Events & Seminars

2019 Jun 23

Special Talk - Saharon Shelah

4:00pm to 6:00pm

Location: 

Manchester Building, Room 110

Simplicity and universality


Fixing a complete first order theory T, countable for transparency, we had known quite well for which cardinals T has a saturated model. This depends on T of course - mainly of
whether it is stable/super-stable. But the older, precursor notion of having
 a universal notion lead us to more complicated answer, quite partial so far, e.g
the strict order property and even SOP_4 lead to having "few cardinals"
(a case of GCH almost holds near the cardinal). Note  that eg GCH gives a complete
2019 Jun 18

Dynamics and probability: David Jerison (MIT) - Localization of eigenfunctions via an effective potential

2:00pm to 3:00pm

Location: 

Ross 70
We discuss joint work with Douglas Arnold, Guy David, Marcel Filoche and Svitlana Mayboroda.
Consider for the operator $L = -\Delta + V$ with periodic boundary conditions, and more
generally on the manifold with or without boundary. Anderson localization, a significant feature
of semiconductor physics, says that the eigenfunctions of $L$ are exponentially localized with
high probability for many classes of random potentials $V$. Filoche and Mayboroda introduced the
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 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 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.

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