bio  website  staff.ncl.ac.uk/mark.grant 

location  Aberdeen, United Kingdom  
age  
visits  member for  4 years, 4 months 
seen  7 hours ago  
stats  profile views  4,312 
Lecturer at University of Aberdeen, with interests in Algebraic and Differential Topology and their applications.
23h

awarded  Nice Question 
2d

comment 
Homotopical nilpotency
I don't know that I would expect such a characterization to exist, given that for groups the condition of being nilpotent of class 2 already seems quite elementary. 
Nov 20 
revised 
Configuration space like subspace of sphere product
added 2 characters in body 
Nov 20 
comment 
Configuration space like subspace of sphere product
I think the algebraic map actually goes to $\mathbb{R}^{n+1}$, hence the discrepancy in our dimensions. 
Nov 20 
answered  Configuration space like subspace of sphere product 
Nov 19 
comment 
Robotics, Cryptography, and Genetics applications of Grothendieck's work?
It may be worth noting that in that chapter Farber is surveying work of Gal: journals.impan.pl/cgibin/doi?cm8914 
Nov 14 
answered  Definition of Milnor exact sequence and complexoriented generalized cohomology of $\mathbb{C}P^{\infty}$ 
Nov 12 
revised 
Realization of second StiefelWhitney class
changed i to 1 
Nov 12 
answered  Realization of second StiefelWhitney class 
Nov 12 
comment 
Degree of Map between Pseudomanifold
I presume that you can prove welldefinedness in the same way as in the smooth case (by showing that it's homotopy invariant and that any $n$simplex is mapped onto any other $n$simplex by a homeomorphism isotopic to the identity) but I haven't time to check the details. By the way, if $N$ is not compact then the degree will be zero (since $f(M)$ is compact so $f$ is not surjective). Milnor notes this on p.20). 
Nov 12 
comment 
Degree of Map between Pseudomanifold
@gaoxinge: I don't see why not. If $M$ is compact, then the inverse image of any simplex in $N$ under a simplicial map will be a finite union of simplices. So as long as $M$ and $N$ are oriented, we get a finite sum of $+1$s and $1$s. 
Nov 12 
comment 
Degree of Map between Pseudomanifold
I think you can define the degree to be as in Exercise F.1 on Spanier page 207 (which is entirely analogous to how Milnor does it in the smooth case). The point is your pseudo manifold doesn't have to be finite to have an orientation. 
Nov 7 
comment 
Homotopy groups of $MO(2)$
Thank you, both. Which version of the unstable Adams spectral sequence are you using, Tyler? I would very much like to check what $\pi_7$ is, if possible. 
Nov 6 
asked  Homotopy groups of $MO(2)$ 
Nov 6 
comment 
The relation between group cohomology and the cohomology of the classifying space
Are you familiar with Stasheff's article maths.ed.ac.uk/~aar/papers/stasheff5.pdf ? The references there might answer your question. 
Oct 14 
accepted  Minimal models with local coefficients 
Sep 30 
awarded  Explainer 
Sep 7 
awarded  Necromancer 
Sep 7 
comment 
Idea and intuition behind Penrose transform
It might help to say why the Wikipedia page doesn't do what you want. 
Sep 6 
comment 
the algebraic theory of obstruction of a homology theory
The obstruction is the submodule $\operatorname{Im} (d\circ d)$. Without more context it seems difficult to say more. 