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OCTOBER 2009 |
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Department Colloquium |
Topic: |
Entropy in Measurable Dynamics |
Presenter: |
Lewis Bowen, Texas A & M |
Date: |
Wednesday, October 14, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
Abstract: |
In 1958, Kolmogorov defined the entropy of a probability measure preserving transformation. Entropy has since been central to the classification theory of measurable dynamics. In the 70s and 80s researchers extended entropy theory to measure preserving actions of amenable groups (Kieffer, Ornstein-Weiss). My recent work generalizes the entropy concept to actions of sofic groups; a class of groups that contains for example, all subgroups of GL(n,C). Applications include the classification of Bernoulli shifts over a free group, answering a question of Ornstein and Weiss. |
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Graduate Student Seminar |
Topic: |
Harmonic measure |
Presenter: |
Phil Sosoe, Princeton University |
Date: |
Thursday, October 15, 2009, Time: 12:30 p.m., Location: Fine Hall 314 |
Abstract: |
Harmonic measure is a measure on the boundary of domains in the complex plane whose associated integral generates the solution of the Dirichlet problem. I will explain Nevanlinna's "principle of harmonic measure", and give a number of examples of its use. Time allowing, I will discuss recent geometric results about harmonic measure, and its relation to other conformal invariants such as Beurling's extremal length. The talk will be completely elementary! |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
A priori bounds for bounded-primitive renormalization |
Presenter: |
Jeremy Kahn, SUNY Stony Brook |
Date: |
Thursday, October 15, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
Abstract: |
We say that an infinitely renormalizable quadratic polynomial has bounded-primitive type if we can find an infinite sequence of primitive renormalization times, such that the ratio between consecutive terms of the sequence is bounded. We prove that any such polynomial has the a priori bounds: there is a lower bound on the modulus of all renormalizations. This implies that the Mandelbrot set is locally connected at the associated parameter values. |
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Discrete Mathematics Seminar |
Topic: |
On the Schrijver-Seymour Conjecture |
Presenter: |
Matt DeVos, Simon Fraser |
Date: |
Thursday, October 15, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
Abstract: |
Two interesting classical results in combinatorial number theory are the Erdos-Ginzburg-Ziv Theorem and the Furedi-Kleitman Theorem. Fixing an abelian group G of order n, the former asserts that every sequence of 2n+1 elements of G has a length n subsequence which sums to 0, while the latter asserts that every edge-weighting of a complete graph of order n+1 with elements of G has a spanning tree of weight 0.
Schrijver and Seymour established a fascinating common generalization of these problems by considering a matroid M with a weighting w:E(M)->G. In this framework, they conjectured a natural lower bound on the number of distinct weights of bases. In addition to generalizing the above results, their conjecture (if true) would generalize Kneser's addition theorem for abelian groups. Schrijver and Seymour proved their conjecture in the special case when G has prime order, a result which implies the Erdos-Ginzburg-Ziv Theorem, among its numerous consequences. In this talk, I will discuss a proof of the Schrijver-Seymour conjecture in the special case when M is a matroid obtained from a uniform matroid by adding parallel elements. As I will detail, this result has numerous consequences for subsequence sums including two conjectures of Gao, Thangadurai, and Zhuang. This is joint work with B. Mohar and L. Goddyn. |
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Joint IAS/Princeton University Number Theory Seminar |
Topic: |
Volume estimates in analytic and adelic geometry |
Presenter: |
Antoine Chambert-Loir, IAS |
Date: |
Thursday, October 15, 2009, Time: 4:30 p.m., Location: IAS S-101 |
Abstract: |
The solution to many classical counting asymptotics problems in number theory goes by comparison with an analogous volume asumptotics. In a general setting, we establish asymptotic formulae for volumes of height balls in analytic varieties over local fields and in adelic points of algebraic varieties over number fields, relating the Mellin transforms of height functions to Igusa integrals and to global geometric invariants of the underlying variety. In the adelic setting, this involves the construction of general Tamagawa measures. This is joint work with Yuri Tschinkel (Courant). |
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Topology Seminar |
Topic: |
Immersed surfaces in closed hyperbolic 3-manifolds |
Presenter: |
Jeremy Kahn, SUNY Stony Brook |
Date: |
Thursday, October 15, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
Abstract: |
Given any closed hyperbolic 3-manifold $M$ and $\epsilon > 0$, we find a closed hyperbolic surface $S$ and a map $f\from S \to M$ such that $f$ lifts to a $1+\epsilon$-quasi-isometry from the universal cover of $S$ to the universal cover of $M$. This is joint work with Vladimir Markovic. |
