When tackling IMO problems, the hard part is coming up with a good approach to the proof. Verifying your proof (and rejecting your false attempts) is much easier. You'll know which one to submit.
You are a human, not an AI. You know whether your idea seems related to the solution. The AI has thousands of ideas and doesn't know which are better. Graders shouldn't accept a thousand guesses grubbing for 1 point.
If verifying a good idea is easy, then the evidence shows that the AI didn't have good ideas for the other 2 problems.
we are talking about lean proofs. Given a formal statement and a proof - the lean can verify whether it's correct or not. It's like generating computer programs to solve a problem - the problem lied in generating useful solutions/sub-solutions so that the search is effective. They achieve this via using gemini as a lean proof generator aka. using a world model LLM fine tuned to generate lean proofs in a more effective manner.
Humans are even better at this as you mention - but effectively the approach is similar. Come up with lot of ideas and see what proves it.
Well, he does have twice the amount of silver medals... And can speak the English language... Although, an AI attempting to speak with the human race entirely through an esoteric math-proofing language would be an interesting take on the whole, "humans make ET contact, interact through universal language.... pause for half of the movie, military hothead wanting to blow it out of the sky, until pretty lady mathematician runs into the oval office waving a sheet of paper... OF MATH!" trope....
But now, it's a race between you and I, to see who can write the screenplay first!
(Source: I am a two-time IMO silver medalist.)