[csdm-rutgers] UPDATE: Mathematics Seminars -- Week of September 22, 2014

[Anthony Pulido]

INSTITUTE FOR ADVANCED STUDY
School of Mathematics
Princeton, NJ 08540

Mathematics Seminars
Week of September 22, 2014

Seminar added on Thursday 9/25, 11:15-12:15.

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To view mathematics in titles and abstracts, please click on the talk's link.
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Monday, September 22

Computer Science/Discrete Mathematics Seminar I
Topic: 		Colouring graphs with no odd holes
Speaker: 	Paul Seymour, Princeton University
Time/Room: 	11:15am - 12:15pm/S-101
Abstract Link:	http://www.math.ias.edu/seminars/abstract?event=52284

Members' Seminar
		No seminar today
Speaker: 	No seminar today
Time/Room: 	 -



Tuesday, September 23

Computer Science/Discrete Mathematics Seminar II
Topic: 		Uniform words are primitive
Speaker: 	Doron Puder, Member, School of Mathematics
Time/Room: 	10:30am - 12:30pm/S-101
Abstract Link:	http://www.math.ias.edu/seminars/abstract?event=52414

Short talks by postdoctoral members
Topic: 		Exponential Separation of Information and Communication
Speaker: 	Gillat Kol, Member, School of Mathematics
Time/Room: 	2:00pm - 2:15pm/S-101

Topic: 		Overtwisted contact structures
Speaker: 	Matthew Borman, Member, School of Mathematics
Time/Room: 	2:15pm - 2:30pm/S-101

Topic: 		Arithmetic statistics over number fields and function fields
Speaker: 	Alexei Entin, Member, School of Mathematics
Time/Room: 	4:00pm - 4:15pm/S-101

Topic: 		Analysis of Boolean Functions on Association Schemes
Speaker: 	Yuval Filmus, Member, School of Mathematics
Time/Room: 	4:15pm - 4:30pm/S-101

Topic: 		Instability and stratifications of moduli problems in algebraic geometry
Speaker: 	Daniel Halpern-Leistner, Member, School of Mathematics
Time/Room: 	4:30pm - 4:45pm/S-101



Thursday, September 25

Topology of Algebraic Varieties
Topic: 		Symmetric differentials and the fundamental group
Speaker: 	Burt Totaro, University of California, Los Angeles; Member, School of Mathematics
Time/Room: 	11:15am - 12:15pm/S-114 (Martin L. Leibowitz Room)
Abstract Link:	http://www.math.ias.edu/seminars/abstract?event=63444

Princeton/IAS Symplectic Geometry Seminar
Topic: 		Symplectic fillings and star surgery
Speaker: 	Laura Starkston, University of Texas, Austin
Time/Room: 	11:30am - 12:30pm/S-101
Abstract Link:	http://www.math.ias.edu/seminars/abstract?event=63065

Short talks by postdoctoral members
Topic: 		Algebraic cycles on holomorphic symplectic varieties
Speaker: 	Lie Fu, Member, School of Mathematics
Time/Room: 	2:00pm - 2:15pm/S-101

Topic: 		Local relative trace formulas
Speaker: 	Raphaël Beuzart-Plessis, Member, School of Mathematics
Time/Room: 	2:15pm - 2:30pm/S-101

Topic: 		Rota's conjecture and positivity of algebraic cycles in toric varieties
Speaker: 	June Huh, Member, School of Mathematics
Time/Room: 	2:30pm - 2:45pm/S-101

Topic: 		Counting the nodal domains of the Laplacian eigenfunctions on surfaces
Speaker: 	Junehyuk Jung, Member, School of Mathematics
Time/Room: 	4:00pm - 4:15pm/S-101

Topic: 		The 3-Selmer rank in families of cubic twists of elliptic curves
Speaker: 	Nayoung Kim, Member, School of Mathematics
Time/Room: 	4:15pm - 4:30pm/S-101

