Ottawa-Carleton joint algebra seminar (Winter 2013)

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 is as follows:

University of Ottawa: Tuesdays, 4:00pm–5:00pm, KED B015
Carleton University: TBA

For information on the seminar in past semesters, click here. To schedule a talk, please contact Alistair Savage.

Talks

For a complete listing of all talks at the University of Ottawa, click here.

Date	Speaker	Title (click on titles to show/hide abstracts)
Jan 15 (O)	Kirill Zaynullin (Ottawa)	Exceptional collections of line bundles on projective homogeneous varieties Exceptional collections of line bundles on projective homogeneous varieties Abstract: The existence question for full exceptional collections in the bounded derived category of coherent sheaves of a smooth projective variety X goes back to the foundational results of Beilinson and Bernstein-Gelfand-Gelfand when X is the projective space. The works of Kapranov in 80's suggested that the structure of projective homogeneous variety on X should imply the existence of full exceptional collections. We construct new examples of exceptional collections of line bundles on the variety of Borel subgroups of a split semisimple linear algebraic group G of rank 2 over a field. We exhibit exceptional collections of the expected length for Dynkin types A₂ and B₂=C₂ and prove that no such collection exists for type G₂. This settles the question of the existence of full exceptional collections of line bundles on projective homogeneous G-varieties for split linear algebraic groups G of rank at most 2. This is a report on the joint paper with A. Ananyevskiy, A. Auel and S. Garibaldi.
Jan 22 (O)	Fabrizio Donzelli (Ottawa)	Makar-Limanov invariant, Derksen invariant and flexible varieties Makar-Limanov invariant, Derksen invariant and flexible varieties Abstract: Let X be an affine algebraic variety. I will introduce two invariants built out of kernels of locally nilpotent derivations on X and relate them to the geometric notions of flexibility and infinite-transitivity.
Jan 29
Feb 5	Wanshun Wong (Fields Institute)	An introduction to essential dimension An introduction to essential dimension Abstract: Informally speaking, essential dimension is the smallest number of independent parameters needed to describe an algebraic object. In this talk I will give the definition of essential dimension, and some examples showing how essential dimension is connected to other problems in algebra. In particular I will focus on the essential dimension of finite cyclic groups.
Feb 12
Feb 19	Study break
Feb 26
Mar 5
Mar 12
Mar 19
Mar 26	Nikita Semenov (University of Mainz)	Oriented cohomology theories and operations Oriented cohomology theories and operations Abstract: The idea of oriented cohomology theories goes back to Alexander Grothendieck. Levine, Morel, Panin, Smirnov et al. studied this notion in a systematic way. Recently Vishik obtained a combinatorial description of additive operations between two oriented cohomology theories satisfying certain assumptions. In my talk I am going to give an overview of some known facts about oriented cohomology theories and operations and introduce some new operations, which do not fit into Vishik's context.
Apr 2
Apr 9

(O) = uOttawa, (C) = Carleton