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Law of Similarity?

#1 User is offline   pljr 

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Posted 2020-November-26, 10:12

I recall an empirical "law" that said that if you had a long suit then maybe that was the same pattern in other hands.

I have looked for more info without success.

Any ideas please?

I believe it wasn,t true.
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#2 User is offline   hrothgar 

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Posted 2020-November-26, 10:58

This is a weird claim from 60+ years ago, back before computer dealt hands.

It has absolutely no validity (assuming fair shuffling)
Alderaan delenda est
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#3 User is offline   pilowsky 

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Posted 2020-November-26, 13:51

It's a great urban myth though.
I used to believe that if the cards were new then I was more likely to get a distributional hand. I got flamed for that thought.

Perhaps we should have a Bridge Urban Myths Section? (BUMS).


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#4 User is offline   pescetom 

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Posted 2020-November-26, 14:04

View Postpljr, on 2020-November-26, 10:12, said:

I recall an empirical "law" that said that if you had a long suit then maybe that was the same pattern in other hands.

I have looked for more info without success.

Any ideas please?

I believe it wasn,t true.


Most postulates proposed as "laws" are unreliable at best and this one (the "law of similarity") was clearly nonsense even in its time.
The originator was of course Ely Culbertson, somewhere between bridge genius and con-man.
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#5 User is offline   nige1 

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Posted 2020-November-26, 17:34

It was Culbertson's "Law" of Symmetry.
e.g. Singleton kings :)
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#6 User is offline   Cyberyeti 

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Posted 2020-November-26, 17:53

View Posthrothgar, on 2020-November-26, 10:58, said:

This is a weird claim from 60+ years ago, back before computer dealt hands.

It has absolutely no validity (assuming fair shuffling)


The fair shuffling comment matters, I recall a deal with new cards where all 4 hands were (6421) with identical pips within each suit.
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#7 User is online   thepossum 

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Posted 2020-November-26, 18:06

Suppose you have a 7-2-2-2 hand vs a 4-3-3-3 hand

Surely the distribution of the remaining cards is such to shift the chance of others having a long suit - who knows how much by - I doubt you could assume much about others having similar distributions, but come on it seems obviousl, albeit hard to calculate.

It was always a bit depressing when a night seemed to become defined by a boring pack of cards - time to try another one sometimes

But then again I imagine boring distributions are the bulk of the bridge deal space with occasional bright interesting patches - much like life, the universe and everything really :) In fact come to think of it, when I watched a video of John Conway discussing surreal numbers he seemed to have a similar philosophy towards infinity, that only a relatively small part of it was interesting - sorry for the paraphrase - apologies, it was more along the lines of levels or types of interestingness of different parts so he concentrated on the most interesting bit

There may be something useful in this page by Pavileck on Freakness

I heard once that if you had a 13-0-0-0 hand it was likely someone else had a void somewhere


Has anyone written anything interesting on shuffling theory :) Maybe an idea (not serious) for bridge software would be to have different shuffling algorithms to make it more interesting (has it been done)
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#8 User is offline   mikeh 

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Posted 2020-November-26, 23:11

View Postpljr, on 2020-November-26, 10:12, said:

I recall an empirical "law" that said that if you had a long suit then maybe that was the same pattern in other hands.

I have looked for more info without success.

Any ideas please?

I believe it wasn,t true.

You are correct


Culbertson, one of the pioneers of the game, believed in what he called the Law of Symmetry

I dont believe any good player believes in it these days.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari
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#9 User is offline   blackshoe 

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Posted 2020-November-27, 07:28

According to P.E.I. Bonewits, the Law of Similarity is one of the laws that govern the creation of magical spells. Bonewits was the only person who had a degree in Magic from a major Western university (B.A., U.C. Berkeley, ca. 1970). B-)
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#10 User is offline   pilowsky 

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Posted 2020-November-27, 13:57

Isn't everything the same?
non est deus ex machina; även maskiner behöver lite kärlek, J'ai toujours misé sur l'étrange gentillesse des robots.
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#11 User is offline   pescetom 

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Posted 2020-November-27, 14:20

View Postthepossum, on 2020-November-26, 18:06, said:

I heard once that if you had a 13-0-0-0 hand it was likely someone else had a void somewhere

As this hand has a generic frequency of 6 x 10 to the power of -10, it seems somewhat academic :)
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#12 User is offline   mycroft 

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Posted 2020-November-27, 16:24

Ah, it's more common than that - it's shown up in at least 4 books that I own.

Almost always when it's shown up, of course, it's because a new deck was put in a board by suits (or, back in the day, when we suited boards on last play to be able to create the hands from handouts) and not shuffled/made/dealt.
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#13 User is offline   pescetom 

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Posted 2020-November-27, 16:49

View Postmycroft, on 2020-November-27, 16:24, said:

Almost always when it's shown up, of course, it's because a new deck was put in a board by suits (or, back in the day, when we suited boards on last play to be able to create the hands from handouts) and not shuffled/made/dealt.

