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GT Seminar                                                                  (in collaboration with Frontiers in Math. Sci.)
Speaker: 
Farhad Babaee
Ecole Normale Supérieure, Paris
Title: 
A tropical approach to the strongly positive Hodge conjecture
Abstract: 
I will briefly explain complex tropical currents, and will address their extremality, intersection theory, and approximation problems. I will discuss how in joint work with June Huh, we constructed an example of a non-approximable tropical current, which, in turn, refutes a stronger version of the Hodge conjecture.
Date: Thursday Dec 31, 2015
Time: 14:00-16:00
Location: Lecture Hall 1,
Niavaran Building, IPM


5th Meeting on Contemporary Mathematics
School of Mathematics, IPM
December 27-28, 2015
Speaker: 
Mihalis Dafermos
University of Cambridge & Princeton University
Title: 
The geometry and analysis of black holes spacetimes in general relativity
Date
&
Time: 		Sunday, December 27, 2015
  • 14:00-15:00,  1st Lecture
  • 15:30-16:30,  2nd Lecture

    • Monday, December 28, 2015
  • 14:00-15:00,  3rd Lecture
  • 15:30-16:30,  4th Lecture

    		•
    Location: Farmanieh Lecture Hall, IPM,
    Lavasani Street, Tehran.          →  Map
    Registration: The attendance is free, but requires registration.
    Please fill out the registration form and
    send it to gt@ipm.ir with the subject "MCM".
    		Poster

    Seminar                                                                      (in collaboration with Frontiers in Math. Sci.)
    Speaker: 
    		Sam Nariman
    Stanford University
    Title: 
    		On the moduli space of flat surface bundles
    Abstract: 
    		Flat manifold bundles (i.e. manifold bundles with foliations transverse to the fibers) are classified by homotopy classes of maps to the classifying space of diffeomorphisms made discrete. In this talk, I will talk about homological stability of discrete surface diffeomorphisms and discrete symplectic diffeomorphisms which was conjectured by Morita. I will describe an infinite loop space related to the Haefliger space whose homology is the same as group homology of discrete surface diffeomorphisms in the stable range. Finally, I will discuss some interesting applications to the characteristic classes of flat surface bundles and foliated bordism groups of codimension 2 foliations.
    Date: Thursday, December 24, 2015
    Time: 15:30-17:00
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    Seminar                                                                      (in collaboration with Frontiers in Math. Sci.)
    Speaker: 
    		Sam Nariman
    Stanford University
    Title: 
    		Mumford's conjecture from topological point of view
    Abstract: 
    		In this talk, we will give an expository account of steps of a proof of the Mumford conjecture. In 1983 Mumford conjectured that the cohomology of the moduli space of curves with rational coefficients is a polynomial ring in a certain cohomological degrees. The first proof by Madsen and Weiss was a tour de force. Since then the arguments have been significantly simplified. We will sketch the steps of the simplified proof.
    Date: Wednesday, December 23, 2015
    Time: 15:30-17:00
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    Seminar
    Speaker: 
    		Sadok Kallel
    Universite de Lille 1 & American University of Sharjah
    Title: 
    		Homological Splitting Techniques in Algebraic Topology
    Abstract: 
    		A space is said to split stably if after "suspension" it breaks down into the one-point union of simpler spaces. It is said to split homologically if it has the homology of such a union. Splitting a space X can be greatly useful in getting information about X or in comparing it to other spaces. In this talk we describe general methods to split filtered spaces stably and homologically in terms of the pieces of the filtration. This expands on works of Stylian Zanos and Fred Cohen. Examples and applications to geometry will be presented.
    Date: Saturday, December 5, 2015
    Time: 9:30-11:00
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    Seminar
    Speaker: 
    		Sadok Kallel
    Universite de Lille 1 & American University of Sharjah
    Title: 
    		An Introduction to Configuration Spaces and some of their Applications
    Abstract: 
    		We discuss some foundational results on the topology and geometry of configuration spaces of ordered and unordered pairwise distinct points on a topological space, most particularly on a manifold. We illustrate some of the nicest ideas in the theory with basic examples and homology computations. Various classical applications will be reviewed. Finally if time permits, we explain how configuration spaces and labeled analogs can be used to model mapping spaces of continuous and rational maps. This leads to effective homological computations for both based and free loop spaces.
    Date: Tuesday, December 1, 2015
    Time: 14:00-15:30
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    GT Seminar (Special Talk)
    Speaker: 
    		Thierry Monteil
    Centre National de la Recherche Scientifique (CNRS)
    Title: 
    		Finite blocking property and illumination on polygonal billiards and translation surfaces
    Abstract: 
    		A planar polygonal billiard $P$ is said to have the finite blocking property if for every pair $(O,A)$ of points in $P$ there exists a finite number of "blocking" points $B_1,‎\ldots‎,B_n$ such that every trajectory from $O$ to $A$ meets one of the $B_i$'s.

