I thought there were several examples of theorems that had only been proved by computers, like the Four Color Theorem
Yes, although as far as I know things like that, and the FCT in particular, have only been proved by custom software written for the problem.
There’s also a distinction between using a computer to find a proof, and using it to formalise a proof found by other means.
Indeed, the computer-generated proofs of 4CT were not only not formal proofs, they were not correct. Once a decade, someone would point out an error in the previous version and code his own. But now there is a version for an off the shelf verifier.
Yes, although as far as I know things like that, and the FCT in particular, have only been proved by custom software written for the problem.
There’s also a distinction between using a computer to find a proof, and using it to formalise a proof found by other means.
Indeed, the computer-generated proofs of 4CT were not only not formal proofs, they were not correct. Once a decade, someone would point out an error in the previous version and code his own. But now there is a version for an off the shelf verifier.