A nice example is that Gauss realized in 1805 that Fourier transforms could be made less tedious by subdividing the problem (n=12=3*4 in his case), 160 years before Cooley-Tukey.
> Bolyai’s son János was also a mathematician. In 1832, János published his brilliant discovery of non-Euclidean geometry. His father, overjoyed that his son might have achieved something worthy of praise from Gauss, the man he admired more than any other, asked Gauss for his view of the work.
There was a bit of a feud and I don't know if it was ever properly settled
> Whether Gauss actually fleshed-out non-Euclidean geometry as comprehensively as Bolyai and Lobachevsky is uncertain.
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https://www.famousscientists.org/gauss-and-non-euclidean-geo...