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seen Nov 21 at 23:04

I was a graduate student in the Logic program at Berkeley, broadly interested in categorical logic and foundations of mathematics, as well as in applications of category theory to the semantics of programming languages. I work for Google now.


Nov
13
awarded  Autobiographer
Aug
6
comment ind-completion and functors which are full with respect to isomorphisms
"My interpretation is that you are looking for a condition that says that there are no more L-isomorphisms between direct limits of K-structures than what you would get by taking formal direct limits.". Is this not the question of whether the canonical map from ind-$C_K$ into $C_L$ is iso-full?
May
12
revised Commuting limits in relating the harmonic series to coprimality densities
edited body
May
11
asked Commuting limits in relating the harmonic series to coprimality densities
Feb
25
comment Product of all elements in an odd finite abelian group is 1
This is essentially the classical proof of the general Lagrange's theorem (rather than the alternative proof, already invoked, which establishes Lagrange's theorem only for cyclic subgroups of a finite abelian group), specialized to this case. You are divvying G into its orbits under the action of the subgroup generated by j, noting that these orbits all have cardinality equal to the order of (the subgroup generated by) j, and thus concluding that the order of j divides the order of G.
Jan
12
awarded  Yearling
Aug
31
awarded  Scholar
Aug
31
accepted Derivatives as defined by a two variable difference quotient limit
Aug
30
comment Calculate $\pi$ to an accuracy of 5 decimal places?
What do you mean when you say "I know... how to choose how 'far' I should calculate"? Because that's precisely the question you are asking.
Aug
30
revised Derivatives as defined by a two variable difference quotient limit
added 10 characters in body
Aug
30
asked Derivatives as defined by a two variable difference quotient limit
Aug
30
comment Why use the derivative and not the symmetric derivative?
What happens if we remove the restriction that r > 0 and s > 0 (and just ask that they not sum to zero)? What extra properties must a function differentiable at x satisfy for the two-variable difference quotient limit (in r and s) to exist? [E.g., I believe it suffices for the function to be continuously differentiable. How tight a restriction is this?]
Jan
14
revised Gödel's incompleteness theorem can't be proven?
added 62 characters in body
Jan
14
comment Gödel's incompleteness theorem can't be proven?
In computational terms, Goedel's result is the undecidability of the halting problem, as you note, while Rosser's result is the uncomputability of every total function extending the partial function which sends programs to their outputs.
Jan
13
awarded  Supporter
Jan
13
comment Comparison of simple axioms with the Lebesgue integral
Indeed, I found that interesting reading; thank you for the link! It now seems to me that the axioms I've given are equivalent to the Daniell integral, which answers all my questions. (Unless there is something subtle but significant I have missed?).
Jan
13
awarded  Nice Answer
Jan
13
revised Gödel's incompleteness theorem can't be proven?
added 16 characters in body
Jan
12
revised Gödel's incompleteness theorem can't be proven?
Minor correction to date; added 28 characters in body
Jan
12
comment Gödel's incompleteness theorem can't be proven?
Whoops, sorry; I meant to account for that! Thanks for catching that; I've fixed it now.