this post was submitted on 26 Jun 2025
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There have been a number of Scientific discoveries that seemed to be purely scientific curiosities that later turned out to be incredibly useful. Hertz famously commented about the discovery of radio waves: “I do not think that the wireless waves I have discovered will have any practical application.”

Are there examples like this in math as well? What is the most interesting "pure math" discovery that proved to be useful in solving a real-world problem?

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[–] JackbyDev@programming.dev 39 points 6 days ago (6 children)

It's imaginary numbers. Full stop. No debate about it. The idea of them is so wild that they were literally named imaginary numbers to demonstrate how silly they were, and yet they can be used to describe real things in nature.

[–] alt_xa_23@lemmy.world 16 points 6 days ago (5 children)

I'm studying EE in university, and have been surprised by just how much imaginary numbers are used

[–] underscores@lemmy.zip 8 points 6 days ago* (last edited 6 days ago)

EE is absolutely fascinating for applications of calculus in general.

I didn't give a shit about calculus and then EE just kept blowing my mind.

[–] pineapplelover@lemm.ee 5 points 6 days ago

I was gonna ask how imaginary numbers are often used but then you reminded me of EE applications and that's totally true.

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[–] CanadaPlus@lemmy.sdf.org 5 points 6 days ago* (last edited 6 days ago) (5 children)

I mean, quaternions are the weirder version of complex numbers, and they're used for calculating 3D rotations in a lot of production code.

There's also the octonions and (much inferior) Clifford algebras beyond that, but I don't know about applications.

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[–] amelia@feddit.org 21 points 6 days ago (1 children)

As far as I know, matrices were a "pure math" thing when they were first discovered and seemed pretty useless. Then physicists discovered them and used them for all sorts of shit and now they're one of the most important tools in in science, engineering and programming.

[–] Buddahriffic@lemmy.world 4 points 6 days ago

Huge in 3d graphics and AI.

[–] Etterra@discuss.online 23 points 6 days ago (1 children)

The invention of the number 0, the discovery of irrational numbers, or l the realization that base 60 math makes sense for anything round, including timekeeping.

[–] chonglibloodsport@lemmy.world 13 points 6 days ago (2 children)

60 was chosen by the Ancient Sumerians specifically because of its divisibility by 2, 3, 4, and 5. Today, 60 is considered a superior highly composite number but that bit of theory wouldn’t have been as important to the Sumerians and Babylonians as the simple ability to divide 60 by many commonly used factors (2, 3, 4, 5, 6, 10, 12, 15) without any remainders or fractions to worry about.

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[–] anachrohack@lemmy.world 2 points 4 days ago

Riemann went nuts working on higher dimensional mathematics and linear algebra. At the time there was not a clear use case for math higher than like 3 or 4 dimensions, but he drove himself crazy discovering it anyways. Today, this kind of math underlies all of artificial intelligence

[–] Feathercrown@lemmy.world 8 points 6 days ago

Imaginary numbers probably, they're useful for a lot of stuff in math and even physics (I've heard turbulent flow calculations can use them?) but they seem useless at first

[–] CanadaPlus@lemmy.sdf.org 5 points 6 days ago* (last edited 6 days ago)

Strangest? Functional analysis, maybe. I understand it's used pretty extensively in quantum field theory, although I don't actually know firsthand.

That's a body of mathematics about infinite-dimensional spaces and the operations on them. Even more abstract ways of defining those operations exist and have come up as well, like in Tseirlson's problem, which recently-ish had a shock negative resolution stemming from quantum information theory.

There's constructions I find weirder yet, but I don't think p-adic numbers, for example, have any direct application at this point.

[–] ikidd@lemmy.world 5 points 6 days ago (1 children)
[–] ceramicsky@lemmy.world 3 points 6 days ago

Integration was literally developed to be useful

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