Department of

# Mathematics

Seminar Calendar
for events the day of Friday, November 14, 2014.

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More information on this calendar program is available.
Questions regarding events or the calendar should be directed to Tori Corkery.
     October 2014          November 2014          December 2014
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Friday, November 14, 2014

4:00 pm in 243 Altgeld Hall,Friday, November 14, 2014

#### Topology and Geometry of Hyperplane Arrangements

###### Nathan Fieldsteel (UIUC Math)

Abstract: Hyperplane arrangements can be studied from a geometric or topological perspective, as well as from an algebraic or combinatorial one. We will discuss some of these perspectives and look at some examples. Our aim is to get a feel for the subject and maybe try to get a handle on the big picture. Time permitting, we look at a specific question about the topological complexity of an arrangement complement, and whether this invariant can be computed algebraically.

4:00 pm in 345 Altgeld Hall,Friday, November 14, 2014

#### On the equality $p = t.$

###### Justin Moore (Cornell University)

Abstract: Malliaris and Shelah, using inspiration and techniques coming from model theory, proved that the cardinal numbers p and t coincide. This solved one of the oldest remaining problems in set theory, one which predates the development of forcing. I will present a shorter argument of the main technical result of the proof that p = t, which is derived in part by notes of Juris Steprans on the Malliaris-Shelah proof.

4:30 pm in 239 Altgeld Hall,Friday, November 14, 2014

#### Department of Mathematics Social Hour

Abstract: The Department of Mathematics will hold a social hour gathering from 4:30-5:30 p.m. in 239 Altgeld Hall. Everyone in the department is welcome to attend.