Department of

# Mathematics

Seminar Calendar
for events the day of Monday, October 12, 2020.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
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Monday, October 12, 2020

11:00 am in go.illinois.edu/AGreatConversation ,Monday, October 12, 2020

#### The Empowered University: Shared Leadership in Challenging Times

###### Freeman Hrabowski (University of Maryland, Baltimore County)

Abstract: Please join Robert J. Jones, Chancellor at the University of Illinois Urbana-Champaign for the first installment of “A Great Conversation” with Freeman Hrabowski, President of the University of Maryland, Baltimore County (UMBC). Hrabowski is an alumnus of the UIUC Mathematics Department. Hrabowski will present “The Empowered University: Shared Leadership in Challenging Times,” an examination of “how university communities can support academic success by cultivating an empowering institutional culture.” Hrabowski and Jones will relate their own educational experiences as scholars and higher education leaders, the state of higher education today, increasing access to education and the responsibility of training the next generation of world leaders.

3:00 pm in Zoom,Monday, October 12, 2020

#### Picard groups in homotopy theory

###### Sai (UIUC)

Abstract: A very classical invariant of a commutative ring $R$ is the Picard group. In this talk I will introduce some "interesting" Picard groups in homotopy theory and some techniques to compute them. Please email vb8 at illinois dot edu for the zoom details.

3:00 pm in zoom,Monday, October 12, 2020

#### The semitoric octagon

###### Sonja Hohloch (University of Antwerp)

Abstract: Roughly speaking, a semitoric system is a completely integrable Hamiltonian system on a 4-dimensional symplectic manifold that admits only nondegenerate singularities without hyperbolic components and whose flow gives rise to an (S^1×R)-action. Semitoric systems have been symplectically classified a decade ago by Pelayo & Vu Ngoc by means of five invariants. Recently, there has been made considerable progress by various authors concerning the computation of these invariants. In this talk, we will give a brief introduction to semitoric systems before focusing on a recent, intuitive family of semitoric systems that allows for explicit observation of bifurcation behaviour such as ‘nodal trades’ between focus-focus and elliptic-elliptic singularities and other interesting geometric-topological features related to singularities and bifurcations. The latter part is based on a joint work with A. De Meulenaere.

5:00 pm in Altgeld Hall,Monday, October 12, 2020

#### Quantum error correction

###### Yidong Chen (UIUC physics)

Abstract: This talk will discuss operator error correction and how this was used to understand properties of black holes. https://illinois.zoom.us/j/87316015196?pwd=dU9XZE0rbVZQeWRyY2w2TklDR051dz09

5:00 pm in Altgeld Hall,Monday, October 12, 2020

#### More on recovery

Abstract: We will discover recovery theorems and complex interpolation.