2016
Mar
10

# Eventss

2016
Dec
19

# NT&AG: Edva Roditty-Gershon (University of Bristol), "Arithmetic statistics in function fields"

2:00pm to 3:00pm

## Location:

Manchester Building, Faculty Lounge

Abstract: 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, in the limit q → ∞.

I will also present some recent generalization of these kind of

classical problems.

האירוע הזה כולל שיחת וידאו ב-Google Hangouts.

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, in the limit q → ∞.

I will also present some recent generalization of these kind of

classical problems.

האירוע הזה כולל שיחת וידאו ב-Google Hangouts.

2017
Jun
05

# NT&AG: Simon Marshall (University of Wisconsin), "Endoscopy and cohomology growth on U(n,1) Shimura varieties"

2:00pm to 3:00pm

## Location:

Ros 70

Using the endoscopic classification

of automorphic forms for unitary groups,

I will prove conjecturally sharp upper

bounds for the growth of Betti numbers

in congruence towers of complex

hyperbolic manifolds. This is

joint work with Sug Woo Shin.

האירוע הזה כולל שיחת וידאו ב-Google Hangouts.

הצטרף: https://plus.google.com/hangouts/_/calendar/ODdkc2JxNmlmbjNhZ2U0ODVvb3E3...

of automorphic forms for unitary groups,

I will prove conjecturally sharp upper

bounds for the growth of Betti numbers

in congruence towers of complex

hyperbolic manifolds. This is

joint work with Sug Woo Shin.

האירוע הזה כולל שיחת וידאו ב-Google Hangouts.

הצטרף: https://plus.google.com/hangouts/_/calendar/ODdkc2JxNmlmbjNhZ2U0ODVvb3E3...

2015
Nov
10

2016
Feb
22

# Combinatorics

Repeats every week every Monday until Sun Feb 28 2016 .

10:30am to 12:30pm## Location:

B221 Rothberg (CS and Engineering building)

Speaker: Asaf Nachmias (TAU)

Title: The connectivity of the uniform spanning forest on planar graphs

Abstract:

The free uniform spanning forest (FUSF) of an infinite connected graph G is obtained as the weak limit uniformly chosen spanning trees of finite subgraphs of G. It is easy to see that the FUSF is supported on spanning graphs of G with no cycles, but it need not be connected. Indeed, a classical result of Pemantle ('91) asserts that when G=Z^d, the FUSF is almost surely a connected tree if and only if d=1,2,3,4.

Title: The connectivity of the uniform spanning forest on planar graphs

Abstract:

The free uniform spanning forest (FUSF) of an infinite connected graph G is obtained as the weak limit uniformly chosen spanning trees of finite subgraphs of G. It is easy to see that the FUSF is supported on spanning graphs of G with no cycles, but it need not be connected. Indeed, a classical result of Pemantle ('91) asserts that when G=Z^d, the FUSF is almost surely a connected tree if and only if d=1,2,3,4.

2015
Nov
09

# Combinatorics seminar

Repeats every week every Monday until Mon Nov 23 2015 .

11:00am to 1:00pm11:00am to 1:00pm

## Location:

B221 Rothberg (CS and Engineering building)

Speaker: Clara Shikhelman, TAU

Title: Many T copies in H-free graphs.

Abstract:

For two graphs T and H and for an integer n, let ex(n,T,H) denote

the maximum possible number of copies of T in an H-free graph on n

vertices. The study of this function when T=K_2 (a single edge) is

the main subject of extremal graph theory. We investigate the general

function, focusing on the cases of triangles, complete graphs and trees.

In this talk the main results will be presented as will sketches of

proofs of some of the following:

Title: Many T copies in H-free graphs.

Abstract:

For two graphs T and H and for an integer n, let ex(n,T,H) denote

the maximum possible number of copies of T in an H-free graph on n

vertices. The study of this function when T=K_2 (a single edge) is

the main subject of extremal graph theory. We investigate the general

function, focusing on the cases of triangles, complete graphs and trees.

