12,046 reputation
436108
bio website ncatlab.org/nlab/show/…
location Adelaide, Australia
age 31
visits member for 5 years, 8 months
seen 45 mins ago

Pure mathematician interested in category theory and foundations.


11h
awarded  Nice Answer
2d
comment Angle sum of triangle in Schwarzschild solution
At the very least this depends a priori on the mass of the star and the positions of the corners. Are you taking $A,B$ and $C$ as points on a spacelike slice, or just as points in the 4-dimensional manifold (i.e. 'events')?
Jul
28
comment Is there a generalization of homotopy groups to fractional dimensions
'the special values of some horribly incomputable arithmetic-p-adic-y-L-type function' -- nice :-)
Jul
28
comment Rearrangement of a spherical harmonics expansion
P Méléard, T Pott, H Bouvrais, JH Ipsen, Advantages of statistical analysis of giant vesicle flickering for bending elasticity measurements. The European physical journal. E, Soft matter 34 (2011) 116-129, citeseerx.ist.psu.edu/viewdoc/…
Jul
28
comment Rearrangement of a spherical harmonics expansion
How about giving an actual bibliographic reference, so that people can check the article themselves? No comment as to the appropriateness of MO for this question
Jul
28
comment Does every Lawvere theory arise in this way?
Since the Lawvere theory for a variety of algebras is given by the opposite of the category of finitely presented free algebras, shouldn't $X$ be the "free algebra on one generator" (whatever that is)?
Jul
28
comment Does every Lawvere theory arise in this way?
In that second example, did you mean "Lawvere theory of $\mathbb{K}$-modules"?
Jul
27
revised Smooth 4-manifolds with $E_8$ intersection form
Replaced journal link with DOI link.
Jul
25
comment A question about sentences undecidable in Peano's Arithmetic
OK, thanks. I was worried you had access to some higher truth somehow, rather than working in ZFC.
Jul
24
comment A question about sentences undecidable in Peano's Arithmetic
"...and it's not refutable because it's true." really? How does one get this?
Jul
23
comment Singularizing forcing of “small” cardinality?
This is a really nice result!
Jul
23
comment How can I solve a diophantine equation with 3 variables?
Allow me to correct my second sentence: you only have 5 or so values of $x$, given the constraint in my last sentence, and for each of those, you can divide by 17 and start again.
Jul
23
comment How can I solve a diophantine equation with 3 variables?
@Noam yes, I agree, but in this case it is something that a first-year programmer could do, even if not efficiently. If the question was about theoretical reasons or algorithms to attack the general problem efficiently...
Jul
23
comment Elementary Number Theory Text from a Categorical Perspective
The YouTube video in Edit 1 is no longer available.
Jul
23
comment Residue class sufficiency sets for the Collatz conjecture
I added the [reference-request] tag.
Jul
23
revised Residue class sufficiency sets for the Collatz conjecture
Added tag
Jul
23
comment How can I solve a diophantine equation with 3 variables?
Plug in some values of $x$ and get a two-variable equation. Given you've got 78 possible values of $x$ this is best done programmatically. This then is not really an MO-question, since it's more about implementation. Also, since $289=17^2$, $3367-x$ must be a multiple of 17.
Jul
23
revised Some references for f-ring
Spelling and grammar
Jul
20
comment Elementary treatment of elementary functions in constructive math
Is it possible to extract from proofs using calculus, say by Taylor's theorem, something that you are after?
Jul
19
comment Number of path components of a function space
If $Y$ is a sphere then this would be the cohomotopy $\pi^k(X)$. Surely one can then relate this to what you've got via $SU(2) \to U(2)\to U(1)$, since $SU(2)$ and $U(1)$ are spheres...