View Year
<>December 2015  




See also the PSU Calendars
Log in to request a room reservation that will appear here for special events. Click on a day to view the room schedule for available times.
Weekly RSS Feed
A live feed of seminars and special events in the upcoming week.
 December 1st, 2015 (11:15am  12:05pm)
 Seminar: Combinatorics/Partitions Seminar
Title: Generalized Frobenius partitions and Jacobi forms
Speaker: Larry Rolen, PSU
Location: MB106In a 1984 memoir, Andrews defined the notion of a generalized Frobenius partition. Since then, many authors have considered explicit formulas and congruences for functions counting these objects. Here, in joint work with Kathrin Bringmann and Mike Woodbury, I will show how interpreting these functions in the context of Jacobi forms and theta decompositions gives a natural interpretation of the counting functions for generalized Frobenius partitions into $k$ colors in terms of character formulas of Kac and Wakimoto, and how the structure of theta decompositions can be used to give inductive formulas for the generating functions.
 December 1st, 2015 (01:30pm  02:20pm)
 Seminar: Theoretical Biology Seminar
Title: Modeling HIV latency reversing agents and its implications for clinical trial design
Speaker: Ruian Ke, North Carolina State University
(Host: Jessica Conway)
Location: MB106A major barrier to cure HIV infection is the existence of a population of long lived latently infected cells, i.e. the HIV latent reservoir. Recent efforts have focused on developing latency reversing agents (LRAs) to activate HIV expression in latently infected cells in order to purge the HIV latent reservoir. However, it is not clear to what extent LRAs impact the latency reversing process and which steps in the process determine the rate of reservoir reduction. Furthermore, accurately measuring the size of the reservoir experimentally has been challenging. All these issues make evaluating the efficacy of candidate LRAs and predicting treatment outcomes difficult. To address these issues, we developed a series of mathematical models to describe the dynamics of latently infected cells under LRA treatment. In the first part of the talk, I will present our work on understanding the impact of one of the first LRAs, vorinostat. By fitting viral dynamic models to clinical data, we show that vorinostat induces both transient and delayed HIV transcriptional activation in vivo . However, killing of latently infected cells in treated patients is minimal. In the second part of the talk, I will discuss a stochastic model that incorporates both HIV activation process in vivo and clinical sampling procedures in a probabilistic framework. We identify key parameters that determine the rate of latent reservoir reduction, and using information theory, we evaluate the accuracy in estimating these parameters using data collected from three commonly used experimental assays. To conclude, this framework provides a useful tool for designing future clinical trials and experiments to evaluate the efficacy of candidate LRAs and predict longterm treatment outcomes.
 December 1st, 2015 (02:30pm  03:30pm)
 Seminar: GAP Seminar
Title: Algebraic Families of HarishChandra pairs and their modules II
Speaker: Eyal Subag, Penn State
Location: MB106In my talk I will try to convince you that Lie groups come in natural algebraic families. A construction of such families that relates different real forms of GL(n,C), and SL(n,C) will be given. Moreover, we shall see that we can naturally associate families of HarishChandra pairs to these families of groups. For the family that goes through SU(2), SU(1,1), and their Cartan motion group, a classification of generically irreducible Harish Chandra modules will be given. As an application, a formulation of the Mackey bijection between the duals of SU(1,1) and its Cartan motion group in terms of families of Harish Chandra modules will be presented. The talk is based on a joint work with Joseph Bernstein and Nigel Higson.
 December 1st, 2015 (02:30pm  03:45pm)
 Seminar: Logic Seminar
Title: Hausdorff Dimension, Irrationality Exponents and Their Effectivization
Speaker: Jan Reimann, Penn State
Location: MB315We generalize the classical theorem by Jarnik and Besicovitch on the irrationality exponents of real numbers and Hausdorff dimension. Let a be any real number greater than or equal to 2 and let b be any nonnegative real less than or equal to 2/a. We show that there is a Cantorlike set with Hausdorff dimension equal to b such that, with respect to its uniform measure, almost all real numbers have irrationality exponent equal to a. We give an analogous result relating the irrationality exponent and the Hausdorff dimension of individual real numbers. We prove that there is a Cantorlike set such that, with respect to its uniform measure, almost all reals in the set have effective Hausdorff dimension equal to b and irrationality exponent equal to a. This is joint work with V. Becher and T. Slaman.
 December 1st, 2015 (02:30pm  03:29pm)
 Seminar: Center for Dynamics and Geometry Colloquium
Title: Non hyperbolic dynamics and nonhyperbolic measures.
