Seminars Sorted by Series
Members’ Seminar
Some Equations and Games in Evolutionary Biology
The basic ingredients of Darwinian evolution, selection and
mutation, are very well described by simple mathematical models. In
1973, John Maynard Smith linked game theory with evolutionary
processes through the concept of evolutionarily stable...
NO TALK IN OBSERVANCE OF PRESIDENTS DAY
Does Infinite Cardinal Arithmetic Resemble Number Theory?
I will survey the development of modern infinite cardinal
arithmetic, focusing mainly on S. Shelah's algebraic pcf theory,
which was developed in the 1990s to provide upper bounds in
infinite cardinal arithmetic and turned out to have
applications...
Self-Avoiding Walk and Branched Polymers
I will introduce two basic problems in random geometry. A
self-avoiding walk is a sequence of steps in a d-dimensional
lattice with no self-intersections. If branching is allowed, it is
called a branched polymer. Using supersymmetry, one can map...
On Functoriality; on the Correspondence; and on Their Relation, Part 1
Robert Langlands
NO TALK IN LIEU OF WORKSHOP ON GALOIS REPRESENTATIONS
Mumford-Tate Groups and Domains
Phillip Griffiths
Symplectic Dynamics of Integrable Hamiltonian Systems
I will start with a review the basic notions of
Hamiltonian/symplectic vector field and of Hamiltonian/symplectic
group action, and the classical structure theorems of Kostant,
Atiyah, Guillemin-Sternberg and Delzant on Hamiltonian torus
actions...
Intersections of Polynomial Orbits, and a Dynamical Mordell-Lang Conjecture
Michael Zieve
Let f and g be nonlinear polynomials (in one variable) over the
complex numbers. I will show that, if there exist complex numbers a
and b for which the orbits {a, f(a), f(f(a)), ...} and {b, g(b),
g(g(b)), ...} have infinite intersection, then f and...
First Steps in Symplectic Dynamics
The modern theory of dynamical systems, as well as symplectic
geometry, have their origin with Poincare as one field with
integrated Ideas. Since then these fields developed quite
independently. Given the progress in these fields one can make a
good...
How to Construct Topological Invariants via Decompositions and the Symplectic Category
A Lagrangian correspondence is a Lagrangian submanifold in the
product of two symplectic manifolds. This generalizes the notion of
a symplectomorphism and was introduced by Weinstein in an attempt
to build a symplectic category. In joint work with...
The Mathematical Challenge of Large Networks
It is becoming more and more clear that many of the most
exciting structures of our world can be described as large
networks. The internet is perhaps the foremost example, modeled by
different networks (the physical internet, a network of
devices...
Strong and Weak Epsilon Nets and Their Applications
I will describe the notions of strong and weak epsilon nets in
range spaces, and explain briefly some of their many applications
in Discrete Geometry and Combinatorics, focusing on several recent
results in the investigation of the extremal...
Hilbert's Seventh Problem -- A Kaleidoscope
Gisbert Wuestholz
This is the talk I gave in Frankfurt which was organized to
commemorate the 100th birthday of Theodor Schneider. He and,
independently, A. Gelfond gave in 1934 two different solutions to
Hilbert's 7th problem. We shall give a historical panorama
of...
Bordered Floer homology is an invariant for three-manifolds with
boundary (or, more precisely, three-manifolds with parameterized
boundary), constructed using pseudo-holomorphic curve techniques.
The theory associates to a marked surface a...
Loop Products and Dynamics
A metric on a compact manifold M gives rise to a length function
on the free loop space LM whose critical points are the closed
geodesics on M in the given metric. Morse theory gives a link
between Hamiltonian dynamics and the topology of loop...
Symplectic Integration Algorithms
Towards Symplectic Algebraic Topology
Pseudo-holomorphic curves play a fundamental role in the study
of symplectic manifolds. Compactness and gluing theorems allow to
extract algebra out of analysis. The focus of this talk are certain
invariants which are constructed using pseudo...
The Role of Symmetry in Phase Transitions
Tom Spencer
This talk will review some theorems and conjectures about phase
transitions of interacting spin systems in statistical mechanics. A
phase transition may be thought of as a change in a typical spin
configuration from ordered state at low temperature...
Linear Equations in Primes and Nilpotent Groups
A classical theorem of Dirichlet establishes the existence of
infinitely many primes in arithmetic progressions, so long as there
are no local obstructions. In 2006 Green and Tao set up a program
for proving a vast generalization of this theorem...
Toward Enumerative Symplectic Topology
Enumerative geometry is a classical subject often concerned with
enumeration of complex curves of various types in projective
manifolds under suitable regularity conditions. However, these
conditions rarely hold. On the other hand, Gromov-Witten...
Topology vs Combinatorics of Line Arrangements
No seminar today -- IAS closed for Presidents' Day
Weakly Commensurable Arithmetic Groups and Isospectral Locally Symmetric Spaces
Andrei Rapinchuk and I have introduced a new notion of
``weak-commensurability’’ of subgroups of two semi-simple groups.
