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?
How do you define “pure math discovery”?
A math discovery unmotivated by research in other fields; just discovering math to see if it works out
With that as the definition I would say Boolean Algebra.