Ross building, Hebrew University of Jerusalem, (Room 70)
To every topological group, one can associate a unique universal
minimal flow (UMF): a flow that maps onto every minimal flow of the
group. For some groups (for example, the locally compact ones), this
flow is not metrizable and does not admit a concrete description.
However, for many "large" Polish groups, the UMF is metrizable, can be
computed, and carries interesting combinatorial information. The talk
will concentrate on some new results that give a characterization of
metrizable UMFs of Polish groups. It is based on two papers, one joint
The (wrapped) Fukaya category of a symplectic manifold is a category whose objects are Lagrangian submanifolds and which contains a wealth of information about the symplectic topology. I will discuss the construction of the wrapped Fukaya category for certain completely integrable Hamiltonian systems. These are 2n-dimensional symplectic manifolds carrying a system of n commuting Hamiltonians surjecting onto Euclidean space. This gives rise to a Lagrangian torus fibration with singularities.
Title: Equidistribution of expanding translates of curves in homogeneous spaces and Diophantine approximation.
Abstract:
We consider an analytic curve $\varphi: I \rightarrow \mathbb{M}(n\times m, \mathbb{R}) \hookrightarrow \mathrm{SL}(n+m, \mathbb{R})$ and embed it into some homogeneous space $G/\Gamma$, and translate it via some diagonal flow
Speaker: Misha Belolipetsky
Title: Arithmetic Kleinian groups generated by elements of finite order
Abstract:
We show that up to commensurability there are only finitely many
cocompact arithmetic Kleinian groups generated by rotations. The proof
is based on a generalised Gromov-Guth inequality and bounds for the
hyperbolic and tube volumes of the quotient orbifolds. To estimate the
hyperbolic volume we take advantage of known results towards Lehmer's
problem. The tube volume estimate requires study of triangulations of
Abstract: Adamczewski and Bell proved in the 2013 the Loxton - van der Poorten
conjecture. It says the following. Let f be a Laurent power series (with complex
coefficients) and let \sigma_p be the operator substituting x^p for x in f. Suppose that f satisfies a homogenous polynomial equation in the operator \sigma_p with
coefficients which are rational functions, and a similar equation in the operator \sigma_q where p and q are multiplicatively independent natural numbers. Then f is a rational function.
Abstract: Adamczewski and Bell proved in the 2013 the Loxton - van der Poorten
conjecture. It says the following. Let f be a Laurent power series (with complex
coefficients) and let \sigma_p be the operator substituting x^p for x in f. Suppose that f satisfies a homogenous polynomial equation in the operator \sigma_p with
coefficients which are rational functions, and a similar equation in the operator \sigma_q where p and q are multiplicatively independent natural numbers. Then f is a rational function.
Repeats every week every Sunday until Sun Jun 25 2017 except Sun Apr 30 2017.
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
11:00am to 1:00pm
Location:
Rothberg B221 (CS building)
Speaker: Misha Tyomkyn (TAU)
Title: Lagrangians of hypergraphs and the Frankl-Furedi conjecture
Abstract:
Frankl and Furedi conjectured in 1989 that the maximum Lagrangian of
all r-uniform hypergraphs of given size m is realised by the initial
segment of the colexicographic order. For r=3 this was partially solved
by Talbot, but for r\geq 4 the conjecture was widely open. We verify
the conjecture for all r\geq 4, whenever
$\binom{t-1}{r} \leq m \leq \binom{t}{r}- \gamma_r t^{r-2}$
Title: Algebraic Geometry in an arbitrary variety of algebras and Algebraic Logic
Abstract: I will speak about a system of notions which lead to interesting new problems for groups and algebras as well as to reinterpretation of some old ones.
Title: Character values on compact simple Lie groups
Abstract: This work is part of a joint project with Aner and others to find upper bounds for values of irreducible characters in two related settings: compact simple Lie groups and finite groups of Lie type. I will discuss the first case, presenting bounds of the form
$$|\chi(g)| = O(\chi(1)^\alpha),$$
Abstract: We will discuss the characters of some classes of finite p-groups, in particular groups of maximal class and generalizations, and normally monomial groups.
Title: Holomorphic differentials in positive characteristic
Abstract: This talk is about joint work with Ted Chinburg and Aristides Kontogeorgis.
Let X be a smooth projective curve over an algebraically closed field
k of positive characteristic p. Suppose G is a finite group with non-trivial