We have shown that existence of weakly-commensurable Zariski-dense
subgroups in semi-simple groups G_1 and G_2 lead to strong...
Local Correction of Codes and Euclidean Incidence Geometry
A classical theorem in Euclidean geometry asserts that if a set
of points has the property that every line through two of them
contains a third point, then they must all be on the same line. We
prove several approximate versions of this theorem (and...
No seminar today in lieu of Workshop on Symplectic Dynamics II
Polynomial Methods in Learning and Statistics
My goal in this talk is to survey some of the emerging
applications of polynomial methods in both learning and in
statistics. I will give two examples from my own work in which the
solution to well-studied problems in learning and statistics can
be...
The Heisenberg Algebra in Symplectic Algebraic Geometry
Anthony Licata
Part of geometric representation theory involves constructing
representations of algebras on the cohomology of algebraic
varieties. A great example of such a construction is the work of
Nakajima and Grojnowski, who independently constructed an...
Computations of Heegaard Floer Homologies
Heegaard Floer homology groups were recently introduced by
Ozsvath and Szabo to study properties of 3-manifolds and knots in
them. The definition of the invariants rests on delicate
holomorphic geometry, making the actual computations cumbersome.
In...
Parallel Repetition of Two Prover Games: A Survey
I will give an introduction to the problem of parallel
repetition of two-prover games and its applications and related
results in theoretical computer science (the PCP theorem, hardness
of approximation), mathematics (the geometry of foams,
tiling...
How to Find Periodic Orbits and Exotic Symplectic Manifolds
I will give an introduction to symplectic geometry and
Hamiltonian systems and then introduce an invariant called
symplectic cohomology. This has many applications in symplectic
geometry and has been used a lot especially in the last 5-10 years.
I...
Algebraic K-Theory Via Binary Complexes
Daniel Grayson
Quillen's higher K-groups, defined in 1971, paved the way for
motivic cohomology of algebraic varieties. Their definition as
homotopy groups of combinatorially constructed topological spaces
initially seems abstract and inaccessible. In this talk...
There will be no Members Seminar today.
Patching and Local-Global Principles
Patching methods are usually used to construct global objects
from more local ones. On the other hand, algebraic objects can
sometimes be understood from their local behavior, i.e., they
satisfy a local-global principle. In this talk, we explain a...
Proof of a 35 Year Old Conjecture for the Entropy of SU(2) Coherent States, and its Generalization.
Elliot Lieb
35 years ago Wehrl defined a classical entropy of a quantum
density matrix using Gaussian (Schr\"odinger, Bargmann, ...)
coherent states. This entropy, unlike other classical
approximations, has the virtue of being positive. He conjectured
that the...
This talk is intended for a general audience. The recent
discovery of an interpretation of constructive type theory into
abstract homotopy theory has led to a new approach to foundations
with both intrinsic geometric content and a computational...
A Computer-Checked Proof that the Fundamental Group of the Circle is the Integers
This talk is designed for a general mathematical audience; no
prior knowledge of type theory is presumed. One of the main goals
for the special year on univalent foundations is the development of
a logical formalism, called homotopy type theory...
Quantum Mechanics -- a Primer for Mathematicians
Juerg Froehlich
A general algebraic formalism for the mathematical modeling of
physical systems is sketched. This formalism is sufficiently
general to encompass classical and quantum-mechanical models. It is
then explained in which way quantum theory differs in an...
A Tricky Problem on Sums of Two Squares
A `toy model' for studying the probabilistic distribution of
nodal curves of eigenfunctions of linear operators arises from the
Laplacian on the standard real 2-torus. Here the eigenvalues are
associate to integers m that are sum of two squares...
There will be no Members Seminar today
There will be no Members Seminar today
Toeplitz Matrices and Determinants Under the Impetus of the Ising Model
Percy Deift
This is the first of two talks in which the speaker will discuss
the development of the theory of Toeplitz matrices and determinants
in response to questions arising in the analysis of the Ising model
of statistical mechanics. The first talk will be...
Quantum Ergodicity on Large Regular Graphs
Nalini Anantharaman
``Quantum ergodicity'' usually deals with the study of
eigenfunctions of the Laplacian on Riemannian manifolds, in the
high-frequency asymptotics. The rough idea is that, under certain
geometric assumptions (like negative curvature), the...
Homological Mirror Symmetry
Mirror symmetry is a deep conjectural relationship between
complex and symplectic geometry. It was first noticed by string
theorists. Mathematicians became interested in it when string
theorists used it to predict counts of curves on the quintic...
No seminar today -- IAS closed for Presidents' Day
Collective Phenomena, Collective Motion, and Collective Action in Ecological Systems
Fundamental questions in basic and applied ecology alike involve
complex adaptive systems, in which localized interactions among
individual agents give rise to emergent patterns that feed back to
affect individual behavior. In such systems, a...