
Thinking outside the 10-dimensional box
About this video
3Blue1Brown visualizes high-dimensional spheres to explain a surprising puzzle about how a sphere fits in a box as dimensions grow. It builds geometric intuition for counterintuitive properties of high-dimensional space.
Why it appears in the archive
HN recommends it as the go-to intuitive visualization of high-dimensional geometry, relevant to machine learning, optimization and sphere packing.
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From the Hacker News discussion
A trick for visualizing higher dimensions: [VIDEO] Only 383k subscribers. Hmm. Remember to subscribe, comment, and smash that like button. Real Engineering is another great channel. And of course Veritasium and Numberphile.
Read original comment ↗Don't forget 3Blue1Brown's incredible video about visualizing higher dimensions[1]. He's getting to xkcd levels of "Of course there's a relevant video" [1]: [VIDEO]
Read original comment ↗There's a great 3blue1brown video that demonstrates this unintuitive result in a relatively intuitive way: [VIDEO]
Read original comment ↗Great article! I've been thinking about this on and off recently, as I wonder if we might be having intuitive issues when it comes to gradient descent optimization. 3 Blue,1 Brown had a video recently that kicked off my head scratching and is a great complement to your article: [VIDEO]
Read original comment ↗As you increase the dimensionality of a sphere, an ever-increasing proportion of the sphere is within epsilon of the surface. This 3Blue1Brown video addresses enough related stuff that the rest should become reasonably comprehensible: [VIDEO] This particular result is tossed in as a side note around 23:25, so it's not addressed directly, but it'll help.
Read original comment ↗Three Blue, One Brown has a decent video which perhaps helps get a handle on how one can use higher-dimensional spaces, without needing to wrap you head around trying to envision a four-dimensional cube, or similar. [VIDEO]
Read original comment ↗I would reiterate that simply because there are problems with naive visualization, we shouldn't discredit visual thinking. There are several key elements to effective visual thinking. The primary importance is to keep it grounded in proofs and theorems, so you know exactly what are your limitations. Often you can use a geometric argument on top of a few theorems and you get a very strong result intuitively, and then use this intuition with a tiny amount of algebra to prove it (which might take you forever to arrive from a purely algebraic perspective). Another key is that there are several ways of visualizing things. You can almost always transform a problem into an equivalent one that is easy to visualize (just need a little bit of care with the transformation, etc). --- For example, you can show functions form a vector space, visualizing some interesting algebraic properties about them, even if it constitutes an infinite-dimensional space. You can show several operators (such as d/dx) are linear, you can give it a norm, internal product, etc. This trick lets you use visual tools (and linear algebra tools) with arbitrary functions. You can visualize projection of a function into a subspace, or into some non-canonical basis -- yielding useful applications -- such as Fourier analysis. Fourier analysis itself is a fertile ground for visual thinking. You'll be finding trivial arguments for seemingly difficult decisions such as "Does this linear system have a bounded output for a
Read original comment ↗Yeah, I see now. “times i” is discrete 90 degree rotation itself, not just ‘i’, nor ‘b’. Thanks everyone for making that clear. This though shows that explanations via analogies or non-strict wording may confuse one rather than enlighten. I’m not good at math, but once understood to not search analogies or geometry in things. Instead it is better to “shut up and calculate”. Not sure if imagining something is required to manage it. It’s only our brain’s faulty quirk. [VIDEO]
Read original comment ↗