Events & Seminars

2018 Oct 31

Logic Seminar - Yatir Halevi

11:00am to 1:00pm

Location: 

Ross 63

Around the stable and dependent fields conjecture


Abstract: The stable fields conjecture asserts that every infinite stable field is separably closed.
We will talk a bit about the history of this conjecture, its connection to an analogous conjecture on dependent fields and some of their consequences.
Finally, we will end by proving the conjecture for fields of finite dp-rank.
2018 Oct 29

NT&AG: Michael Temkin (HUJI), ""Differential forms on Berkovich curves"

2:30pm to 3:30pm

Location: 

Room 70A, Ross Building, Jerusalem, Israel
The moduli space of smooth curves with a chosen differential form has a natural stratification by the pattern of zeros of the form. In a recent paper of Bainbridge-Chen-Gendron-Grushevsky-Moeller, one used a complicated complex-analytic technique to explicitly describe a compactification of these strata. In a joint work in progress with I. Tyomkin we provide an algebraic proof of these results based on studying differential forms on Berkovich curves over fields of residual characteristic zero.
2018 Nov 06

Jon Aaronson (TAU) On the bounded cohomology of actions of multidimensional groups.

2:15pm to 3:15pm

Although each cocycle for a action of the integers is specified by the sequence of Birkhoff sums of a function, it is relatively difficult to specify cocycles for the actions of multidimensional groups such as $\Bbb Z^2$. We'll see that if $(X,T)$ is a transitive action of the finitely generated (countable) group $\Gamma$ by homeomorphism of the polish space $X$, and $\Bbb B$ is a separable Banach space, there is a cocycle $F:\Gamma\times X \to\Bbb B$ with each $x\mapsto F(g,x)$ bounded and continuous so that the skew product action $(X x \Bbb B,S)$ is transitive where
2018 Oct 21

Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

Location: 

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity. Recommended prerequisites: basic commutative algebra
2018 Dec 23

Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

Location: 

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity. Recommended prerequisites: basic commutative algebra
2018 Dec 16

Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

Location: 

Ross 70A
Abstract: The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation. We shall present the classical methid, and give an approachable introduction to Kim's method. I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
2018 Nov 04

Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

Location: 

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity. Recommended prerequisites: basic commutative algebra
2018 Oct 21

Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

Location: 

Ross 70A
Abstract: The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation. We shall present the classical methid, and give an approachable introduction to Kim's method. I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
2019 Jan 13

Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

3:00pm to 5:00pm

Location: 

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity. Recommended prerequisites: basic commutative algebra
2018 Dec 30

Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

12:00pm to 2:00pm

Location: 

Ross 70A
Abstract: The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation. We shall present the classical methid, and give an approachable introduction to Kim's method. I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html

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