Horobi no Kuni no Seifukusha - Vol. 1 Ch. 3 - A Distant War

[hermitowl]

That's the main thing about this story,

Spoiler: Plotline so far

it's an mc that's living in a kingdom that's on its last leg, and he has no particular superpower other than his knowledge of modern earth.
Paired with a nationalist princess As a girlfriend, he tries to find any way to be safe with the people he loves.

That's cool too.

A good general prepares for war.
A great general prepares to avoid war.

 

[Sp12er]

That's cool too.

A good general prepares for war.
A great general prepares to avoid war.

It's good enough I feel like it'd be a good VN plot, where there's tons of choices that end in a bad end with a couple good and true ending. The scope is big enough we can have a Mushoku Tensei style of story telling with the story spanning over Yuuri's aging to 30+.
Right now, Im hoping it's so as the problem he's facing really is something that can't be solved in 1 lifetime.

 

[Smokeball]

Japanese seems to be fine marrying the first cousin idea huh? I've seen a lot of people saying that it must be at least second counsin to be able to get married. In my country, even third and fourth cousin are still considered as relative and therefore cannot get married.

 

[rmremail]

Young nerds in love

 

[noname120]

guy really memorized all that eh

 

[DanYHKim]

Hahaha.
Lion throws cub off a cliff

 

[SirWrinkle]

just a nerd passing by.
so what are they discussing on page 27-29 is basically something called "Euclid's theorem of infinity prime numbers"

so Saim is wondering if prime numbers would keep going because the way she saw it, the gap between prime number are keep getting wider and wider the further the number goes. and why the fuck a 5 years old girl would even pondering about such a thing? it's just a phase.

so the MC is basically explaining it like.

2x3x5+1=31
2x3x5x31+1=931

the formula is basically that you're multiplying any prime number that you know, and then add 1 to the sum of it. using this formula would resulting in either P or Q
P is basically means: if you get a prime number as the end result. then that means you're multiplying ALL of the prime number in the correct order, since 31 is a prime number that means you got all of the first 3 prime number correct in equation

Q is basically means: if the end number wasn't a prime, that means the divisible of the sum would show you the prime number that you missed. 931 isn't a prime number since it's divisible by 7, 19, 49, & 133. which 2 of them are prime number which wasn't part of the equation.

this formula weren't meant to solve anything, but by the construct of it this formula prove that you could ALWAYS find a new prime number as long as you multiply all of them and add it by 1. thus why it's called theorem of infinity prime number.

you can google it if you want a further explanation, but this is basically the gist of it.

was on plane and got jet lag, decided to read this to spend some times... boy i couldnt even understand the first time i read it

 

[Wataterp]

Isn't she his cousin?

 

[Tanmoy1945]

Gotta learn some maths to flex in isekai after my passing.

 

[Tanmoy1945]

Isn't she his cousin?

Cousin marriages were very common in that era around the world.

 

[zigzag35]

Another nerd passing by~
Doesn't quite feel like that is what he is describing though.
Take a look at what he said:

• Let 'N' be a number equal or greater than 2
  • N and N+1 can't share any divisor > 1
• N*(N+1) = X
• M = "number of prime numbers" = infinity
• get_factors(M).filter(n=>is_prime(p)).length >= 2
  • -- unsure what get_factors is menat to do, but most likely it returns the list of prime-factors... except his added clause about counting the number of factors that are primes, as opposed to simply using the size directly, implies it isn't what he meant So maybe he means the list of all possible factors that could be used when factorizing? Like how "8" can be both "2x2x2" and "2x4" and "2x8", so get_factors(8) == [1,2,4]?
  • in other words, he states that the number of prime-factors in "infinity" is >= 2.
    • -- I'm sorry, what?
• assert( get_factors(M).filter(is_prime).length != get_factors(M).filter(is_prime).length )
  • -- I'm sorry, what?
• typeof(M*(M+1)) is Array && (M*(M+1)).filter(is_prime).length >= 3
  • or if we substitute M: typeof(infinity*(infinity+1)) is Array && (infinity*(infinity+1)).filter(is_prime).length >= 3
    • -- I'm sorry what?

The first and biggest issue is clearly when he defines M as infinity ("number of primes").
If we look at euclids theorem instead, we get this:

• Have an arbitrary (finite) list of primes defined through an arbitrary number "P" (which is the result from multiplying all primes in the list - aka the list of primes is "get_prime_factors(P)")
• Define q = P+1
  • if q is a prime: We prove that there is an additional prime outside of the initial set.
  • if q is not a prime: get_prime_factors(q) contains some prime-factor "p".
    • If this p were in our initial set: it would be able to divide both P and P+1, meaning p can also divide the difference "1" (which it can't). So this case is impossible.
    • But if p were not in the initial set ("assert(get_prime_factors(P).has(p))"): we have shown existence of a prime outside the initial set
• Since both cases proves the existence of a prime outside initial set, if we then repeat this algorithm ad-infinitum (adding p to the set each time: "P = P*p; Jump 0;"), we will infinitely prove the existence of new primes. Q.E.D

That's a very different proof, and clearly not what mc did.


All the above jokes aside though, I think it is fairly safe to say that either mangaka or tl did not understand the math, and they were in fact trying to put something like euclids theorem to paper.

From years the future thank you for writing this. Reading that part had me thinking I can't let this disrespect slide lol. Glad someone did it while the ch was recent enough to get the word out there!!

 

[AMicrowave]

translating Gouki as Gowk was a bold choice