Not really, as a former theoretical physicist who also got offers from many math PhD programs and have many math PhD friends, by far the most recruiting emails we get are from quant trading firms, and you won’t find that kind of math on Math.SE.
But yeah, roughly speaking you need to at least be a math PhD student who have passed your quals to be at the entry level of MathOverflow.
But yeah, roughly speaking you need to at least be a math PhD student who have passed your quals to be at the entry level of MathOverflow.