University of California, Riverside - Department of Mathematics

Groupoids Seminar

Organizer: Aviv Censor


The UCR Groupoids Seminar started meeting in the Fall 2008 quarter. The seminar's original objective was to focus attention on a very interdisciplinary and intriguing field of mathematics, in view of the Groupoidfest 2008 conference hosted at UCR in November 2008.

Being successful in attracting participants and interest, the seminar continues running regularly in 2009-2010. The first meeting of the Spring 2010 quarter will be on March 30, 2010.

In Spring 2010, the UCR Groupoids Seminar will meet on Tuesdays at 12:40 - 2:00 pm in room 268, Surge building.

Spring 2010

March 30
Speaker: Daniele Grandini
Title: Geometry and Groupoids (cont.)
April 6
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 4: from Pseudogroups to Groupoids via Germs
April 13
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 4 (cont.): from Pseudogroups to Groupoids via Germs
April 20
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 5: Jets
April 27
Speaker: Chris Rogers
Title: Introduction to Differentiable Stacks
May 4
No meeting
May 11
Equivariant Homotopy and Orbifold Invariants
Laura Scull, Fort Lewis College
Abstract
May 18
Speaker: Chris Rogers
Title: Introduction to Differentiable Stacks (cont.)
May 25
Speaker: Aviv Censor
Title: Inverse Semigroups and Groupoids



Previous Quarters

Winter 2010

January 7
Organizational meeting
January 14
Speaker: Jacob West
Title: The Fundamental Groupoid Revisited
January 21
Speaker: Julie Bergner
Title: Classical Fixed Point Theory
January 28
Speaker: Julie Bergner
Title: Ringoids in Fixed Point Theory
February 4
Speaker: Chris Carlson
Title: From Manifolds to Orbifolds: A Topological Excursion
Abstract
February 11
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 1: Orbifolds
Abstract
February 18
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 2: from Group(oid)s to Orbifolds
Abstract
February 25
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 2: from Group(oid)s to Orbifolds (cont.)
March 4
Speaker: Daniele Grandini
Title: Geometry and Groupoids, part 3: Pseudogroups
March 11
Speaker: Christopher Walker
Title: Groupoid Cardinality and Egyptian Fractions

Fall 2009

September 24
Organizational meeting
October 1
Speaker: Christopher Walker
Title: Groupoidification of Hall Algebras
October 8
Speaker: Christopher Walker
Title: Groupoidification of Hall Algebras (cont.)
October 15
Speaker: Aviv Censor
Title: Topological Groupoids and Haar Systems
October 22
Speaker 1: Aviv Censor
Title: Towards Topological Degroupoidification
Abstract
Speaker 2: Christopher Walker
Title: A Categorification of Hall Algebras
Abstract
October 29
Speaker: Daniele Grandini
Title: Measured Groupoids
November 5
Speaker: Daniele Grandini
Title: Measured Groupoids (cont.)
November 12
Crossed Modules of Hopf Algebras
Yael Fregier, University of Luxembourg
Abstract
November 19
Speaker: Aviv Censor
Title: Can topological & measure-theoretic degroupoidification be made easy?
November 26
Thanksgiving
December 3
Speaker: Edward Burkard
Title: Wedderburn's Theorem for Ringoids

Spring 2009

April 9
Speaker: Julie Bergner
Title: Simplicial Complexes, Simplicial Sets, and Nerves of Groupoids
April 16
Speaker: Julie Bergner
Title: Simplicial Complexes, Simplicial Sets, and Nerves of Groupoids (cont.)
April 23
Speaker: Julie Bergner
Title: Simplicial Complexes, Simplicial Sets, and Nerves of Groupoids (cont.)
April 30
Speaker: Edward Burkard
Title: Ringoids
May 7
Speaker: Christopher Walker
Title: Introduction to Groupoidification
May 14
Groupoids for Classical Field Theories with Symmetry
Joris Vankerschaver, Caltech
Abstract
(Joint meeting with FRG, in Surge 268)
May 21
Speaker: Christopher Walker
Title: Introduction to Groupoidification (cont.)
May 28
Speaker: Aviv Censor
Title: Towards Topological Degroupoidification
Abstract

Winter 2009

January 8
Speaker: Aviv Censor
Title: Groupoids Revisited
January 15
Speaker: Aviv Censor
Title: Groupoid Cohmology and Twisted Groupoid C*-algebras (cont.)
January 22
Speaker: Aviv Censor
Title: Groupoid Actions and Equivalence of Groupoids
January 29
Speaker: Vasiliy Dolgushev
Title: The Goldman-Millson Groupoid of a Differential Graded Lie Algebra
Abstract
Febuary 5
Speaker: Aviv Censor
Title: Groupoid Actions and Equivalence of Groupoids (cont.)
Febuary 12
Speaker: Daniele Grandini
Title: Differentiating Lie Groupoids
Febuary 19
Speaker: Daniele Grandini
Title: Differentiating Lie Groupoids (cont.)
Febuary 26
Speaker: Daniele Grandini
Title: Differentiating Lie Groupoids (cont.)
March 5
Speaker: Aviv Censor
Title: Equivalence vs. Similarity of Groupoids
March 12
Speaker: Aviv Censor
Title: Equivalence vs. Similarity of Groupoids (cont.)

Fall 2008

A description of the seminar's objectives can be found in the Groupoid Seminar Info Page.

September 25
Speaker: Aviv Censor
Title: Groupoids Capture Local Symmetries
October 2
Speaker: Aviv Censor
Title: The Axiomatic Definition and Many Examples
October 9
Speaker: Aviv Censor
Title: Terminology, Properties, and More Examples
October 16
Speaker: Aviv Censor
Title: Some Classification Theorems, Topology and Measure
October 23
Speaker: Julie Bergner
Title: The Fundamental Groupoid
October 30
Speaker: Aviv Censor
Title: Etale Groupoids and their C*-Algebras
November 6
Speaker 1: Alex Hoffnung
Title: A Categorification of Hecke Algebras
Speaker 2: Chris Walker
Title: Groupoidified Linear Algebra
November 13
Speaker: Daniele Grandini
Title: Lie Groupoids and Lie Algebroids (part 1)
November 20
Speaker: Daniele Grandini
Title: Lie Groupoids and Lie Algebroids (part 2)
November 21
Special Colloquium:
Groupoid Symmetry for Einstein's Equations?
Alan Weinstein, UC Berkeley
Abstract
November 22-23

Groupoidfest 2008

December 4
Speaker: Aviv Censor
Title: Groupoid Cohmology and Twisted Groupoid C*-algebras