The Mathematics Calendar
http://www.math.psu.edu/seminars/calendar.php
Seminars and special events the Pennsylvania State University Mathematics Department2016-02-13webmaster@math.psu.eduWhat is new for incompressible Euler?
http://www.math.psu.edu/seminars/meeting.php?id=30250
Speaker(s): Dong Li
I will discuss some new exciting developments for
incompressible Euler and related fluid
equations in recent years, with a focus on understanding the solution
operator, wellposedness
issues and (harmonic) analysis perspectives.2016-02-15T12:20:00CCMA Luncheon Seminarxli@math.psu.edusaz11@math.psu.eduliu@math.psu.eduNorm inflation in hydrodynamics
http://www.math.psu.edu/seminars/meeting.php?id=30234
Speaker(s): Dong Li
I will discuss a number of recent results concerning the
norm inflation phenomena of fluid equations in various functional spaces. In
particular I will focus on some new techniques to explore (beyond) the limitation of traditional energy type methods. Time permitting I will also discuss some new developments in related
Kato-Ponce type inequalities and new fractional Leibniz rules. (Part
of the work is joint with Jean Bourgain).2016-02-15T14:30:00Computational and Applied Mathematics Colloquiumxli@math.psu.edusaz11@math.psu.eduliu@math.psu.edufuw7@math.psu.eduPostive loops - on a question by Eliashberg-Polterovich and a contact systolic inequality
http://www.math.psu.edu/seminars/meeting.php?id=30063
Speaker(s): Peter Albers
In 2000 Eliashberg-Polterovich introduced the concept of positivity in contact geometry. The notion of a positive loop of contactomorphisms is central. A question of Eliashberg-Polterovich ist whether C^0-small positive loops exist. We give a negative answer to this question. Moreover we give sharp lower bounds for the size which, in turn, gives rise to a L^\infty-contact systolic inequality. This should be contrasted with a recent result by Abbondandolo et. al. that on the standard contact 3-sphere no L^2-contact systolic inequality exists. The choice of L^2 is motivated by systolic inequalities in Riemannian geometry. This is joint work with U. Fuchs and W. Merry.2016-02-15T15:35:00Dynamical systems seminarkatok_s@math.psu.edusaz11@math.psu.edukatok_a@math.psu.eduhertz@math.psu.eduJordan Groups, Abelian Varieties and Conic Bundles
http://www.math.psu.edu/seminars/meeting.php?id=29253
Speaker(s): Yuri Zarhin
A classical theorem of Jordan asserts that each finite subgroup of the complex general linear group GL(n) is ``almost commutative": it contains a commutative normal subgroup
with index bounded by a universal constant that depends only on n.
We discuss an analogue of this property for the groups of birational (and biregular) automorphisms of complex algebraic varieties and the groups of diffeomorphisms of real manifolds.
This is a report on a joint work with Tatiana Bandman (Bar-Ilan).2016-02-16T14:30:00GAP Seminareus25@math.psu.eduhigson@math.psu.eduping@math.psu.edustienon@math.psu.eduroyer@math.psu.eduFine Structure Theory and Algorithmic Randomness (II)
http://www.math.psu.edu/seminars/meeting.php?id=29285
Speaker(s): Jan Reimann
Jensen's fine structure theory allows for a canonical definition of codes for levels of Goedel's constructible universe similar to how the Turing jump codes levels of the arithmetic hierarchy. In this talk, we will show how Jensen's codes and algorithmic randomness behave mutually orthogonal. This allows us in turn to derive a metamathematical result about randomness with respect to continuous measures.2016-02-16T14:30:00Logic Seminarreimann@math.psu.edusimpson@math.psu.edujmr71@math.psu.eduErgodic theory of C^1 generic conservative diffeomorphisms: II.
http://www.math.psu.edu/seminars/meeting.php?id=30042
Speaker(s): Jairo Bochi
In this pair of talks, I'll survey what is known about the ergodic theory of C^1-generic volume-preserving and symplectic diffeomorphisms, and what are the various perturbation techniques used to prove those results. In the first part, I'll explain a statement of Mañé (generic area-preserving diffeomorphisms either have zero Lyapunov exponents a.e. or are Anosov), and its higher-dimensional generalizations. In the second part, I'll explain more recent results, culminating with the following theorem of Avila, Crovisier, and Wilkinson: C^1-generic volume-preserving diffeomorphisms either have zero Lyapunov exponents a.e. or the volume measure is ergodic, hyperbolic, and moreover the splitting into stable and unstable spaces is globally uniformly dominated.2016-02-16T15:32:00Working Seminar: Dynamics and its Working Toolskatok_a@math.psu.edusaz11@math.psu.edukatok_s@math.psu.eduhertz@math.psu.eduSL(2,R) seminar
http://www.math.psu.edu/seminars/meeting.php?id=31130
Speaker(s): Various
This seminar will example aspects of the representation theory of SL(2,R)2016-02-16T16:15:00Special Eventhigson@math.psu.eduCones of higher codimension cycles
http://www.math.psu.edu/seminars/meeting.php?id=29228
Speaker(s): Izzet Coskun
There is a well-developed theory of effective and nef divisors on projective varieties. In contrast, the theory of higher codimension cycles is much more difficult and we lack good criteria for determining when cycle classes are effective or nef. In this talk, I will discuss joint work with John Lesieutre on higher codimension pseudo-effective cones of blowups of projective space. In particular, we show that for a very general point blowup of projective space which is a Mori Dream Space all higher codimension effective cones are finitely generated. This is false for blowups of projective space along higher dimensional subvarieties. If time permits, I will discuss joint work with Dawei Chen on higher codimension cycles on moduli spaces of curves.2016-02-18T11:15:00Algebra and Number Theory Seminarrvaughan@math.psu.edupapikian@math.psu.eduyee@math.psu.edueisentra@math.psu.eduPositivity in contact geometry
http://www.math.psu.edu/seminars/meeting.php?id=30200
Speaker(s): Peter Albers
The notion of positivity in contact geometry was introduced in 2000 by Eliashberg and Polterovich. For example, geodesic flows (and more generally Reeb flows) are positive. This and other examples will be explained during the talk. Positivity has connections to many phenomena such as contact (non-)squeezing and biinvariant partial orders. Positivity leads to a generalization of the classical Bott-Samelson theorem and has connection to the famous Weinstein conjecture. Examples will be presented throughout the talk.2016-02-18T15:35:00Department of Mathematics Colloquiumsaz11@math.psu.eduliu@math.psu.eduauh243@math.psu.edu