If you’re asking about math talent as in child prodigies, then one can browse previous winners of the math Olympiad. But I have a feeling his success as a prof

If you’re asking about math talent as in child prodigies, then one can browse previous winners of the math Olympiad. But I have a feeling his success as a professional mathematician involves the interaction of such math talent with hard work and good mathematical taste. One can read his PhD qualifying exams to observe he was actually not an outlier amongst his peers in his early career.