When a mathematician like Terence Tao says "I'm not good in Algebra" what does he actually mean?
Does that imply he's actually good at undergraduate level Algebra and perhaps even at masters level, but he "thinks" he would struggle (much more than others) with any real research in the field?
Or do they mean something completely different?
I'm really just curious about how good/bad these guys are in fields outside of their research area - which would indeed help explore a more fundamental question, which is perhaps too vague for the purpose of this website.