another window", "use your phone hiding in a bathroom cubicle" and "member of the audience follows your game with a chess eng…

There is a Java script plugin for lichess that verbally tells you the best move in each position. I installed it (only for eval) and won my game (so unfair! But it was a random and not rated game). I removed the script. So it would be easy to use this or something like this to announce game changing situations.

Re: A recent chess controversy

#120

Post by zippyman55 »

gosub100 wrote: post #58
kevin_thibedeau wrote: post #38

Earlier quoted context omitted.

Future chess games will have to be played as Faraday cage matches. Two men enter, one man leaves.

This makes me want to cheat just as a technical challenge. Could I hide a computer in my hair? Could I ingest a capsule computer and communicate with it using the resonance of my teeth chattering? (No, I would not insert one in an inappropriate place). I'm sure it would be a downer that I cheated but it would do them a favor by saying: "look, you cannot stop it. Time for something new".

Hide a computer in your chess clock. A small camera would view the board and somehow flash a code on the lcd display of the clock.
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