Eventss

2019 Jun 27

Basic Notions: Hillel Furstenberg (HUJI) : "Affine (Convex) representations and harmonic functions on symmetric spaces." Part 2

4:00pm to 5:15pm

Location: 

Ross 70
Classical group representation theory deals with group actions on linear spaces; we consider group actions on compact convex spaces, preserving topological and convex structure. We focus on irreducible actions, and show that for a large class of groups - including connected Lie groups - these can be determined. There is a close connection between this and the theory of bounded harmonic functions on symmetric spaces and their boundary values.
2019 Jun 20

Basic Notions: Hillel Furstenberg (HUJI) : "Affine (Convex) representations and harmonic functions on symmetric spaces." Part 1

4:00pm to 5:15pm

Location: 

Ross 70
Classical group representation theory deals with group actions on linear spaces; we consider group actions on compact convex spaces, preserving topological and convex structure. We focus on irreducible actions, and show that for a large class of groups - including connected Lie groups - these can be determined. There is a close connection between this and the theory of bounded harmonic functions on symmetric spaces and their boundary values.
2019 Jun 26

Analysis Seminar - Dvoretzky lecture - Assaf Naor "The (in)compatibility of 3 and 5 dimensional Heisenberg geometry with Lebesgue spaces"

12:00pm to 1:00pm

Location: 

Ross 70
Title: The (in)compatibility of 3 and 5 dimensional Heisenberg geometry with Lebesgue spaces Abstract: The 3-dimensional (discrete) Heisenberg geometry is the shortest-path metric on the infinite graph whose vertex set is the integer grid $\Z^3$ and the neighbors of each integer vector $(a,b,c)$ are the four integer vectors $$(a+ 1,b,c), (a- 1,b,c), (a,b+ 1,c+ a), (a,b- 1,c- a).$$
2019 Jun 12

NO SEMINAR Basic Notions

4:00pm to 5:15pm

Location: 

Ross 70
1) Abstract of Wayne's part: Today, in our modern world, we perceive the physical universe in mathematical terms; whether degrees on longitude and latitude on earth, or in units of space-time beyond our earthly horizons. This talk will present two ancient cuneiform tablets from Babylonia which offer a geometric impression of the physical world as experienced by ancient Babylonians. Comparisons will be made with a range of other ancient mathematical, geographic, and astronomical materials from the cuneiform Ancient Near East. 2) Abstract of Mourtaza's part:
2019 Jun 02

Logic Seminar - Javier de la Nuez Gonzalez

1:00pm to 3:00pm

Location: 

Shprinzak 29
Minimal and non-minimal automorphism groups of homogeneous structures

A Hausdorff topological group G is said minimal if G does not admit any strictly coarser Hausdorff group topology.

Examples include the isometry group of the Urysohn sphere, due to Uspenskij, and Aut(M) for M stable and w-categorical, a deep fact due to Ben Yacov and Tsankov.
2019 Jun 11

Dynamics Lunch: Yotam Smilansky "The space of quasicrystals."

12:00pm to 1:00pm

Abstract: Cut and project point sets are defined by identifying a strip of a fixed n-dimensional lattice (the "cut"), and projecting the lattice points in that strip to a d-dimensional subspace (the "project"). Such sets have a rich history in the study of mathematical models of quasicrystals, and include well known examples such as the Fibonacci chain and vertex sets of Penrose tilings.

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