In this talk the main results will be presented as will sketches of

proofs of some of the following:

2015
Nov
19

# Special Combinatorics seminar: Horst Martini (TU Chemnitz, Germany), "Discrete Geometry in Minkowski Spaces"

12:00pm to 1:00pm

## Location:

Rothberg B314

Title: Discrete Geometry in Minkowski Spaces

Abstract:

In recent decades, many papers appeared in which typical problems of Discrete Geometry are investigated, but referring to the more general setting of finite dimensional real Banach spaces (i.e., to Minkowski Geometry). In several cases such problems are investigated in the even more general context of spaces with so-called asymmetric norms (gauges).

In many cases the extension of basic geometric notions, needed for posing these problems in non-Euclidean Banach spaces, is already interesting enough.

Abstract:

In recent decades, many papers appeared in which typical problems of Discrete Geometry are investigated, but referring to the more general setting of finite dimensional real Banach spaces (i.e., to Minkowski Geometry). In several cases such problems are investigated in the even more general context of spaces with so-called asymmetric norms (gauges).

In many cases the extension of basic geometric notions, needed for posing these problems in non-Euclidean Banach spaces, is already interesting enough.

2016
Jun
15

# CS seminar: June Huh (Princeton & IAS): Matroids in permutohedrons in flag varieties

10:30am to 11:30am

I will talk about the three objects and the two inclusions mentioned in the title from a tropical viewpoint. Possible generalizations will be speculated.

2016
Jan
18

# Combinatorics

11:00am to 1:00pm

## Location:

B221 Rothberg (CS and Engineering building)

No Combsem talk this week -- NogaFest is on!

http://www.math.tau.ac.il/~noga60/program.html

http://www.math.tau.ac.il/~noga60/program.html

2017
Dec
18

# Combinatorics seminar: Orit Raz

11:00am to 12:30pm

## Location:

Eilat Hal at IIAS

Title: Polynomials vanishing on Cartesian products

Abstract:

Let F(x,y,z) be a real trivariate polynomial of constant degree, and let A,B,C be three sets of real numbers, each of size n. How many roots can F have on A x B x C?

2017
Jan
02

# Combinatorics: Ron Holzman (Technion) "Edge-covers in d-interval hypergraphs"

11:00am to 1:00pm

## Location:

Rothberg B220 (CS)

Speaker: Ron Holzman, Technion

Title: Edge-covers in d-interval hypergraphs

Title: Edge-covers in d-interval hypergraphs

2018
Jan
22

# Combinatorics Seminar: Uli Wagner

11:00am to 12:30pm

## Location:

Room 130, Feldman Building

Title: Shellability is NP-complete

2017
Mar
20

# Combinatorics: Doron Puder (TAU) "Meanders and Non-Crossing Partitions"

11:00am to 1:00pm

## Location:

Rothberg B220 (CS bldg)

Speaker: Doron Puder, TAU

Title: Meanders and Non-Crossing Partitions

Abstract: Imagine a long river and a closed (not self-intersecting) racetrack that crosses the river by bridges 2n times. This is called a meander. How many meanders are there with 2n bridges (up to homeomorphisms of the plane that stabilizes the river)? This challenging question, which is open for several decades now, has connections to several fields of mathematics.

Title: Meanders and Non-Crossing Partitions

Abstract: Imagine a long river and a closed (not self-intersecting) racetrack that crosses the river by bridges 2n times. This is called a meander. How many meanders are there with 2n bridges (up to homeomorphisms of the plane that stabilizes the river)? This challenging question, which is open for several decades now, has connections to several fields of mathematics.

2016
Jun
16

# special talk: Bram Petri (Max Planck Institute, Bonn) "The length spectrum of a random surface"

11:00am to 12:00pm

## Location:

Rothberg A410

Speaker: Bram Petri, Max Planck Institute, Bonn

Title: The length spectrum of a random surface

Title: The length spectrum of a random surface

2017
Nov
13

# Combinatorics seminar: Fedor Manin

11:00am to 12:30pm