This is the private area of David Roberts within the nLab.

I am a research associate (=postdoc) at the University of Adelaide in South Australia.

For my papers (including PhD thesis) please see here. This site is to gather teaching material, but also more ephemeral things.

#### Notes

• Theorem A for topological categories - this is a version of Quillen’s Theorem A for categories in $Top$. As a corollary, with a condition on the unit map of the codomain we get that geometric realisation of an $\mathcal{N}$-equivalence is a homotopy equivalence.

• Serre’s proof of the Grothendieck-Serre theorem on the Brauer group of a compact space. (to be uploaded).

#### Mathematical publishing

I have views about the current system of academic publishing, especially how it impacts mathematics. Two links of interest:

#### Less polished ideas

• Construction of an equivalence between crossed modules in finite groups, and crossed modules with finite homotopy groups. More generally, same thing with (finite groups) replaced with some sort of Serre class.

• cocompact proper Lie groupoids

#### Random ideas

Revised on June 30, 2014 20:17:50 by David Roberts (193.60.90.99)