    This property was introduced in a problem of the Leningrad's Olympiad in 1989, and solved there for the squared billiard table (we will see that the square has the finite blocking property). The talk will focus on this property, that can be considered as a property about illumination in $P$. We will first introduce the basic notion of a translation surface that allows to study rational polygonal billiards.

    The complete characterization relies on recent results of Alex Eskin, Maryam Mirzakhani, and Amir Mohammadi, which gives strong information about the dynamics of $SL(2,‎\mathbb{R}‎)$ on the moduli space of translation surfaces.

    With similar techniques, we might also show that, for any translation surface, each point illuminates all the surface, but at most finitely many points.
    Date: Wednesday, September 9, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    Short Course
    Speaker: 
    		Majid Narimannejad
    Visiting Fellow (European Research Grant)
    Title: 
    		TQFT and Geometry
    Abstract: 
    In the late 1980, in his seminal work, E. Witten introduced new invariants of 3-manifolds, by quantizing Chern-Simons quantum field theory and proposed a (formal) 3-dimensional interpretation of Jones polynomial. ... more info.

    In a series of 4 lectures we will try to give an introduction to this subject and also present some ongoing projects and questions.

    Date: Monday, May 25, 2015
    Tuesday, May 26, 2015
    Sunday, June 14, 2015
    Tuesday, June 16, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 1,
    Niavaran Building, IPM



    3rd Workshop in Dynamical Systems
    School of Mathematics, IPM
    June 6-8, 2015
    Program:

    		9:30 -
      10:10    		 10:15 -
      10:55    		 11:00 -
      11:30    		 11:30 -
      12:30    		 12:30 -
      14:00    		 14:00 -
      14:40    		 14:45 -
      15:25    		 15:30 -
      16:00    		 16:00 -
      17:00
    Saturday Ghiasi Rajabzadeh Tea Zaj Lunch Abbasi Fadaee Tea Discussion
    Sunday Attarzadeh Azimi Tea Makrooni Lunch Discussion Discussion Tea Discussion
    Monday Rashid Talebi Tea Tavakoli

    More info at http://math.ipm.ir/gt/WDS3.html
    Registration: 
    		The attendance is free, but requires registration.
    Please fill out the registration form and send it to gt@ipm.ir with the subject  WDS3.
    Deadline: May 31, 2015 (دهم خرداد)
    Location:       Lecture Hall 1,
    Niavaran Building, IPM


    GT Seminar
    Speaker: 
    		Asghar Ghorbanpour
    University of Western Ontario
    Title: 
    		The Curvature of the Determinant Line Bundle for the Noncommutative Two Torus
    Abstract: 
    		Following Quillen's original construction of the determinant line bundle for Riemann surfaces and using zeta regularized determinant of Laplacians, one can endow the determinant line bundle with a natural Hermitian metric and compute its curvature.

