23,255 reputation
151133
bio website rybu.org
location Victoria, BC
age 40
visits member for 4 years, 10 months
seen 6 hours ago
I'm a professor of mathematics at the University of Victoria, in BC Canada.

16h
reviewed Close Multiplicative gradient descent?
16h
reviewed Close On the Picard group of a product of projective varieties
16h
reviewed Close extension of semilinear functional
16h
reviewed Close Relation between $\text{Hom}_{\mathsf{Alg}_{\mathbb{R}}}(\mathcal{C}^\infty(M),A) $ and $ X \otimes_\mathbb{R} A$?
18h
comment Does this integral have a closed form?
It looks like the question is receiving plenty of attention at the MSE site. I'm voting to close as this thread seems redundant. If MSE wants to migrate the question here, they can do that but there's no point having a duplicate here.
Sep
12
awarded  Nice Answer
Sep
11
comment Reference on representations of knot groups
But what kind of things do you want to know about these representations?
Sep
11
comment Reference on representations of knot groups
It would be difficult for a textbook to cover it entirely, as the subject is a little too thick for a not-too-huge textbook. Is there something in particular you would like to learn?
Sep
8
comment Objects which can't be defined without making choices but which end up independent of the choice
You can make a choiceless definition of trace by defining it to be the infinitesimal rate of change of volume distortion, as one perturbs the identity automorphism in the direction of the matrix you want to know the trace of. This suffices as a definition, at least. You probably need to make a choice to show it is the normal definition of trace.
Sep
5
comment Recognizing Simplicial (Quasi)Fibrations
I suppose in general (the hard version of) your question is difficult. For example, if $E$ and $B$ are $K(\pi,1)$'s your question is asking whether $E$ covers $B$ or not, which for the groups amounts to asking whether or not one group can be found as a subgroup of another -- the embedding problem for groups. Although this is not what you're asking, if you were to go further and ask for a genuine fibre bundle, that is a very hard problem. For high-dimensional manifolds there is a (difficult to compute) complete obstruction called the Farrell Fibering Theorem.
Sep
4
comment Existence of orientation preserving, finite order self homeomorphism on a genus 2 surface without fixed point
You can view the classification of Seifert fibred spaces as a dictionary for enumerating conjugacy classes of finite-order automorphisms of surfaces, with or without fixed points, it's up to you. With that tool it becomes a simple enumeration problem. You just have to determine precisely which Seifert fiber spaces fiber over the circle -- this means they have a horizonal incompressible surface.
Sep
3
reviewed Close Prime order elements in $GL(n,\mathbb{Z})$
Sep
3
comment Feynman integrals in algebraic geometry
This is somewhat of a borderline question for the forum. Generally "tell me about stuff" requests don't do very well. It might make sense to start a meta thread where you could refine your question beforehand.
Aug
27
reviewed Close Is real analytic function good enough (see problem)?
Aug
27
reviewed Close Generic coordinate system representations
Aug
15
comment What is parameterization of the trefoil knot surface in R³?
Or did you mean to say curve, and have a single-variable function?
Aug
8
reviewed Close A not defined notion in Friedman's article about Generalized Fubini's Theorem
Aug
8
reviewed Close Projection of a hypersurface from a point
Aug
8
reviewed Close Bingham's paper “Finite additivity vs countable additivity”
Aug
6
reviewed Close Computer Science applications of Roth's Theorem