University of Sydney
School of Mathematics and Statistics
Australian National University
On a theorem of Jan-Erik Roos.
Friday 1st September, 12-1pm, Carslaw 275.
In 1961, Jan-Erik Roos published a theorem about
the derived functors of the limit. We will begin by discussing
the theorem, its background, and its significance.
Then we will give a counterexample to Roos' 1961 theorem.
This amounts to constructing a certain abelian category with
strange behavior. Finally, we will discuss the background which
led to this strange abelian category, and how the study of
similar abelian categories leads to new structure theorems
for triangulated categories.