    I will show how we (in the joint work with  M. Khalkhali and A. Fathi [arXiv:1410.0475]) computed the curvature of the determinant line bundle for a family of Dirac operators for the noncommutative two tori. To study the geometry of the determinant line bundle, the canonical trace of Kontsevich-Vishik is developed  for the  algebra of pseudodifferential operators on the  noncommutative two torus. Using the  calculus of symbols and the canonical trace  we computed the curvature of the determinant line bundle, which is the second variation of $\log\det(\Delta)$.
    Date: Sunday, June 7, 2015
    Time: 14:00-15:30
    Location: Lecture Hall 1,
    Niavaran Building, IPM


    GT Seminar
    Speaker: 
    		Mahdi Khajeh Salehani
    University of Tehran
    Title: 
    		Classical nonholonomic vs. vakonomic mechanics: a geometric report on the 'debate'
    Abstract: 
    To study constrained mechanical systems, there are at least two approaches one may take, namely the "classical nonholonomic approach", which is based on the Lagrange-d'Alembert principle and is not variational in nature, and a variational axiomatic one known as the "vakonomic approach".

    In fact there are some fascinating differences between these two procedures, e.g., they do not always give the same equations of motion; the distinction between these two procedures has a long and distinguished history going back to Korteweg (1899), and has been discussed in a more modern context by Arnold, Kozlov and Neishtadt since 1983.

    In this seminar, we present the classical nonholonomic mechanics and the vakonomic mechanics of systems with constraints, and will compare them in order to see when these two mechanics are equivalent, i.e., when they give the same system of equations. For the class of mechanical systems that they are not so, we determine which one of these approaches is the appropriate one for deriving the equations of (mechanically possible) motions.

    Date: Thursday, May 28, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 2,
    Niavaran Building, IPM


    GT Seminar
    Speaker: 
    		Abbas Fakhari
    Shahid Beheshti University & IPM
    Title: 
    		IFS: Lebesgue measure vs. stationary measure
    Abstract: 
    In this talk we discus the difference between the Lebesgue measure and stationary measure arisen by a semi-group action. We talk a bit more about the minimal IFSs, their unique stationary measure and Erdős problem in this context.
    Date: Thursday, May 14, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 2,
    Niavaran Building, IPM


    4th Meeting on Contemporary Mathematics
    School of Mathematics, IPM
    May 10, 2015
    Speaker: 
    		Cédric Villani
    Université de Lyon & Institut Henri Poincaré
    Title: 
    		Synthetic theory of Ricci curvature, when Monge meets Riemann
    Date: 
    		Sunday, May 10, 2015
    Time: 
    		 10:45-12:00,  1st Lecture
    14:00-15:00,  2nd Lecture
    15:30-16:30,  3rd Lecture
    Location: Farmanieh Lecture Hall, IPM,
    Lavasani Street, Tehran.            →  Map
    		Poster

    GT Seminar
    Speaker: 
    		Meysam Nassiri
    School of Mathematics, IPM
    Title: 
    		Topological methods in low dimensional dynamics
    Abstract: 
    		I will talk about the dynamics of a surface homeomorphism restricted to the boundary of an invariant domain. In the area-preserving setting, we give a classification of the dynamics which is very similar to Poincaré's theory for circle homeomorphisms.
    I will also discuss some of the consequences of this result.
    The talk is based on a joint work with Andres Koropecki and Patrice Le Calvez.
    Date: Thursday, May 7, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 2,
    Niavaran Building, IPM


    GT Seminar
    Speaker: 
    		Mohammad Safdari
    School of Mathematics, IPM
    Title: 
    		Variational inequalities with gradient constraints
    Abstract: 
    In this talk, we consider the problem of minimizing a functional subject to a pointwise gradient constraint. We show that this problem is equivalent to a double obstacle problem with nondifferentiable obstacles. Then, we prove the regularity of the solution to our problem, which is better than the expected regularity of a generic double obstacle problem with nondifferentiable obstacles.
    Date: Thursday, April 30, 2015
    Time: 14:00-16:00
    Location: Lecture Hall 2,
    Niavaran Building, IPM


    GT Seminars
    February 19, 2015 - May 14, 2015

    School of Mathematics,
    IPM - Institute for Research in Fundamental Sciences
    Niavaran Building, Niavaran Square, Tehran, Iran
    Tel: +98 21 222 90 928
    		 Email: gt@ipm.ir