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Comment by bambax | Hacker News Reader

In Cube (1997) the characters are trapped in a labyrinth of sorts made of boxes (cubes) that they can escape by solving math riddles.

They're all supposed to be math geniuses, but very early on in the movie they take forever to decide if 645 or 372 are prime numbers... It kind of killed the suspension of disbelief for me right there...

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The authors probably didn't meant it, but this is surprisingly realistic of math geniuses (see stories of Grothendieck Prime and Weyl in the following thread)

https://hsm.stackexchange.com/questions/6358/story-of-grothe...

Yeah, finding out if a number is prime or not can be unintuitive. But I doubt Grothendieck would have had trouble with anything divisible by 2 or 5...

My math is rusty enough to find it helpful to explicate that 2*5 is the complete factorization to primes of 10, and our customary arithmetic base for numbers written on the page is likewise 10.

I like the Einstein quote about the speed of light - some smartass asked him to recite it, and he’s basically like “I don’t memorize trivial information that’s easily looked up in books”

Could be totally apocryphal, but I like the sentiment.

>“I don’t memorize trivial information that’s easily looked up in books”

holy X

I get accused at having a poor memory A LOT!.

And I constantly tell people, I have a great memory - there are just things I dont choose to commit to memory.

I can tell you every single password I have typed into a machine. FblQ00Ho <--- ix.netcom.com 1996

But I cant tell you WHAT YOU TOLD ME you ate for lunch yesterday and suddenly I am a jerk.

"Why cant you recall what I told you yesterday??!?!?!?"

UH, because thats ephemeral information I dont need to hold in my head?

Were they all supposed to be math geniuses? It's been a long time since I watched it but I recall just one math genius then a doctor, a police officer, an architect, a convict, and an autistic savant (who may have also been a math genius but was non-verbal?). I don't remember it being implied that the other characters were particularly mathematical.

except for the autistic crazy who just somehow knows

but I haven't seen that movie in many years, so I don't remember what he knows

but the actual test was 9 digits? (if i recall well)

I 'memorized' the first 31 primes! why? I'm not sure; but I know how I did it, I don't know what it means tho

I think you are missing the point here. The only even prime is 2. The only prime ending with a 5 is 5.

The last digit of a prime bigger than 5 can only be 1, 3, 7 and 9.

I'm looking for some point?

also, you're focused on base 10. And that 1,3,7,9 is the basis of the how i remember them: 11,13,17,19 then 23 AND ALSO 101,103,107,109, and then 113. but why!?

I learned that all twin primes in base 4 either end in 1 xor 3. and I know that all primes congruent to 1 modulo 4 can factorized into a complex number with its conjugate (Gaussian primes). But I don't understand this, I only 'know it'

And then, I figured that all the twin primes in base 6 are always end in 5 then in 1. and that's it, this is supposed to be a question by the way

I recommend re-reading the OC and the replies.

what is the OC? whose replies??

I think I gotta somehow get a better understanding of Mersenne and Eisenstein primes, but I don't like jumping through 'bureaucratic'-academic hoops to get things explained to me. it's only numbers, I have other things to do

If number end in 2 or 5, is divisible by 2 or 5. So number ending in 2 or 5 cannot be prime. Math no hard to understand!

but this is only because 10 in ten in decimal system

but the numbers are not (only) how they're written down!

meh...

Everything you've written is gibberish in spanish, why did you do that?

cuz it happens to be the first spoken language I learned?

does this answer your question? if not, maybe this can help: https://www.youtube.com/watch?v=BdOtR2A5agc

What the original commenter dislikes is that a bunch of "brilliant" mathmaticians can't instantly recognize that any number ending with 2 or 5(except 2 and 5) can't be a prime.

I.e

999999999999995%5=0 999999999999992%2=0

Thus they are not prime numbers.

I am not a mathematician or an actor, but if I played one in Hollywood movies I could certainly answer your questions, confidently and wrong. Interesting tangent, just off-topic.

https://mathworld.wolfram.com/GaussianPrime.html

Not a down-voter of this, but author is missing the understanding that the set of primes is intrinsic to the integers and the definition of multiplication, and in not in any way dependent upon how integers are written on the page (or in the memory of a computer).

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