• 2020 Jan 19

    Kazhdan Sunday seminar: Elon Lindenstrauss "Arithmetic applications of diagonal flows"

    Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.
    11:00am to 1:00pm


    Ross 70
    Elon Lindenstrauss "Arithmetic applications of diagonal flows"
    I will give an introduction to the dynamics of higher rank diagonal flows on homogeneous spaces,
    including both the rigidity theorems of such flows and their applications to orbits of arithmetic interest,
    in particular CM points and integer points on spheres.
    I hope to cover parts of the following papers:
    Einsiedler, Manfred ; Lindenstrauss, Elon ; Michel, Philippe ; Venkatesh, Akshay . The distribution of closed geodesics
  • 2020 Jan 19

    Kazhdan Sunday seminar: "Computation, quantumness, symplectic geometry, and information" (Gil Kalai, Leonid Polterovich, with participation of Dorit Aharonov and Guy Kindler)

    Repeats every week every Sunday until Sat Feb 01 2020 except Sun Dec 29 2019.
    2:00pm to 4:00pm


    Ross 70

    Tentative syllabus
    1. Mathematical models of classical and quantum mechanics.
    2. Correspondence principle and quantization.
    3. Classical and quantum computation: gates, circuits, algorithms
    (Shor, Grover). Solovay-Kitaev. Some ideas of cryptography
    4. Quantum noise and measurement, and rigidity of the Poisson bracket.
    5. Noisy classical and quantum computing and error correction, threshold theorem- quantum fault tolerance (small noise is good for quantum computation). Kitaev's surface code.
  • 2020 Jan 19

    Game theory seminar: Computational Design Principles of Cognition (Yuval Hart)

    2:00pm to 3:00pm


    Elath Hall, 2nd floor, Feldman Building
    Driven by recent technological advancements, behavior and brain activity can now be measured at an unprecedented resolution and scale. This “big-data” revolution is akin to a similar revolution in biology. In biology, the wealth of data allowed systems-biologists to uncover the underlying design principles that are shared among biological systems. In my studies, I apply design principles from systems-biology to cognitive phenomena. In my talk I will demonstrate this approach in regard to creative search.
  • 2020 Jan 19

    Kazhdan Sunday seminar: Tomer Schlank "Prismatic cohomology" (after Bhatt and Scholze)

    Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.
    4:00pm to 6:00pm


    Ross 70
    Tomer Schlank "Prismatic cohomology" (after Bhatt and Scholze)
    Abstract: We shall discuss (Weil) cohomology theories for algebraic varieties.
    When working with schemes over p-complete rings and taking cohomologies with p-complete coefficients one gets a plurality of such cohomology theories (e'tale, De-Rahm, Crystalline, etc.. ). The comparison between these different cohomology theories is a subtle subject known as "p-adic hodge theory" .
  • 2020 Jan 21

    Sebastian Barbieri (Bordeaux) On the relation between topological entropy and asymptotic pairs

    2:00pm to 3:00pm

    Abstract: I will present some results that state that under certain
    topological conditions, any action of a countable amenable group with
    positive topological entropy admits off-diagonal asymptotic pairs. I
    shall explain the latest results on this topic and present a new
    approach, inspired from thermodynamical formalism and developed in
    collaboration with Felipe García-Ramos and Hanfeng Li, which unifies all
    previous results and yields new classes of algebraic actions for which
  • 2020 Jan 23

    Groups & Dynamics Seminar. Chloe Perin (HUJI): Homogeneity of torsion-free hyperbolic groups

    10:00am to 11:00am


    Ross 70 a
    A countable group is said to be homogeneous if whenever tuples of elements u, v satisfy the same first-order formulas there is an automorphism of the group sending one to the other. We had previously proved with Rizos Sklinos that free groups are homogeneous, while most surface groups aren't. In a joint work with Ayala Dente-Byron, we extend this to give a complete characterization of torsion-free hyperbolic groups that are homogeneous.
  • 2020 Jan 23

    Colloquium: Gil Kalai (HUJI) - Some recent advances in combinatorics

    2:30pm to 3:30pm


    Manchester Building (Hall 2), Hebrew University Jerusalem
    I will discuss some recent advances in combinatorics, among them the disproof of Hedetniemi conjecture by Shitov, the proof of the sensitivity conjecture by Huang, the progress on the Erdos-Rado sunflower conjecture by Alweiss, Lovett, Wu, and Zhang, and the progress on the expectation threshold conjecture by Frankston, Kahn, Narayanan, and Park.