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Extra Topology Seminar ***Please note special date, time, and location |
Topic: |
More on immersed surfaces in closed hyperbolic 3-manifolds |
Presenter: |
Jeremy Kahn, SUNY Stony Brook |
Date: |
Friday, October 16, 2009, Time: 1:30 p.m., Location: Fine Hall 401 |
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Differential Geometry and Geometric Analysis Seminar |
Topic: |
The Static Extension Problem in General Relativity |
Presenter: |
Marcus Khuri, SUNY Stony Brook |
Date: |
Friday, October 16, 2009, Time: 3:00 p.m., Location: Fine Hall 314 |
Abstract: |
There are several competing definitions of quasi-local mass in General Relativity. A very promising and natural candidate, proposed by Bartnik, seeks to localize the ADM or total mass. Fundamental to understanding Bartnik's construction, is the question of existence for a canonical geometric boundary value problem associated with the static vacuum Einstein equations. In this talk we report on joint work with M. Anderson, which answers this question affirmatively under the hypothesis of a certain nondegeneracy condition. We also show that uniqueness fails. |
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Differential Geometry and Geometric Analysis Seminar ***Please note special time |
Topic: |
Singularities, test configurations and constant scalar curvature Kahler metrics |
Presenter: |
Claudio Arezzo, University of Parma |
Date: |
Friday, October 16, 2009, Time: 4:00 p.m., Location: Fine Hall 314 |
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Analysis Seminar |
Topic: |
Counterexamples to the Strichartz estimates for the wave equation in domains |
Presenter: |
Oana Ivanovici, Johns Hopkins University |
Date: |
Monday, October 18, 2009, Time: 4:00 p.m., Location: Fine Hall 110 |
Abstract: |
We prove that the Strichartz estimates for the wave equation inside a strictly convex domain \Omega of dimension 2 suffer losses when compared to the usual case \mathbb{R}2, (at least for a subset of the usual range of indices) and this is due to microlocal phenomena such as caustics generated in arbitrariIly small time near the boundary. |
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Geometry, Representation Theory, and Moduli Seminar |
Topic: |
TBA |
Presenter: |
I. Setayesh, Princeton University |
Date: |
Monday, October 19, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
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Algebraic Geometry Seminar |
Topic: |
Algebraic curves with CM |
Presenter: |
Frans Oort, University of Utrecht |
Date: |
Tuesday, October 20, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
Abstract: |
Is every abelian variety isogenous with the Jacobian of an algebraic curve? We will study also several other questions in arithmetic geometry and show various implications. We will mention some solutions to these problems. |
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Department Colloquium |
Topic: |
Symplectic Embeddings and Continued Fractions |
Presenter: |
Dusa McDuff, Columbia University |
Date: |
Wednesday, October 21, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
Abstract: |
It has been known since the time of Gromov that questions about symplectic embeddings lie at the heart of symplectic geometry. This talk will mostly be about some recent work with Schlenk in which we work out precisely when a four dimensional ellipsoid embeds symplectically in a ball. This problem turns out to have unexpected relations with the properties of continued fractions and of exceptional curves in blow ups of the complex projective plane. It is also related to questions of lattice packing of planar triangles. |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
A pair correlation bound implies the Central Limit Theorem for Sinai Billiards |
Presenter: |
Mikko Stenlund, Courant Institute, NYU |
Date: |
Thursday, October 22, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
Abstract: |
It is an open problem in the study of dynamical systems whether fast decay of correlations alone is sufficient for the Central Limit Theorem (CLT) to hold. On the one hand, there are no examples of dynamical systems for which correlations decay quickly but the CLT fails. On the other, existing CLT proofs rely on statistical properties much stronger than correlation decay. In the talk I will discuss a prime class of physically relevant systems, called Sinai Billiards, and show that a single bound on correlations indeed implies the CLT directly. As a byproduct, the CLT is obtained for observables possessing remarkably little regularity. |
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Discrete Mathematics Seminar |
Topic: |
TBA |
Presenter: |
Wesley Pegden, Rutgers University |
Date: |
Thursday, October 22, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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Joint IAS/Princeton University Number Theory Seminar |
Topic: |
Torsion in the homology of arithmetic groups |
Presenter: |
Akshay Venkatesh, Stanford University |
Date: |
Thursday, October 22, 2009, Time: 4:30 p.m., Location: IAS S-101 |
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Topology Seminar |
Topic: |
Cusp volume of fibered 3-manifolds |
Presenter: |
David Futer, Temple |
Date: |
Thursday, October 22, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
Abstract: |
