Department of

# Mathematics

Seminar Calendar
for events the day of Monday, September 15, 2014.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     August 2014           September 2014          October 2014
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
3  4  5  6  7  8  9    7  8  9 10 11 12 13    5  6  7  8  9 10 11
10 11 12 13 14 15 16   14 15 16 17 18 19 20   12 13 14 15 16 17 18
17 18 19 20 21 22 23   21 22 23 24 25 26 27   19 20 21 22 23 24 25
24 25 26 27 28 29 30   28 29 30               26 27 28 29 30 31
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Monday, September 15, 2014

3:00 pm in 341 Altgeld Hall,Monday, September 15, 2014

#### On the persistence of closed Reeb orbits

###### Ely Kerman (UIUC Math)

Abstract: Reeb flows on contact manifolds are conjectured to always have closed orbits (the Weinstein Conjecture) and in many settings nontrivial lower bounds for their numbers are also expected. One obstacle to detecting many distinct closed orbits is the difficulty, well known from the study of closed geodesics, of distinguishing between simple and multiply covered orbits. In this talk I will introduce a $C^0$-distance between Reeb flows in the spirit of the Hofer norm and will describe a Floer theoretic proof that certain clusters of simple closed Reeb orbits must persist over surprisingly long distances. Among other things, this allows one to reprove a classic result of Ekeland and Lasry concerning multiple closed characteristics on convex hypersurfaces pinched between spheres of radius 1 and $\sqrt{2}$.

5:00 pm in 141 Altgeld Hall,Monday, September 15, 2014

#### Operator version of AGM inequality

###### Minyu Zhao

Abstract: Some new inqualities for the operator version of the arithmethric geometric mean inequality