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Ancient war trickery is alive in math today

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11–20 of 26 posts

Re: Ancient war trickery is alive in math today

#11
I've read about it many years ago, possibly in some book about cryptography, maybe. AFAIR it's used in some algos in this field.

But its application to counting troops... well, this sounds like a really overdone method of doing this. Maybe it has been tried once or twice, but I guess it's probably more of an urban legend, than something that could be pragmatically used on a daily basis.

Re: Ancient war trickery is alive in math today

#12
> the Chinese mathematician Sun Tzu (not to be confused with Sun Tzu who wrote The Art of War almost 1,000 years earlier).

Well, this is the kind of result you get if you insist on referring to people by the combination of a common last name and a standard courtesy title. Imagine if we referred to the author of The Wealth of Nations as "Mr. Smith" instead of "Adam Smith".

Re: Ancient war trickery is alive in math today

#13
post #4

> “If there are no solutions modulo a prime, then you know there are no solutions,” Can anyone point me towards a proof of this?

This quote is specifically about Diophantine equations.

You can find a similar statement as "Proposition 3.2.2" in Chapter 3 "Modular Arithmetic" [1] of this introductory course [2] to Number Theory. Here is a picture of the statement [3].

Basically, if there exists a number n such that there is no solution modulo n, then you know there are no solutions. Here is a simple application [4] of the proposition with n = 2 and 3.

[1] http://www2.math.ou.edu/~kmartin/intro-nt/ch3.pdf> [2] http://www2.math.ou.edu/~kmartin/intro-nt/>

[3] https://i.ibb.co/8mNHW0Q/2021-09-20-10-34-25.png> [4] https://i.ibb.co/Qffr9k2/2021-09-20-10-56-29.png>

Re: Ancient war trickery is alive in math today

#14
post #11

I've read about it many years ago, possibly in some book about cryptography, maybe. AFAIR it's used in some algos in this field. But its application to counting troops... well, this sounds like a really overdone method of doing this. Maybe it has been tried once or twice, but I guess it's probably more of an urban legend, than something that could be pragmatically used on a daily basis.

The legend could reasonably be true if you assume the generals just used the process for communication: "my troop strength is (3, 7, 2)." Actually lining up the troops seems unnecessary: it takes far less mathematical sophistication to calculate the moduli than to reverse engineer the total number.

Re: Ancient war trickery is alive in math today

#15

> the Chinese mathematician Sun Tzu (not to be confused with Sun Tzu who wrote The Art of War almost 1,000 years earlier). Well, this is the kind of result you get if you insist on referring to people by the combination of a common last name and a standard courtesy title. Imagine if we referred to the author of The Wealth of Nations as "Mr. Smith" instead of "Adam Smith".

Imagine referring to someone by common first name found by flicking through the first pages of the bible, and then a a reference to a vague class of ubiquitous professions.

https://en.m.wikipedia.org/wiki/Adam_Smith_(disambiguation)

They should all use use a unique hanzi name or an ORCID or a UUID or something.

Re: Ancient war trickery is alive in math today

#16

> the Chinese mathematician Sun Tzu (not to be confused with Sun Tzu who wrote The Art of War almost 1,000 years earlier). Well, this is the kind of result you get if you insist on referring to people by the combination of a common last name and a standard courtesy title. Imagine if we referred to the author of The Wealth of Nations as "Mr. Smith" instead of "Adam Smith".

Writing the tones could help a lot as it basically multiplies the number of possible names by 5 per character, so for 3 character names (which seem common in China) we get 125 fold increase in the possible names.

Re: Ancient war trickery is alive in math today

#18
We made good use of this technique when counting the number of legal Go positions [1].

"Clever use of the Chinese Remainder Theorem allows for splitting the computation into 9 independent parts, each computing L19 modulo 2^64 minus some small number, contributing 64 bits of the 566 bit result."

[1] https://tromp.github.io/go/legal.html

Re: Ancient war trickery is alive in math today

#19
post #16

> the Chinese mathematician Sun Tzu (not to be confused with Sun Tzu who wrote The Art of War almost 1,000 years earlier). Well, this is the kind of result you get if you insist on referring to people by the combination of a common last name and a standard courtesy title. Imagine if we referred to the author of The Wealth of Nations as "Mr. Smith" instead of "Adam Smith".

Writing the tones could help a lot as it basically multiplies the number of possible names by 5 per character, so for 3 character names (which seem common in China) we get 125 fold increase in the possible names.

It doesn't help here, the characters are 孫子 in both cases. Their names are just as identical as George Washington and Denzel Washington.

It's not going to help much in general, because Chinese family names just aren't that diverse.

Re: Ancient war trickery is alive in math today

#20
post #15

> the Chinese mathematician Sun Tzu (not to be confused with Sun Tzu who wrote The Art of War almost 1,000 years earlier). Well, this is the kind of result you get if you insist on referring to people by the combination of a common last name and a standard courtesy title. Imagine if we referred to the author of The Wealth of Nations as "Mr. Smith" instead of "Adam Smith".

Imagine referring to someone by common first name found by flicking through the first pages of the bible, and then a a reference to a vague class of ubiquitous professions. https://en.m.wikipedia.org/wiki/Adam_Smith_(disambiguation) They should all use use a unique hanzi name or an ORCID or a UUID or something.

There's a pretty large difference between referring to someone by a name held by less than 2% of the population vs a title extended to closer to 100% of the relevant population. Identifying people by full name is far, far more informative than identifying them by surname alone.
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