Consider a 3-manifold M that fibers over the circle, with fiber a punctured surface F. I will explain how the volume of a maximal cusp of M (in the hyperbolic metric) is determined up to a bounded constant by combinatorial properties of the arc complex of the fiber surface F. This is joint work with Saul Schleimer. |
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Differential Geometry and Geometric Analysis Seminar |
Topic: |
TBA |
Presenter: |
Sophie Chen, IAS |
Date: |
Friday, October 23, 2009, Time: 3:00 p.m., Location: Fine Hall 314 |
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Analysis Seminar |
Topic: |
Cocompact imbeddings and critical nonlinearity revisited |
Presenter: |
Kyril Tintarev, Uppsala University |
Date: |
Monday, October 26, 2009, Time: 4:00 p.m., Location: Fine Hall 110 |
Abstract: |
We introduce a notion of cocompact imbeddings relative to a group of linear isometries.We discuss the notion of critical Sobolev nonlinearity in connection with the usual dilation actions that make the (non-compact) limit Sobolev imbedding co-compact and yield solutions of Talenti type for semilinear elliptic equations with self-similar autonomous nonlinearities of critical growth.
We then consider similar dilation and translations groups for $H_01(B)$, where $B$ is a unit disk on a plane, which preserve the Sobolev norm, but do not preserve the Trudinger-Moser functional $\int e^{4\pi u2}$. We give then two examples of invariant critical nonlineairites that are stronger than Trudinger-Moser nonlinearity and lack the weakly continuity properties of the latter.
We give further examples of cocompactness in Sobolev spaces over manifolds, including subelliptic spaces over nilpotent Lie groups, as well as some interpolation results that lead to cocompactness of imbeddings of Besov spaces. This work is partially done in collaboration with Adimurthi, M. Cwikel and J.M. do O. |
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PACM Colloquium |
Topic: |
TBA |
Presenter: |
Howard Stone, Mechanical and Aerospace Engineering |
Date: |
Monday, October 26, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
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Geometry, Representation Theory, and Moduli Seminar |
Topic: |
TBA |
Presenter: |
V. Shende, Princeton University |
Date: |
Monday, October 26, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
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Analysis Seminar *** Please note special time |
Topic: |
TBA |
Presenter: |
Jared Speck, University of Cambridge |
Date: |
Monday, October 26, 2009, Time: 5:00 p.m., Location: Fine Hall 110 |
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Algebraic Geometry Seminar |
Topic: |
BGG correspondence and the cohomology of compact Kaehler manifolds |
Presenter: |
Mihnea Popa, UIC |
Date: |
Tuesday, October 27, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
Abstract: |
The cohomology algebra of the sheaf of holomorphic functions on a compact Kaehler manifold can be naturally viewed as a module over the exterior algebra of a vector space. A well-known result of Bernstein-Gel'fand-Gel'fand gives a correspondence between such "exterior" modules and linear complexes of modules over the symmetric algebra, i. e. the polynomial ring. I will explain how one can use a modern view on this correspondence, together with the Generic Vanishing theory developed by Green and Lazarsfeld via Hodge-theoretic methods, in order to understand subtle algebraic structures of the cohomology algebra. As a bonus, homological and commutative algebra tools can be applied on the polynomial ring side to obtain new inequalities for the holomorphic Euler characteristic and the Hodge numbers of compact Kaehler manifolds. This is joint work with R. Lazarsfeld. |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
TBA |
Presenter: |
Elon Lindenstrauss, Princeton University |
Date: |
Thursday, October 29, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
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Discrete Mathematics Seminar |
Topic: |
TBA |
Presenter: |
Julia Wolf, Rutgers University |
Date: |
Thursday, October 29, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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Joint IAS/Princeton University Number Theory Seminar |
Topic: |
Modularity lifting for n-dimensional ordinary Galois representations |
Presenter: |
David Geraghty, Harvard |
Date: |
Thursday, October 29, 2009, Time: 4:30 p.m., Location: Fine Hall 214 |
Abstract: |
I will discuss a generalization of the modularity lifting theorems of Clozel, Harris and Taylor to the case of ordinary Galois representations. The result is obtained by applying the Taylor-Wiles method (with innovations due to Kisin and Taylor) over a Hida family. A key step is to construct an appropriate ordinary lifting ring and determine its irreducible components. |
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Joint IAS/Princeton University Number Theory Seminar ***Please note special date, time, and location |
Topic: |
Generalizations of the Sato-Tate conjecture |
Presenter: |
David Geraghty, Harvard |
Date: |
Friday, October 30, 2009, Time: 4:00 p.m., Location: Fine Hall 322 |
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NOVEMBER 2009 |
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Geometry, Representation Theory, and Moduli Seminar |
