Colloquium

  • 2019 May 02

    Colloquium: Jake Solomon- Pointwise mirror symmetry

    2:30pm to 3:30pm

    Location: 

    Manchester Building (Hall 2), Hebrew University Jerusalem

    Abstract: Mirror symmetry is a correspondence between symplectic geometry on a manifold M and complex geometry on a mirror manifold W. The question of why one sort of geometry on M should be reflected in another sort of geometry on the topologically distinct manifold W, and the question of how to find W given M, are a priori highly mysterious. One attempt to explain the mysteries of mirror symmetry is the SYZ conjecture, which asserts that the mirror manifold W can be realized as the moduli space of certain objects of a category associated to M.
  • 2019 Apr 11

    Colloquium: Ohad Feldheim - Lattice models of magnetism: from magnets to antiferromagnets

    2:30pm to 3:30pm

    Location: 

    Manchester Building (Hall 2), Hebrew University Jerusalem

    Abstract:
    The Ising model, and its generalisation, the Potts model, are two classical graph-colouring models for magnetism and antiferromagnetism. Albeit their simple formulation, these models were instrumental in explaining many real-world magnetic phenomena and have found various applications in physics, biology and computer science. While our understanding of these models as modeling magnets has been constantly improving since the early twentieth century, little progress was made in treatment of Potts antiferromagnets.
  • 2019 Apr 04

    Colloquium: Uri Shapira (Technion) - Dynamics on hybrid homogeneous spaces

    2:30pm to 3:30pm

    Location: 

    Manchester Building (Hall 2), Hebrew University Jerusalem
    Abstract: I will discuss a collection of results about lattices and their subgroups in Euclidean space which are obtained using dynamics on homogeneous spaces. The ergodic theory of group actions on spaces obtained by quotienning a Lie group by a lattice (spaces of lattice-type) or on projective spaces are extensively studied and display distinct dynamical phenomena. Motivated by classical questions in Diophantine approximation we are led to study the ergodic theory of group actions on hybrid homogeneous spaces which are half projective and half of lattice type.
  • 2019 Mar 14

    Colloquium: Alexander Bors (University of Western Australia) - Finite groups with a large automorphism orbit

    2:30pm to 3:30pm

    Location: 

    Manchester Building (Hall 2), Hebrew University Jerusalem
    Abstract: If X is an object such that the notion of an automorphism of X is defined (e.g.,
    an algebraic structure, a graph, a topological space, etc.), then one can define an
    equivalence relation ∼ on X via x ∼ y if and only if α(x) = y for some automorphism
    α of X. The equivalence classes of ∼ are called the automorphism orbits of X.
    Say that X is highly symmetric if and only if all elements of X lie in the same
    automorphism orbit. Finite highly symmetric objects are studied across various

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