Department of

# Mathematics

Seminar Calendar
for Topology Seminar events the year of Tuesday, February 23, 2021.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     January 2021          February 2021            March 2021
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2       1  2  3  4  5  6       1  2  3  4  5  6
3  4  5  6  7  8  9    7  8  9 10 11 12 13    7  8  9 10 11 12 13
10 11 12 13 14 15 16   14 15 16 17 18 19 20   14 15 16 17 18 19 20
17 18 19 20 21 22 23   21 22 23 24 25 26 27   21 22 23 24 25 26 27
24 25 26 27 28 29 30   28                     28 29 30 31
31


Tuesday, January 26, 2021

11:00 am in Via Zoom,Tuesday, January 26, 2021

#### Models of Lubin-Tate spectra via Real bordism theory

###### XiaoLin "Danny" Shi (University of Chicago)

Abstract: In this talk, we will present Real-oriented models of Lubin-Tate theories at p=2 and arbitrary heights. For these models, we give explicit formulas for the action of certain finite subgroups of the Morava stabilizer groups on the coefficient rings. This is an input necessary for future computations. The construction utilizes equivariant formal group laws associated with the norms of the Real bordism theory. As a consequence, we will describe how we can use these models to prove periodicity theorems for Lubin-Tate theories and set up an inductive approach to prove differentials in their slice spectral sequences. This talk is based on several joint projects with Agnès Beaudry, Jeremy Hahn, Mike Hill, Guchuan Li, Lennart Meier, Guozhen Wang, Zhouli Xu, and Mingcong Zeng.

Friday, January 29, 2021

4:00 pm in Zoom,Friday, January 29, 2021

#### Organizaitonal Meeting

###### Brannon (UIUC)

Abstract: We will be having our first organizational meeting. Please email basilio3(at)illinois(dot)edu for the Zoom information.

Tuesday, February 2, 2021

11:00 am in Zoom,Tuesday, February 2, 2021

#### Redshift in algebraic K-theory

###### Jeremy Hahn (MIT)

Abstract: I will describe work, joint with Dylan Wilson, about the redshifting properties of algebraic K-theory. I will focus on concrete examples, sketching proofs at the prime 2 that K(ko) has chromatic height 2 and K(tmf) has chromatic height 3.

For Zoom info, please email vesna@illinois.edu

Friday, February 12, 2021

4:00 pm in Zoom,Friday, February 12, 2021

#### Geometry of Knots

###### Brannon Basilio (UIUC)

Abstract: In this talk, we give an introduction to the geometry of knots. We first start with an example of how to decompose a knot complement into ideal tetrahedron and the conditions needed in order to obtain a hyperbolic structure on the tetrahedron. We then talk briefly of recent work in knot theory that uses this decomposition to obtain bounds on the hyperbolic volume of the knot complement. For Zoom information, please email basilio3 (at) illinois (dot) edu.

Tuesday, February 16, 2021

11:00 am in Zoom,Tuesday, February 16, 2021

#### Understanding accessible infinity-categories

###### Charles Rezk   [email] (UICU)

Abstract: Lurie introduced the very important notion of "accessible infinity-category", a generalization of the more classical notion of "accessible category". These are (infinity-)categories which are produced from two pieces of data: a small (infinity-)category and a "regular cardinal". The goal of this talk is to give an introduction to some of the ideas surrounding these, and to put them in a broader context.

Email vesna@illinois.edu for zoom info.

Tuesday, February 23, 2021

11:00 am in Zoom,Tuesday, February 23, 2021

#### The Borel C_2-equivariant K(1)-local sphere

###### William Balderrama (UIUC)

Abstract: I'll talk about the structure of the Borel C_2-equivariant K(1)-local sphere. This captures Im J-type phenomena in C_2-equivariant and R-motivic stable stems, and gives a concise approach to understanding the K(1)-localizations of stunted projective spaces.

Friday, February 26, 2021

4:00 pm in Zoom,Friday, February 26, 2021

#### A Length and an Area Walk Into a Bar Complex

###### Cameron Rudd (UIUC)

Abstract: I will discuss some occurrences of lengths and area in geometry.