Topic: |
TBA |
Presenter: |
L. Borisov, Rutgers University |
Date: |
Monday, November 2, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
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Joint IAS/Princeton University Number Theory Seminar |
Topic: |
Mean values with GL(2) times GL(3) functions |
Presenter: |
M. Young, TAMU |
Date: |
Thursday, November 5, 2009, Time: 4:30 p.m., Location: IAS S-101 |
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PACM Colloquium |
Topic: |
Geometry and Analysis of point sets in high dimensions |
Presenter: |
Mauro Maggioni, Duke University |
Date: |
Monday, November 9, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
Abstract: |
The analysis of high dimensional data sets is useful in a large variety of applications, from machine learning to dynamical systems: data sets are often modeled as low-dimensional, noisy data sets embedded in high-dimensional spaces; dynamical systems often have very high-dimensional state spaces but sometimes interesting dynamics occurs on low-dimensional sets. We discuss several problems associated with the analysis of the geometry of such sets, and with the approximation of functions on such sets, together with some solutions: in particular we discuss how to construct random walks on such data sets and perform multiscale analysis of them and their applications (especially to machine learning); how to construct robust coordinate systems for data sets; how to estimate reliably the intrinsic dimensionality of the data when only few noisy samples are available. |
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Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Matt DeLand, Stony Brook University |
Date: |
Tuesday, November 10, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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Mathematical Physics Seminar |
Topic: |
A variational model for crystals with defects |
Presenter: |
Mathieu Lewin, Université de Cergy-Pontoise |
Date: |
Tuesday, November 10, 2009, Time: 4:30 p.m., Location: Jadwin 343 |
Abstract: |
This talk will be devoted to the reduced Hartree-Fock model for crystals with defects.
The main idea is to describe at the same time the electrons bound by the defect and the (nonlinear) behavior of the infinite crystal. This leads to a bounded-below nonlinear functional whose variable is however an operator of infinite-rank.
I will provide the correct functional setting for this functional, state the existence of global-in-time solutions to the associated time-dependent Schrödinger equation, and discuss the existence, the properties and the stability of bound states. In particular I will define the dielectric permittivity of the perfect crystal and relate this to some properties of ground states. This is a review of joint works with Eric Cancès and Amélie Deleurence (Ecoledes Ponts, Paris). |
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Discrete Mathematics Seminar |
Topic: |
TBA |
Presenter: |
Andrew King, Columbia University |
Date: |
Thursday, November 12, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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Differential Geometry and Geometric Analysis Seminar |
Topic: |
TBA |
Presenter: |
Rick Schoen, Stanford University |
Date: |
Friday, November 13, 2009, Time: 3:00 p.m., Location: Fine Hall 314 |
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Joint Columbia-Courant-Princeton University Algebraic Geometry Seminar |
Topic: |
Analogue of the Narasimhan-Seshadri theorem in higher dimensions and holonomy |
Presenter: |
Vikraman Balaji, Chennai Mathematical Institute |
Date: |
Friday, November 13, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
Abstract: |
We will discuss some recent work on natural analogues of the Narasimhan-Seshadri theorem on higher dimensional varieties with some applications to stable bundles on surfaces. The classical result related stability of bundles on projective smooth curves with irreducible unitary representations of the fundamental group. Analogues of holonomy groups and their representations play the corresponding role. |
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Joint Columbia-Courant-Princeton University Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Tony Pantev, University of Pennsylvania |
Date: |
Friday, November 13, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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Analysis Seminar |
Topic: |
Astala's conjecture on Hausdorff measure distortion under planar quasiconformal mappings and related removability problems |
Presenter: |
Ignacio Uriarte-Tuero, Michigan State University |
Date: |
Monday, November 16, 2009, Time: 4:00 p.m., Location: Fine Hall 110 |
Abstract: |
