All Questions

This is entirely a new area for me and I apologise in advance if the questions are silly. In Quillen's paper "Homotopy properties of the posets of non-trivial $p$-subgroup of a group" (see ...

Let $A,E,G:\mathrm{Set}_*\to\mathrm{Grp}_*$ be functors from pointed sets to (discrete) groups ($*=1$) together with natural transformations $i:A\to E, \ p: E\to G$ such that for any set $X$ \begin{...

It is well-known that the question whether a given connected simplicial complex (or simplicial set) is simply connected, is algorithmically undecidable as it can model the word problem. Assuming ...

Suppose that we know a discrete group acts on the geometric realization of a simplicial set. Is there some way to understand how the corresponding action works on the simplicial set? For example, if ...