Eventss

2019 Dec 18

Eshnav: Yuval Nov - Notes, Numbers, Tunes and Tunings

6:00pm to 7:00pm


ד"ר יובל נוב: צלילים, מספרים, מנגינות וכיוונים - מפיתגורס עד ימינו

צלילים ומנגינות הם תופעות המקיימות חוקיות מתמטית.  ההרצאה תציג את החוקיות הזו, ובעיקר תעסוק ב"בעיית הכיוון" של כלי נגינה, ובפתרונות המתמטיים שהוצעו לה במהלך הדורות.  ההרצאה מלווה בדוגמאות רבות, ואינה דורשת ידע מוקדם במוזיקה.
2020 Jan 15

Eshnav: Emmanuel Farjoun - The Geometry of Time according to Einstein

6:00pm to 7:00pm

פרופ' עמנואל פרג'ון: הגאומטריה של הזמן - לפי איינשטיין וחבריו
 
 
לפני כ-100 שנה נצפתה סטיה קלה של אורות כוכבים ממסלולם בעוברם ליד השמש. הסטיה התאימה בקירוב לגישתו הגאומטרית של איינשטיין להבנת הזמן וכח הכבידה, הגרוויטציה הניוטונית. ענף רחב ידים של המתמטיקה, הגאומטריה של רימן, גאוס, לוי-צ'יביטה ורבים אחרים קיבל תנופה רבה כבסיס מתמטי לגאומטריה של המרחב-זמן שפותחה ע"י איינשטיין.
2019 Dec 30

NT Seminar - Shai Evra

2:30pm to 3:30pm

Location: 

Ross 70

Title: Ramanujan Conjectures, Density Hypotheses and Applications for Arithmetic Groups.
Abstract: The Generalized Ramanujan Conjecture (GRC) for GL(n) is a central open problem in modern number theory. Its resolution is known to yield applications in many fields, such as: Diophantine approximation and arithmetic groups. For instance, Deligne's proof of the Ramanujan-Petersson conjecture for GL(2) was a key ingredient in the work of Lubotzky, Phillips and Sarnak on Ramanujan graphs.
2019 Dec 23

NT Seminar - Uriya First

2:30pm to 3:30pm

Location: 

Ross 70
Title: The Grothendieck--Serre conjecture for classical groups in low dimensions
Abstract:
A famous conjecture of Grothendieck and Serre predicts that if G is a reductive group scheme over a semilocal regular domain R and X is a G-torsor, then X has a point over the fraction field of R if and only if it has an R-point. Many instances of the conjecture have been established over the years. Most notably, Panin and Fedorov--Panin proved the conjecture when R contains a field.
2019 Dec 17

T&G: Yanir Rubinstein (UMD/WIS), What is the small angle limit of a teardrop?

1:00pm to 2:30pm

Location: 

Room 209, Manchester Building, Jerusalem
In joint work with K. Zhang we construct some explicit canonical geometries on various classes of complex manifolds, following a general symmetry principle pioneered by Calabi in the 70's. Our focus is to allow edge type singularities (that are the natural higher-dimensional analogues of conical Riemann surfaces studied by Picard and others since the 19th century) and study Gromov-Hausdorff limits as the angle in the cone tends to zero.
2019 Dec 31

T&G: Dror Bar-Natan (Toronto), Some Feynman Diagrams in Pure Algebra

1:00pm to 2:30pm

Location: 

Room 209, Manchester Building, Jerusalem, Israel
I will explain how Feynman diagrams arise in pure algebra: how the computation of compositions of maps of a certain natural class, from one polynomial ring into another, naturally leads to a certain composition operation of quadratics and to Feynman diagrams.

I will also explain, with very little detail, how this is used in the construction of some very well-behaved poly-time computable knot polynomials, and then with better detail, why I care about having such invariants.

Joint work with Roland van der Veen.

2020 Jan 07

T&G: Ben Gammage (Harvard and Miami), Mirror symmetry and Hitchin systems

1:00pm to 2:30pm

Location: 

Room 209, Manchester Building, Jerusalem
Mirror symmetry relates the algebraic and symplectic geometry of spaces which are related by dualizing a Lagrangian torus fibration. From the perspective of representation theory this is particularly interesting, with ties to geometric Langlands duality, in cases where the spaces are hyperkähler, and the Lagrangian tori are actually holomorphic Lagrangian. Such spaces, which arise as moduli spaces of four-dimensional field theories, include character varieties, multiplicative quiver varieties, and the "K-theoretic Coulomb branches" of Braverman-Finkelberg-Nakajima.
2020 Jan 06

Special Seminar - Frauke Bleher

4:00pm to 5:00pm

Location: 

Ross 63
Title: Cup products oncurves over finite fields
Abstract: This is joint work with Ted Chinburg.
Let C be a smooth projective curve over a finite field k, and
let l be a prime number different from the characteristic of k.
In this talk I will discuss triple cup products on the first etale
cohomology group of C with coefficients in the constant
sheaf of l-th roots of unity. These cup products are important
for finding explicit descriptions of the l-adic completion of the
etale fundamental group of C and also for cryptographic
2019 Nov 27

Logic Seminar - Omer Ben-Neria

11:00am to 1:00pm

Location: 

Ross building - Room 63
Omer Ben-Neria will speak about Canonical inner models and approximations to the set theoretic universe.  


Abstract: 
The goal of the talk is to introduce the concept of approximating the set theoretic universe V using canonical inner models. 
2019 Dec 19

Basic Notions: Yoel Groman (HUJI) "Hamiltonian dynamics and classical mirror symmetry".

4:00pm to 5:15pm

Location: 

Ross 70
Physicists have observed in the '80s that Calabi-Yau manifolds come in pairs so that quantum cohomology on the one is related to period integrals on the other. This phenomenon, known as mirror symmetry, has since evolved into a deeper understanding that symplectic geometry on a manifold is typically encoded in the complex geometry of another, its mirror. I will discuss in some simple examples of how the relation arises naturally from the study of Hamiltonian Floer cohomology associated with invariant sets of an integrable system.

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