Speaker: Christian Bonatti, University of Dijon
Location: MB114Hyperbolicity provides a simple understanding of chaotic dynamics. In some sense, hyperbolic dynamics are the most complicated dynamics for which one can give a complete topological description. An even more precise description of the dynamics of hyperbolic systems can be obtained through ergodic theory. However, hyperbolic systems are far from being all chaotic systems: there are numerous robustly nonhyperbolic systems. I will review several results and mechanisms showing that the existence of nonhyperbolic measures can be robust. In fact, the robust existence of non hyperbolic measure may be the most common situation in the nonhyperbolic world. I will review several results and mechanisms showing that the existence of nonhyperbolic measures can be robust. In fact, the robust existence of non hyperbolic measure may be the most common situation in the nonhyperbolic world.
 December 1st, 2015 (03:30pm  06:00pm)
 Seminar: Working Seminar: Dynamics and its Working Tools
Title: Partially hyperbolic diffeomorphisms of 3 manifolds I. ATTENTION: THIS TALK WILL START AT 3:45pm
Speaker: Christian Bonatti, University of Dijon
Location: MB114For decades, the only known examples of partially hyperbolic diffeoomorphisms on 3manifolds were "centerleaf conjugated", up to taking lift to finite covers and finite powers, to three simple models:  time one map of Anosov flows  Anosov diffeomorphisms on T3 with 3 real distinct eigenvalues  a skew product of an Anosov diffeomorphism of T2 by circle diffeomorphism. Recently many new examples appear, still very related with the models but not isotopic to them:  (non transitive) partially hyperbolic diffeomorphisms on T3 whose center bundle is robustly not tangent to any foliation.  (transitive and not transitive) partially hyperbolic diffeomorphisms on manifolds supporting an Anosov flow, which are not isotopic to identity. I will present these new examples. The first of them is already written and it opened the door to building many more: I will also present many examples that are still work in progress.
 December 2nd, 2015 (12:00pm  01:30pm)
 Seminar: Geometry Luncheon Seminar
Title: TBA
Speaker: Carina Curto, Penn State
Location: MB114  December 3rd, 2015 (02:30pm  03:30pm)
 Seminar: Noncommutative Geometry Seminar
Title: Convolution algebras and group representations I
Speaker: Nigel Higson, PSU
Location: MB106  December 3rd, 2015 (03:35pm  04:25pm)
 Seminar: Department of Mathematics Colloquium
Title: Faculty Meeting
Speaker: Faculty Meeting
Location: MB114  December 7th, 2015 (03:35pm  04:35pm)
 Seminar: Dynamical systems seminar
Title: Flexibility of topological and metric entropies for surfaces of negative curvature.
Speaker: Alena Erchenko, Penn State
Location: MB114We consider a smooth closed surface $M$ of fixed genus $\geqslant 2$ and fixed volume with a Riemannian metric $g$ of negative curvature. A. Katok has shown that the topological entropy of geodesic flow for $g$ is greater than or equal to the topological entropy for the metric of constant negative curvature on $M$ which is greater than or equal to the metric entropy with respect to the Liouville measure of geodesic flow for $g$. Equality holds only in the case of constant negative curvature. It turns out that this is the only restriction on pairs of values of topological and metric entropies. We will discuss several examples with particular distributions of curvature.
 December 8th, 2015 (01:30pm  02:20pm)
 Seminar: Theoretical Biology Seminar
Title: Intraindividual evolution of the T cell repertoire
Speaker: Philip Johnson, University of Maryland, College Park
(Host: Jessica Conway)
Location: MB106The vertebrate T cell adaptive immune response has the challenging task of recognizing any possible pathogen while never attacking "self." Evolution's solution to this challenge has been to generate a repertoire of T cells within a single individual via a process of recombination and intraindividual selection that creates a vast diversity of distinct T cell receptors (TCRs). High throughput sequencing enables serial, deep sampling of this repertoire and thus allows us to address long standing questions regarding how the repertoire is formed and shaped over the lifetime of the individual. These data have required the development of methods to account for sequencing error in pooled samples of mixed frequencies and to account for variation among biological replicates. I will present these methods along with data from experimental collaborators as I investigate the question of "Why do we see public T cell responses with the the same TCRs in different individuals?"