Back in the day? We still do that.
Indeed my alternative reply was that it was even likely that each other hand had 3 voids.
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#14 User is online   thepossum 

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Posted 2020-November-27, 20:00

View Postpescetom, on 2020-November-27, 14:20, said:

As this hand has a generic frequency of 6 x 10 to the power of -10, it seems somewhat academic :)


I know but some people may want a special convention to cover it

Would a transfer work

It would be sad to get excited and bid no trumps

I do imagine a lot of people would pass in case they were accused of psyching

But seriously getting back to the OP have there been attempts at analysing or proving such things. Could you not prove it on a simplified game
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#15 User is offline   HardVector 

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Posted 2020-November-28, 01:03

The "law" I had heard of postulated that hand patterns repeated in the suits. So if you have a 5332 hand, there will be a suit that is 5332. I heard of it about 30 years ago as hearsay and have never heard it again. It was in conjunction with the idea that if you have a void, there will be another hand with a void out there.
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#16 User is offline   pilowsky 

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Posted 2020-November-28, 01:32

View PostHardVector, on 2020-November-28, 01:03, said:

The "law" I had heard of postulated that hand patterns repeated in the suits. So if you have a 5332 hand, there will be a suit that is 5332. I heard of it about 30 years ago as hearsay and have never heard it again. It was in conjunction with the idea that if you have a void, there will be another hand with a void out there.


That law is completely true. But it is very difficult to prove.
There is one good scientific explanation though which was provided by another computer that you can see here.
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#17 User is online   thepossum 

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Posted 2020-November-28, 05:49

I reckon you could try something by induction

Consider a simple game. 2 players. 2 cards each, 2 suits etc
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#18 User is offline   hrothgar 

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Posted 2020-November-28, 07:09

View Postthepossum, on 2020-November-27, 20:00, said:


But seriously getting back to the OP have there been attempts at analysing or proving such things.


Yes

It is trivial to demonstrate that this is complete nonsense for either

A. Computer dealt hands or
B. Hands that a hand shuffled in "good" manner

It is possible that there is some truth for this for hands that are manually shuffled using some "poor" technique. The problem here is that almost any claim is consistent with bad shuffling.

The only way to really analyze this is to collect all sorts of data about hands that are manually shuffled in bridge clubs and use this to test the hypothesis. There was a data set that got posted a few months back from one bridge club in the Netherlands. As I recall, it didn't show anything particularly interesting.

Quote

Could you not prove it on a simplified game


The issue here is not the complexity of the game, but rather the availability of the data
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#19 User is offline   pescetom 

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Posted 2020-November-28, 09:52

View PostHardVector, on 2020-November-28, 01:03, said:

The "law" I had heard of postulated that hand patterns repeated in the suits. So if you have a 5332 hand, there will be a suit that is 5332. I heard of it about 30 years ago as hearsay and have never heard it again. It was in conjunction with the idea that if you have a void, there will be another hand with a void out there.


You are right. To quote from a 1933 newspaper article by Ely Culbertson:
"It was original with me, and I have long recommended it to all bridge players because I know how valuable it has been to me, and thus can be to them. The player must simply remember that whatever the pattern of any hand of 13 cards dealt, there will probably be a suit pattern which corresponds to it. Thus if a player's hand is divided five-four-three-two-one(sic), the distribution of some suit in the four hands will probably be five-four-three-one also. This varies, of course, but only to the extent of one card. That is, the equivalent suit may be divided five-four-two-two."

Almost one hand in four is either 5431 or 5422, so allow space for "exceptions" and this "law" might be seen to work.
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#20 User is online   thepossum 

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Posted 2020-November-28, 14:31

View Posthrothgar, on 2020-November-28, 07:09, said:

Yes

It is trivial to demonstrate that this is complete nonsense for either

A. Computer dealt hands or
B. Hands that a hand shuffled in "good" manner

It is possible that there is some truth for this for hands that are manually shuffled using some "poor" technique. The problem here is that almost any claim is consistent with bad shuffling.

The only way to really analyze this is to collect all sorts of data about hands that are manually shuffled in bridge clubs and use this to test the hypothesis. There was a data set that got posted a few months back from one bridge club in the Netherlands. As I recall, it didn't show anything particularly interesting.



The issue here is not the complexity of the game, but rather the availability of the data


Come on Richard, until now I gave you credit for a fair bit of understanding of maths and the concept of proof..it's nothing to do with shuffling at all. It's a mathematical proofs, whether possible analytically or not I don't know

Unless of course by shuffling we are discussing complete randomness with any hand equally likely etc

And in terms of data you would need however many times 10^28 hands and a large database. Sorry the number of hands has been reduced considerably by the OPs hand

But it's obviously and selfevidently true. But I don't know if it's provable


Just by way of an aside I read something about a law of similarity in Gestalt psychology. It seemed to me a statement of the obvious too
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