Topic: 		High dimensional expanders
Speaker: 	Ori Parzanchevski, Member, School of Mathematics
Time/Room: 	4:30pm - 4:45pm/S-101



Friday, September 26

Short talks by postdoctoral members
Topic: 		The polynomial Freiman-Ruzsa conjecture in additive combinatorics and its applications in computational complexity
Speaker: 	Noga Ron-Zewi, Member, School of Mathematics
Time/Room: 	2:00pm - 2:15pm/S-101

Topic: 		From the Fukaya category to curve counts via Hodge theory
Speaker: 	Nicholas Sheridan, Veblen Research Instructor, School of Mathematics
Time/Room: 	2:15pm - 2:30pm/S-101

Topic: 		Fourier-Jacobi periods and central value of \(L\)-functions
Speaker: 	Hang Xue, Member, School of Mathematics
Time/Room: 	2:30pm - 2:45pm/S-101

1 Colouring graphs with no odd holes
    Paul Seymour

The chromatic number \(k(G)\) of a graph \(G\) is always at least the 
size of its largest clique (denoted by \(w(G)\)), and there are graphs 
with \(w(G)=2\) and \(k(G)\) arbitrarily large. On the other hand, the 
perfect graph theorem asserts that if neither \(G\) nor its complement 
has an odd hole, then \(k(G)=w(G)\). (An ``odd hole" is an induced cycle 
of odd length at least five.) What happens in between? With Alex Scott, 
we have just proved the following, a 1985 conjecture of Gyarfas: For 
graphs \(G\) with no odd hole, \(k(G)\) is bounded by a function of 
\(w(G)\).

http://www.math.ias.edu/seminars/abstract?event=52284

2 Uniform words are primitive
    Doron Puder

Let \(G\) be a finite group, and let \(a\), \(b\), \(c\),... be 
independent random elements of \(G\), chosen at uniform distribution. 
What is the distribution of the element obtained by a fixed word in the 
letters \(a\), \(b\), \(c\),..., such as \(ab\), \(a^2\), or 
\(aba^{-2}b^{-1}\)? More concretely, do these new random elements have 
uniform distribution? In general, a word \(w\) in the free group \(F_k\) 
is called uniform if it induces the uniform distribution on every finite 
group \(G\). So which words are uniform? A large set of uniform words 
are those which are 'primitive' in the free group \(F_k\), namely those 
belonging to some basis (a free generating set) of \(F_k\). Several 
mathematicians have conjectured that primitive words are the only 
uniform words. In a joint work with O. Parzanchevski, we prove this 
conjecture. I will try to define and explain all notions, and give many 
details from the proof. I will also present related open problems.

http://www.math.ias.edu/seminars/abstract?event=52414

3 Symmetric differentials and the fundamental group
    Burt Totaro

Esnault asked whether a smooth complex projective variety with infinite 
fundamental group has a nonzero symmetric differential, meaning a 
section of some symmetric power of the cotangent bundle. We prove a 
partial result in this direction, using Simpson's theory of 
representations of the fundamental group. The result gives some 
information on Kobayashi hyperbolicity for these varieties. (Joint with 
Yohan Brunebarbe and Bruno Klingler)

http://www.math.ias.edu/seminars/abstract?event=63444

4 Symplectic fillings and star surgery
    Laura Starkston

Although the existence of a symplectic filling is well-understood for 
many contact 3-manifolds, complete classifications of all symplectic 
fillings of a particular contact manifold are more rare. Relying on a 
recognition theorem of McDuff for closed symplectic manifolds, we can 
understand this classification for certain Seifert fibered spaces with 
their canonical contact structures. In fact, even without complete 
classification statements, the techniques used can suggest constructions 
of symplectic fillings with interesting topology. These fillings can be 
used in cut-and-paste operations called star surgery to construct 
examples of exotic 4-manifolds.

http://www.math.ias.edu/seminars/abstract?event=63065

IAS Math Seminars Home Page:
http://www.math.ias.edu/seminars