bio  website  ncatlab.org/nlab/show/… 

location  Adelaide, Australia  
age  31  
visits  member for  5 years, 6 months 
seen  7 hours ago  
stats  profile views  10,416 
Pure mathematician interested in category theory and foundations.
2d

comment 
Differential Topology over $\mathbb{Q}$
@SimonHenry  really? The disjoint union of uncountablymany copies of $\mathbb{R}$ is paracompact is it not? Or are you assuming second countability in your definition of 'ordinary manifold'? 
May 21 
comment 
Can a cylinder be regarded as a Riemannian manifold?
You could consider it as a CAT(n) space, perhaps... 
May 21 
comment 
Alternating Reciprocal of Squares
The sum expression was wrong, so I corrected it. The alternating series converges, since the series converges absolutely. Not sure if this question will be well received. 
May 21 
revised 
Alternating Reciprocal of Squares
Corrected sum expression 
May 21 
comment 
try to calculate the probability
This question is offtopic. MO is (to a first approximation) for questions for professional researchers in mathematics. 
May 21 
comment 
A model category of abelian categories?
@TheoJohnsonFreyd The paper is at arxiv.org/abs/1402.7108 
May 20 
comment 
What's so great about blackboards?
The thing that any slide presentation, with current technology lacks, is real estate. Unless one is stuck with a tiny board the size of a projector screen, you have so much more to play with (six boards! eight boards!! Imagine having that many simultaneous projected slides) 
May 19 
comment 
Suggest a reading list to start TQFT
I suggest this question might be suited to math.stackexchange. More detail about your background might help, since 'a graduate degree in physics' contains different levels of maths depending where you are. 
May 18 
comment 
Intrinsic definition of arc length
@Joonas by 'trace' do you mean the image of a defining function? Assuming a finite set of selfintersection points should sort that out (or perhaps measure zero!) 
May 18 
comment 
I have to show any noninvertible matrix is a reducible matrix
Why do you have to show it? 
May 18 
comment 
Intrinsic definition of arc length
@Cusp probably not. Such an approximation only requires a bunch of points on the curve, and one can define the error of the approximation via the sum of the maximum and the minimum of the length of the line segments in the approximation. Presumably for rectifiable curves as this 'error' approaches zero the usual distance (L^1 metric, say) approaches zero. 
May 18 
answered  Old books still used 
May 18 
comment 
Mathematical research papers in general science journals
@Gerry well I never. +1 for you! It does sit under the heading 'Physical sciences'  a slight lie  but with subheading 'Mathematics'. I note with interest that a mere three more mathematics papers have been published since I wrote this answer. Not exactly a flood... 
May 16 
comment 
Vandermond Invers using Lagrange
This is offtopic. Do you want a Matlabspecific forum instead? Or otherwise there are other stackexchange sites that may help. 
May 15 
comment 
explicit integrals over a Lie group
And for some other functions mathoverflow.net/questions/36025/… 
May 15 
comment 
explicit integrals over a Lie group
Examples involving f=1: mathoverflow.net/questions/84848/… mathoverflow.net/questions/203836/volumeoftheunitarygroup 
May 15 
comment 
How to learn QFT from mathematical perspective?
Note that we don't actually understand QFT mathematically! (In general). There are bits and pieces we know, but it's like knowing calculus in the 18th century: hacks, tricks and a few good examples, but no overarching rigorous mathematical framework. 
May 14 
revised 
Henstock, Differentiation under the integral sign
added 434 characters in body; edited tags 
May 12 
revised 
About the trace class operators and their motivation
added 57 characters in body 
May 12 
comment 
A model category of abelian categories?
@TheoJohnsonFreyd well, let me finish editing it first :) It will most definitely be on the arXiv before the publisher gets their hands on it. 