Stacks and Groupoids

University of Colorado at Boulder

Seminar on

STACKS AND GROUPOIDS

Fall 2009: Wednesdays 4:00-5:00 in MATH 350

This is a working seminar meant to introduce algebraic and smooth stacks, groupoids, and orbifolds. The seminar will be held in Mathematics 350. The mathematics department is at the corner of Colorado Ave and Folsom St. For a map of the campus, click here. For parking instructions, click here.

Schedule of upcoming talks:

Click on the title of a talk for the abstract (if available).

August 26	Sebastian Casalaina-Martin and Markus Pflaum	Organizational meeting
September 2	Sebastian Casalaina-Martin	An introduction to stacks
September 9	Sebastian Casalaina-Martin	Stacks for everyone
September 16	Markus Pflaum	Category theory, adjoint functors, and the Yoneda Lemma
September 23	Markus Pflaum	Category theory, adjoint functors, and the Yoneda Lemma continued
September 30	Markus Pflaum	Grothendieck topologies, sites, and sheaves
October 7	NO SEMINAR	DELONG LECTURES OCTOBER 5, 7, 9 "Logic, Lie Theory and Operads"
October 14	Markus Pflaum	Grothendieck topologies, sites, and sheaves continued
October 21	Arlan Ramsay	Introduction to groupoids
October 24-25	GROUPOIDFEST	GROUPOIDFEST
October 28	SNOW DAY	SNOW DAY
November 4	Arlan Ramsay	Things to do with groupoids
November 11	Arlan Ramsay	Groupoids continued
November 18	Christopher Seaton	Introduction to orbifolds and orbifold groupoids
November 25	NO SEMINAR	THANKSGIVING BREAK
December 2	Carla Farsi	Introduction to orbifolds as stacks

NEXT SEMESTER'S SEMINAR

References:

Stacks for Everybody by Fantechi
Algebraic Stacks by Fulton et al.
FGA Explained by Fantechi et al. (First chapter by Vistoli on the arxiv)
Topological and Smooth Stacks by Metzler

Some further references:

The irreducibility of the space of curves of a given genus by Deligne-Mumford
Picard groups of moduli problems by Mumford
Intersection theory on algebraic stacks and their moduli spaces by Vistoli
Introduction to the language of stacks and gerbes by Moerdijk
Orbifolds as groupoids: an introduction by Moerdijk
Sheaves in geometry and logic: a first introduction to topos theory by Mac Lane-Moerdijk
Orbifolds as stacks? by Lerman

This seminar is being organized by Sebastian Casalaina-Martin and Markus Pflaum. The web page is maintained by Sebastian Caslaina-Martin; it was shamelessly copied from Izzet Coskun's page, which in turn was shamelessly copied from Jason Starr's page, which in turn was shamelessly copied from Ravi Vakil's page, which in turn was shamelessly copied from Pasha Belorousski's page at the University of Michigan.