Events & Seminars

2020 Apr 22

Set Theory E-Seminar: Jing Zhang (BIU) - Transformations of the transfinite plane

11:00am to 1:00pm

Location: 

E-seminar Zoom meeting ID 243-676-331

Joint E-seminar of Bar-Ilan University and the Hebrew University


Title: Transformations of the transfinite plane

Abstract: We discuss the existence of certain transformation functions turning pairs of ordinals into triples (or pairs) of ordinals, that allows reductions of complicated Ramsey theoretic problems into simpler ones. We will focus on the existence of various kinds of strong colorings. The basic technique is Todorcevic's walks on ordinals. Joint work with Assaf Rinot.
The Zoom meeting ID is 243-676-331
2020 Apr 06

[HUJI-BGU AGNT Seminar]

Repeats every week every Monday until Sun Jun 28 2020 except Mon Apr 06 2020.
2:15pm to 4:00pm

2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm
2:15pm to 4:00pm

Location: 

https://zoom.us/j/468718180
Join Zoom Meeting
https://zoom.us/j/468718180
Meeting ID: 468 718 180
2020 Apr 21

Tomasz Downarowicz (Wroclaw) Multiorder in countable amenable groups; a promising new tool in entropy theory.

2:00pm to 3:00pm

Location: 

E-seminar Zoom meeting ID 914-412-92758
Abstract: Let G be a countable group. A mutliorder is a collection of 
bijections from G to Z (the integers) on which G acts by a special 
"double shift". If G is amenable, we also require some uniform Folner 
property of the order intervals. The main thing is that mutiorder exists 
on every countable amenable group, which can be proved using tilings.
For now, multiorder provides an alternative formula for entropy of a 
process and we are sure in the nearest future it will allow at produce 
2020 Feb 25

Logic Seminar - Martin Hils

2:00pm to 4:00pm

Location: 

Ross building - Room 63,
Martin Hils will speal about Classification of imaginaries in valued fields with automorphism.


Title: Classification of imaginaries in valued fields with automorphism

Abstract: The imaginaries in the theory ACVF of non-triviallally valued algebraically closed
valued fields are classified by the so-called 'geometric' sorts. This is a fundamental
result due to Haskell-Hrushovski-Macpherson. We show that the imaginaries in
henselian equicharacteristic 0 valued fields may be reduced, under rather general
2020 Mar 24

Matan Seidel (TAU) Random walks on circle packings

2:00pm to 3:00pm

Abstract: A circle packing is a canonical way of representing a planar graph. There is a deep connection between the geometry of the circle packing and the proababilistic property of recurrence/transience of the simple random walk on the underlying graph, as shown in the famous He-Schramm Theorem. The removal of one of the Theorem's assumptions - that of bounded degrees - can cause the theorem to fail. However, by using certain natural weights that arise from the circle packing for a weighted random walk, (at least) one of the directions of the He-Schramm Theorem remains true.
2020 Mar 26

POSTPONED! Be'eri Greenfeld (BIU): How do algebras grow?

12:00pm to 1:00pm

Location: 

Seminar room 209, Manchester Building, Jerusalem, Israel.
How do algebras grow?




The question of `how do algebras grow?', or, which functions can be realized as growth functions of algebras (associative/Lie, or algebras having certain additional algebraic properties) is a major problem in the meeting point of several mathematical fields including algebra, combinatorics, symbolic dynamics and more.


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