In his celebrated paper on area distortion under planar quasiconformal mappings (Acta 1994) (for which he received the Salem prize), Astala proved that if $E$ is a compact set of Hausdorff dimension $d$ and $f$ is $K$-quasiconformal, then $fE$ has Hausdorff dimension at most $d' = \frac{2Kd}{2+(K-1)d}$, and that this result is sharp. He conjectured (Question 4.4) that if the Hausdorff measure $\mathcal{H}^d (E)=0$, then $\mathcal{H}^{d'} (fE)=0$. This conjecture was known to be true if $d'=0$ (obvious), $d'=2$ (Ahlfors), and $d'=1$ (Astala, Clop, Mateu, Orobitg and UT, Duke 2008.) The approach in the last mentioned paper does not generalize to other dimensions. UT showed that Astala's conjecture is sharp in the class of all Hausdorff gauge functions (IMRN, 2008). Lacey, Sawyer and UT jointly proved completely Astala's conjecture in all dimensions (Acta, 2009?) The proof uses Astala's 1994 approach, geometric measure theory, and new weighted norm inequalities for Calder\'{o}n-Zygmund singular integral operators which cannot be deduced from the classical Muckenhoupt $A_p$ theory. These results are intimately related to removability problems for various classes of quasiregular maps. I will particularly mention sharp removability results for bounded $K$-quasiregular maps recently obtained in joint work of Tolsa and UT. The talk will be self-contained. |
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PACM Colloquium |
Topic: |
Testable New Theory about Early-Universe Density Fluctuations and Origins of Solar Systems: Applied-Probability and Quantum-Physics Aspects |
Presenter: |
Erik Vanmarcke, Civil and Environmental Engineering |
Date: |
Monday, November 16, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
Abstract: |
The talk will summarize, with a focus on applied-probability aspects, the main findings, testable predictions and research opportunities stemming from a new probabilistic model of how complex patterns of energy-density fluctuations may have arisen during the inflation phase of the Big Bang. Based on first (quantum-physical) principles and requiring a minimum number of (observationally-accessible) parameters, the "embryonic inflation model" yields a coherent set of testable (hence falsifiable) hypotheses about the formation, evolution, composition, internal structure and cosmic environment of galaxies, stars and planets, and is consistent with key findings from observations of the Cosmic Microwave Background (CMB). Implying a robust alternative (and challenge) to the dual paradigm of spatially-uniform light-element primordial nucleosynthesis and stellar "recycling" of matter as the sole mechanism of heavy-element production, the theory holds the promise of integrating astrophysical and planetary sciences with cosmology and galaxy formation in a coherent evolutionary framework. Observations indicating overall cosmic flatness, the existence of an accelerating component, dark matter and dark energy all fit, in quantifiable and testable ways, into the framework of the theory. |
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Geometry, Representation Theory, and Moduli Seminar |
Topic: |
TBA |
Presenter: |
Z. Yun, IAS |
Date: |
Monday, November 16, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
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Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Paul Hacking, University of Massachusetts Amherst |
Date: |
Tuesday, November 17, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
TBA |
Presenter: |
Lai-Sang Young, Courant Institute |
Date: |
Thursday, November 19, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
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Discrete Mathematics Seminar |
Topic: |
TBA |
Presenter: |
Peter Winkler, Dartmouth College |
Date: |
Thursday, November 19, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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PACM Colloquium |
Topic: |
TBA |
Presenter: |
Warren Powell, ORFE |
Date: |
Monday, November 23, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
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Geometry, Representation Theory, and Moduli Seminar |
Topic: |
TBA |
Presenter: |
D. Zakharov, Columbia University |
Date: |
Monday, November 23, 2009, Time: 4:30 p.m., Location: Fine Hall 314 |
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Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Tommase deFernex, University of Utah |
Date: |
Tuesday, November 24, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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PACM Colloquium |
Topic: |
TBA |
Presenter: |
Joris Dik, Delft University of Technology, Netherlands |
Date: |
Monday, November 30, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
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DECEMBER 2009 |
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Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Ekaterina Amerik, IAS |
Date: |
Tuesday, December 1, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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Discrete Mathematics Seminar *** Please note special day |
Topic: |
TBA |
Presenter: |
Maria Chudnovsky, Columbia University |
Date: |
Wednesday, December 2, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
Unbiased Random Perturbations of Navier-Stokes Equation |
Presenter: |
Boris Rozovsky, Lefschetz Center for Dynamical Systems, Brown University |
Date: |
Thursday, December 3, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
Abstract: |
A random perturbation of a deterministic Navier-Stokes equation is considered in the form of an Stochastic PDE with Wick product in the nonlinear term. The equation is solved in the space of generalized stochastic processes using the Cameron-Martin version of the Wiener chaos expansion. The generalized solution is obtained as an inverse of solutions to corresponding quantized equations.
