Department of

# Mathematics

Seminar Calendar
for events the day of Monday, February 23, 2015.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     January 2015          February 2015            March 2015
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1  2  3    1  2  3  4  5  6  7    1  2  3  4  5  6  7
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Monday, February 23, 2015

12:00 pm in 341 AH,Monday, February 23, 2015

#### Multigraphs to symplectic circle actions

###### Donghoon Jang (UIUC Math)

Abstract: Consider a symplectic circle action on a compact symplectic manifold with isolated fixed points. We can associate a directed multigraph to the manifold. Y. Karshon proved that if the dimension of the manifold is four, this multigraph completely determines the manifold up to equivariant symplectomorphism. We prove that we can associate a multigraph that does not have any loops. As an application, we complete the proof of the symplectic Petrie's conjecture for eight dimensional manifolds. This is a joint work with S. Tolman. arXiv:1408.6580.

4:00 pm in 145 Altgeld Hall,Monday, February 23, 2015

#### Introduction to elimination theory and implicitization

###### Eliana Duarte   [email] (UIUC Math)

Abstract: In this talk I will introduce the tools from commutative algebra that allow us to approach the implicitization problem using Rees-algebra techniques. These include local cohomology, Fitting ideals, MacRae’s invariants among others. The goal is to explain the big picture of how these tools interact with each other in the context of the implicitization problem.

5:00 pm in 241 Altgeld Hall,Monday, February 23, 2015

#### Khintchine p<1

###### Li Gao

Abstract: We continue the proof-