# Colloquium

The weekly colloquium features a talk by an invited speaker. Topics vary and include all areas of mathematics.

The colloquium takes place on Tuesdays, 14:00 in room 614, 6’th floor of the Science and Education Building. For further details, please contact the colloquium coordinator, Dr. Oren Ben-Bassat.

## Colloquium: Tuesday, January 24, 2 pm. Speaker: Chloé Perin (Hebrew University). Title: “First-order logic on the free group and geometry”.

We will give an overview of questions one might ask about the first-order theory of free groups and related groups: how much information can first-order formulas convey about these groups or their elements, what algebraic interpretation can be given for…

## Colloquium: Tuesday, January 17, 2 pm. Speaker: Shahar Nevo (Bar Ilan). Title: “Differential inequalities and normality”.

Following Marty’s Theorem we present recent results about differential inequalities that imply (or not) some degree of normality. We deal with inequalities with reversed sign of inequality than that in Marty’s Theorem, i.e. |f^{(k)}(z)|> h(|f(z)|). Based on joined work with…

## Colloquium: Tuesday, January 10, 2 pm. Speaker: Yosef Yomdin (Weizmann). Title: “Smooth parametrizations, and their applications in dynamics, analysis, and Diophantine geometry”.

Smooth parametrization consists in a subdivision of a mathematical object under consideration into simple pieces, and a parametric representation of each piece, while keeping control of high order derivatives. The main goal of this talk is to provide an overview…

## Colloquium: Tuesday, January 3, 2 pm. Speaker: Mikhail Borovoi (Tel Aviv). Title: “Reeder’s puzzle and orbits in real homogeneous spaces”.

In the talk I shall describe a puzzle for children. We have a pile of stones and a graph D with n vertices. At most one stone may be placed on a vertex, so a vertex has one of two…

## Colloquium: Tuesday, December 27, 12 pm. Speaker: Uriya First (UBC). Title: “Ramanujan Complexes”.

Ramanujan graphs are regular graphs whose vertex adjacency matrix has “very condensed” spectrum. The latter manifests in many desired combinatorial properties, most notable of which is the fact that Ramanujan graphs are expanders, i.e. they admit high connectivity among their…

## Colloquium: Tuesday, December 20, 2 pm. Speaker: Edva Roditty-Gershon (Bristol). Title: “Arithmetic statistics in function fields”.

In the talk I will discuss classical problems concerning the distribution of square-full numbers and their analogues over function fields. The results described are  in the context of the ring Fq[T] of polynomials over a finite field Fq of q elements,…

## Colloquium: Tuesday, December 6, 2 pm. Speaker: Tali Pinsky (Tata institute – India). Title: “Could the Lorenz flow be hyperbolic?”.

I will describe the theory of hyperbolic dynamical systems, and then describe a new approach to chaotic flows in dimension three, using knot theory. I’ll use this to show that, surprisingly, the famous Lorenz flow on R^3 can be related…

## Colloquium: Tuesday, November 29, 2 pm. Speaker: Boris Zilber (Oxford). Title: “A geometric semantics of algebraic quantum mechanics”.

We approach the formalism of quantum mechanics from the logician point of view and treat the canonical commutation relations and the conventional calculus based on it as an algebraic syntax of quantum mechanics. We then aim to establish a geometric…

## Colloquium: Tuesday, November 22, 2 pm. Speaker: Yehuda Pinchover (Technion). Title: “Some aspects of Hardy-type inequalities”.

: In 1921, Landau wrote a letter to Hardy including a proof of the inequality \begin{align*} \sum_{n=0}^{\infty}|\phi(n)-\phi(n+1)|^{p}\geq \left(\frac{p-1}{p}\right)^{p}\sum_{n=1}^{\infty}\frac{|\phi(n)|^{p}}{n^{p}} \end{align*} which holds for all finitely supported $\phi:\N_0\to\R$ such that $\phi(0)=0$ (here $1<p<\infty$ is a fixed number). This inequality was stated before…

## Colloquium: Tuesday, November 1, 2 pm. Speaker: Eitan Sayag (Ben Gurion). Title: “Spherical functions, spherical distributions and their applications”.

Periods of automorphic forms provides an important tool to classify automorphic representations and arise time and time again in problems with arithmetic origin. Motivated by that, I shall describe some of our investigation of local counterparts of these periods that…

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