An interesting feature of this type of perturbation is that it preserves the mean dynam- ics: the expectation of the solution of the perturbed equation solves the underlying deterministic Navier-Stokes equation. From the stand point of a statistician it means that the perturbed model is unbiased. The talk is based on a joint work with R. Mikulevicius. |
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Differential Geometry and Geometric Analysis Seminar |
Topic: |
TBA |
Presenter: |
Christine Breiner, MIT |
Date: |
Friday, December 4, 2009, Time: 3:00 p.m., Location: Fine Hall 314 |
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PACM Colloquium |
Topic: |
Imaging Techniques and the Rejuvenation of Artwork |
Presenter: |
Roy S. Berns, Munsell Color Science Laboratory, Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, USA |
Date: |
Monday, December 7, 2009, Time: 4:00 p.m., Location: Fine Hall 214 |
Abstract: |
Advances in digital imaging within the visible spectrum enable the accurate color rendering of artwork. It is possible to generate a colorimetric image with high spatial resolution and high image quality (appropriate sharpness and low noise). When the number of sensor channels exceeds three, it is also possible to generate spectral images. Spectral images can be used to calculate colorimetric images for any illuminant and observer pair, to evaluate color inconstancy, as an aid in retouching (i.e., restorative inpainting), for pigment mapping, and to improve printed reproductions. These digital images, of course, record the color and spectra of the artwork in its current condition. Depending on how the artwork has aged, its color may bear little resemblance to its appearance when first executed. This can dramatically affect the analysis of the painting in terms of its historical context and understanding the artist's working methods. A variety of techniques can be used to determine such color changes including analysing cross-sections, finding protected areas and identical materials that retain their color, early photographic records, and descriptions by art critics and connoisseurs at the time of creation. Having determined that a color change has occurred, it is possible to rejuvenate the colors of a digital image by using the principles of instrumental-based color matching. These principles are used to determine pigments and their concentrations that when mixed, match a particular color. This is equivalent to pigment mapping. The digital rejuvenation is performed by either replacing the spectral properties of the changed pigment with one that hasn't changed or increasing the concentration of a pigment that has faded. These rejuvenated images, while speculative, provide important and interesting new insights. This presentation will review research by the author in digital rejuvenation using examples by Vincent Van Gogh and Georges Seurat. |
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Algebraic Geometry Seminar |
Topic: |
TBA |
Presenter: |
Roya Beheshti Zavareh, Washington University in St. Louis |
Date: |
Tuesday, December 8, 2009, Time: 4:30 p.m., Location: Fine Hall 322 |
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Ergodic Theory and Statistical Mechanics Seminar |
Topic: |
TBA |
Presenter: |
Michael Boshernitzan, Rice University |
Date: |
Thursday, December 10, 2009, Time: 2:00 p.m., Location: Fine Hall 401 |
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Differential Geometry and Geometric Analysis Seminar |
Topic: |
TBA |
Presenter: |
Song Sun, Wisconsin |
Date: |
Friday, December 11, 2009, Time: 3:00 p.m., Location: Fine Hall 314 |
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Discrete Mathematics Seminar |
Topic: |
TBA |
Presenter: |
Alexandra Ovetsky Fradkin, Princeton University |
Date: |
Thursday, December 17, 2009, Time: 2:15 p.m., Location: Fine Hall 224 |
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