Previous Conferences & Workshops
Spectral gaps via additive combinatorics
Semyon Dyatlov
A spectral gap on a noncompact Riemannian manifold is an
asymptotic strip free of resonances (poles of the meromorphic
continuation of the resolvent of the Laplacian). The existence of
such gap implies exponential decay of linear waves, modulo a...
A characterization of functions with vanishing averages over products of disjoint sets
We characterize all complex-valued (Lebesgue) integrable
functions $f$ on $[0,1]^m$ such that $f$ vanishes when integrated
over the product of $m$ measurable sets which partition $[0,1]$ and
have prescribed Lebesgue measures $\\alpha_1,\\ldots,\...
Symplectic embeddings and infinite staircases
Ana Rita Pires
McDuff and Schlenk studied an embedding capacity function, which
describes when a 4-dimensional ellipsoid can symplectically embed
into a 4-ball. The graph of this function includes an infinite
staircase determined by the odd index Fibonacci numbers...
Optimal strong approximation for quadratic forms
4:30pm|Fine 214, Princeton University
For a non-degenerate integral quadratic form $F(x_1, \dots ,
x_d)$ in 5 (or more) variables, we prove an optimal strong
approximation theorem. Fix any compact subspace
$\Omega\subset\mathbb{R}^d$ of the affine quadric
$F(x_1,\dots,x_d)=1$. Suppose...
A graph coloring problem and its algebraic and topological consequences
Daniel Wise
I will first describe a simple graph coloring problem and survey
some examples of graphs for which the coloring problem has or has
no solution. I will then give a quick introduction to
Bestvina-Brady Morse theory. Finally, I will describe the...
2:00pm|Fine 801, Princeton University
Saul Schleimer
(Joint with Henry Segerman.) It is a theorem of Moise that every
three-manifold admits a triangulation, and thus infinitely many.
Thus, it can be difficult to learn anything really interesting
about the three-manifold from any given triangulation...
Applications of thin orbits
We will discuss some natural problems in arithmetic that can be
reformulated in terms of orbits of certain "thin" (semi)groups of
integer matrix groups.
A topological predictor of protein compressibility
5:00pm|David Rittenhouse Laboratory Room A4, University of Pennsylvania
A standard question in contemporary proteomics asks which
properties of proteins may be directly inferred from their
molecular structure. Using only X-Ray crystallography data (of the
type which is cataloged in the Protein Data Bank), I will
outline...
Metrics on the space of shapes, and applications to biology
3:30pm|David Rittenhouse Laboratory Room A4, University of Pennsylvania
The problem of comparing shapes turns up in different guises in
numerous fields. I will discuss a new metric on the space of smooth
Riemannian 2-spheres that is well suited for comparing geometric
similarity. The metric is based on a distortion...