Yorkshire and Midlands Category Theory Seminar
Meeting 25
September 14th, 2021
Hosted on Zoom by the University of Leeds
Supported by the London Mathematical Society

Schedule (all UK BST times)

15:00-16:00 Caterina Consani 
(Johns Hopkins University) - On absolute geometry
16:00-16:05 Break
André Joyal (Université du Québec à Montréal) - A 2-categorical model of 1-cobordisms and the cyclic category Λ
17:05-17:10 Break
Peter May (University of Chicago) - A graded monoid of multicategorical 2-monads
18:10-18:30 Discussion

All talks are 50 minutes followed by 10 minutes of questions.


Speaker: Caterina Consani  (Johns Hopkins University)
Title: On absolute geometry.

Abstract: The talk will overview some geometric constructions aiming to define the notion of the absolute geometric point and  the arithmetic over it (joint with A. Connes).
Slides: here

Speaker: André Joyal (Université du Québec à Montréal)
Title: A 2-categorical model of 1-cobordisms and the cyclic category Λ.
Abstract: See here.

Peter May (University of Chicago)
Title: A graded monoid of multicategorical 2-monads
Abstract: I will present some general category theory that grew out of equivariant muliplicative infinite loop space theory.  We start from operads in a suitable 2-category of internal categories. Such operads give rise to categories of operators. With suitable multiplicative structure, algebras over these give "symmetric monoidal graded 2-categories", which have associated multicategories.  These structures arise "in nature", at least if nature includes stable homotopy theory.  From this starting point, we construct graded multicategories of 2-monads (the monoids of the title) and show how to use Lack's codescent objects to simultaneously strictify and simplify this structure, making it relatively concrete.  The construction eliminates all pseudofunctors from the picture and reduces from general categories of operators to the simplest possible one, namely that given by the category of finite based sets.
Slides: here.


Nicola Gambino (University of Leeds)
Simona Paoli (University of Aberdeen)
Steve Vickers (University of Birmingham)

Page last modified on September 15th, 2021 by Nicola Gambino