## Time and location

The Ottawa-Carleton joint algebra seminar meets during the academic year approximately once per week at either The University of Ottawa or Carleton University. Unless otherwise indicated, time and location are as follows:

• University of Ottawa:  Monday, 1:00pm–2:00pm, STM 664
• Carleton University:  Monday, 1:00pm–2:00pm, HP 4325

## Talks

Date Speaker Title (click for abstract)
Jan 13 (O) Peter Latham (Ottawa)
Let G be the group of rational points of a connected reductive group over a p-adic field. Under very mild hypotheses on p, we have a complete, explicit classification of the irreducible complex representations of G, with many desirable properties—the classification is in terms of what Bushnell and Kutzko call typical representations. It's expected that this classification is, up to minor renormalization, the only one with such nice properties, but this is only currently known in a few special cases. I'll explain joint work with Monica Nevins which reduces the general case to some explicit questions about the geometry of the Bruhat–Tits building of G.
Jan 20 (O) Chris Dionne
In this talk we'll give an introduction to multi-point Seshadri constants for ample line bundles on smooth projective varieties, and discuss their relationship with the nef cone. We'll also go over the structure of the nef cone as described by a theorem of Mori, and show some explicit calculations for blow-ups of $$\mathbb{P}^1 \times \mathbb{P}^1$$ at an even number of points greater than eight.
Jan 27
Feb 3
Feb 10
Feb 24
Mar 2
Mar 9
Mar 16 (C) David Wehlau (Queen's)
TBD
Mar 23
Mar 30
Apr 6 (C) Nicholas Meadows (Haifa University)

Toda Brackets are a kind of higher homotopy operation, originally introduced by Toda to study unstable homotopy groups of spheres. They can be viewed as successive obstructions to rectifying a certain kind of homotopy commutative diagram. Baues, Blanc and their collaborators gave a more general definition of Toda brackets (and other higher homotopy operations) in pointed simplicial (model) categories.

In this talk will explain how to generalize their work further, defining Toda brackets (and an unstable analogue) in two different models of $(\infty, 1)$-categories: simplicially enriched categories and quasi-categories. We will also explain how to construct Bousfield-Kan type spectral sequences in quasi-categories satisfying certain assumptions, and explain how the differentials in these spectral sequences can be described in terms of higher homotopy operations.

This is in progress work with David Blanc.

(O) = uOttawa, (C) = Carleton