Summer of Math Exposition

Presented by 3Blue1Brown 3blue1brown

How a Prime Number problem leads us to Complex Analysis.

Audience:

Tags: number-theorycomplex-numberscyclotomic-polynomials

A video aimed at high-schoolers and undergrads motivating the study of Cyclotomic Polynomials with a simply stated problem in number theory.


Analytics

5.18 Overall score*
108 Rank
11 Votes
7 Comments

Comments

4.7

Although the visuals and explanations are logical and easy to follow, the subject matter doesn’t feel very well motivated - maybe a discussion about the problem’s place in number theory as a whole in the intro or conclusion could help. The use of complex analysis feels like an arbitrary tool rather than something motivated by intuition.

5

The content is okay, if a bit rushed/confusing without pausing and going back. The voice was also too quiet to accurately hear sometimes.

6.5

Nice video! I liked the introduction of the problem and the motivation for its generalisation and how this tied into some wider ranging ideas. I also really appreciate the pacing of sometimes not talking and simply letting things play out. My one tip would be to keep things on screen for longer, most notably the ‘chapter’ intros. Turning the divisor into the polynomial evaluation at 8:45 was very slick but might be misleading. It also felt a bit dense during the middle section, maybe there are ways to explain some of those calculations without doing them as explicitly?

4

Very math heavy with very little motivation behind it. It would be good as an exercise to work through, but without outside motivation, I would be hard pressed to try and understand this video.

5.3

This is an interesting problem, and I think that this problem-solving method really does exemplify the notion that “the complex numbers are unreasonably good at solving number theory problems.” That said, I have some issues:

  • …high school? I don’t want to get on your case about it because it doesn’t really affect the text of the video, but you realize that even just to get started with Euler’s identity, if anyone questions that the best reason why involves a concept from the end of most freshman calculus classes, which already eliminates the vast majority of high schoolers, right? Just because there are high schoolers at this level doesn’t actually mean it is “high school level”: honestly the confluence of the complex plane and number theory ideas makes it pretty tough for a lot of people at an undergraduate level.
  • The video is very dense, and I did have to pause numerous times to make sure I was keeping up with why any individual thing absolutely had to be true: I think that might mean you’re going a touch fast, maybe taking a little bit too much for granted in terms of what’s “clear” or “obvious.”
  • I personally find the topic sort of self-evidently interesting, and I suspect you do too, but I don’t think the same is necessarily true for your entire audience. Making it clear that introducing complex numbers to number theory is a broader problem-solving idea might be something that would make the content here feel less narrow for people who aren’t already aware of that.
  • I think the audio editing here is a bit distracting, the variance in fidelity isn’t ideal but the difference in volume leads to a slightly more strenuous listening experience than I think it should be, and I think this can actually affect how easy it is to take in the content.

Now that said, I still think the video overall is quality, because it does show this really neat idea in this problem people might not know otherwise. I just think it could do with some further refinement. Keep it up!

4

Some animations, especially in the first couple of minutes, moved very quickly without pauses and room to breathe. The constant changing without keeping the original made it hard to pause and understand.

I think a better “hook” would have been starting off directly by talking about bits and base-b digits. This might have helped sell this as something to care about. I would have also liked to see some discussion about why to care about the various generalizations.

6

The video showcases an interesting connection between number theory and complex functions, I think students would find it satisfying, but a bit too fast paced and requires pausing to truly grasp what’s going on. one of the best explanations for cyclotomic polynomials I have ever seen.