Are there historical examples of conjectures widely believed to be true and then proven to be false?
I suppose Gödel's incompleteness theorems and Hilbert's second problem is along those lines, but I'm not sure Hilbert's problem was regarded as a conjecture.
I suppose Gödel's incompleteness theorems and Hilbert's second problem is along those lines, but I'm not sure Hilbert's problem was regarded as a conjecture.