 December 8th, 2015 (02:30pm  03:30pm)
 Seminar: GAP Seminar
Title: TBA
Speaker: Zvi Rosen, Penn State
Location: MB106  December 8th, 2015 (02:30pm  03:45pm)
 Seminar: Logic Seminar
Title: Triviality and lowness for Kreducibility and related reducibilities
Speaker: William C. Calhoun, Bloomsburg University
Location: MB315A set of natural numbers A is Ktrivial if K(An) <= K(n)+O(1) for all natural numbers n (where An is A restricted to n and K is prefixfree Kolmogorov complexity). The set A is low for K if K^{A}(y)=K(y)+O(1) for all binary strings y. These definitions seem quite different. Ktriviality indicates that initial segments of A have the lowest possible complexity, while lowness for K indicates that A is too weak as an oracle to reduce the complexity of any string. The remarkable equivalence of the two definitions was shown in [2]. Replacing prefixfree complexity by monotone complexity in the definition of Ktrivial, we obtain the Kmtrivial sets. Every Ktrivial set is Kmtrivial and all Turing degrees >= 0' contain a Kmtrivial set [1]. Yet, not every Turing degree contains a Kmtrivial set. We obtain a superset of the Kmtrivial sets by defining A to be almost trivial if there is a real number a such that K(An) <= aK(n) +O(1). Every Kmtrivial set is almost trivial. However, the Turing degree of a computably dominated MLrandom cannot contain any almost trivial set. An interesting question is to determine which Turing degrees contain Kmtrivial sets (or almost trivial sets). Recently, this question has been considered for minimal Turing degrees. We also consider lowness for monotone and a priory complexity.
[1] Calhoun, W.C.: Triviality and minimality in the degrees of monotone complexity, Journal of Logic and Computation 22, 197206 (2012).
[2] Nies, Andre: Lowness properties and randomness, Advances in Mathematics 197, 274305 (2005).
 December 8th, 2015 (03:30pm  06:00pm)
 Seminar: Working Seminar: Dynamics and its Working Tools
Title: Partially hyperbolic diffeomorphisms of 3 manifolds. II
Speaker: Christian Bonatti, University of Dijon
Location: MB114For decades, the only known examples of partially hyperbolic diffeoomorphisms on 3manifolds were "centerleaf conjugated", up to taking lift to finite covers and finite powers, to three simple models:  time one map of Anosov flows  Anosov diffeomorphisms on T3 with 3 real distinct eigenvalues  a skew product of an Anosov diffeomorphism of T2 by circle diffeomorphism. Recently many new examples appear, still very related with the models but not isotopic to them:  (non transitive) partially hyperbolic diffeomorphisms on T3 whose center bundle is robustly not tangent to any foliation.  (transitive and not transitive) partially hyperbolic diffeomorphisms on manifolds supporting an Anosov flow, which are not isotopic to identity. I will present these new examples. The first of them is already written and it opened the door to building many more: I will also present many examples that are still work in progress.
 December 9th, 2015 (12:00pm  01:30pm)
 Seminar: Geometry Luncheon Seminar
Title: TBA
Speaker: Jeffrey Case, Penn State
Location: MB114  December 10th, 2015 (10:30am  05:00pm)
 Seminar: Department of Mathematics Colloquium
Title: Staff Appreciation Tea
Speaker: Staff Appreciation Tea
Location: MB114  December 10th, 2015 (11:15am  12:05pm)
 Seminar: Algebra and Number Theory Seminar
Title: Algebra and Number Theory Seminar
Speaker: Will be on Friday, 11:15, room MB114, None
Location: MB106Valentin Blomer will speak on Friday
 December 10th, 2015 (02:30pm  03:30pm)
 Seminar: Noncommutative Geometry Seminar
Title: Convolution algebras and group representations II
Speaker: Nigel Higson, PSU
Location: MB106  December 10th, 2015 (05:10pm  07:10pm)
 Seminar: Ph.D. Oral Comprehensive Examination
Title: "Thermodynamics of some nonuniformly hyperbolic attractors"
Speaker: Agnieszka ZelerowiczAdviser, Yakov Pesin, Penn State
Location: MB106  December 11th, 2015 (11:15am  12:05pm)
 Seminar: Algebra and Number Theory Seminar
Title: On a certain senary cubic form
Speaker: Valentin Blomer, Institute for Advanced Study and University of Goettingen
Location: MB114We establish an asymptotic formula (with power saving error term) for the number of rational points of bounded height for a certain cubic fourfold, thereby proving a strong form of Manin's conjecture for this case by a variety techniques from analytic number theory, combinatorics and arithmetic geometry.
 December 15th, 2015 (02:30pm  03:30pm)
 Seminar: GAP Seminar
Title: Localization and the canonical commutation relations
Speaker: Patrick Moylan, Penn State
Location: MB106
Abstract: http://www.personal.psu.edu/ndh2/MoylanGapAbstract.pdf