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After doing nearly all the coursework for a Ph.D. in math, I then did all the coursework for a Ph.D. in statistics and completed that degree.

1d
revised Probabilistic statement on matrix ranks
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1d
revised Philosophy behind Yitang Zhang's work on the Twin Primes Conjecture
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Jan
14
awarded  Popular Question
Dec
11
revised A sum-of-determinants identity
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Dec
10
comment A sum-of-determinants identity
I should have torn my brain away from the geometry question I was thinking about and thought: obviously this is algebra. Wondering about the geometric meaning in higher dimensions, of the choice of $\pm$ in each term was actually the main thing on my mind, and I haven't really done much with that yet. In dimension $2$ there are cases where one obviously wants to subtract, rather than add, the area of a triangle, and that's taken care of by the fact that the determinant is negative in those cases.
Dec
10
comment A sum-of-determinants identity
$\ldots$ and lots of trivially-provable-even-if-nontrivially-consequential identities are named after someone who lived usually before 1800 (but I think maybe determinants were not widely known until some time after that?) so we still have the question of whether this might be one of those, or whether it is only "trivially consequential" and so not worth doing that for.
Dec
10
comment A sum-of-determinants identity
$\ldots$ which just goes to show that algebra is efficacious; I should have shifted mental gears and thought of using it $\ldots$
Dec
10
comment A sum-of-determinants identity
@RichardStanley : Could be --- I was thinking about geometry, not algebra.
Dec
10
revised A sum-of-determinants identity
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Dec
10
asked A sum-of-determinants identity
Nov
10
awarded  Popular Question
Nov
10
revised Arctangents and the golden ratio
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Sep
30
comment Do these properties characterize differentiation?
I wonder what nice sets of conditions that include shift-equivariance are satisfied only by differentiation?
Sep
30
awarded  Explainer
Sep
24
awarded  Autobiographer
Jul
20
comment When is the earliest large prime gap also the latest large prime gap?
What do you mean by saying that the lim sup of the relative size is decreasing? The relative size is $(p_{n+1}-p_n)/p_n$. That is a sequence, and it has a lim sup, and its lim sup is a number, not a sequence. What would it mean to say a number is decreasing? (And I'll be very surprised if you tell me the lim sup is not $0$.)
Jul
20
revised Positively invariant set
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Jul
20
comment When is the earliest large prime gap also the latest large prime gap?
I notice that mathoverflow has no "prime gaps" tag. Stackexchange has that. Should that be created?
Jul
20
revised When is the earliest large prime gap also the latest large prime gap?
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Jul
20
comment When is the earliest large prime gap also the latest large prime gap?
@TheMaskedAvenger : I'm not seeing that your comment actually answers the questions. If I'm not mistaken, in the case of $113$, where the relative gap size, $(127-113)/113=14/113\approx 0.12389\ldots$ is bigger than any that occurs later. I have to suspect that "bigger than average" means bigger than some "average" that decreases as $n$ grows.