Eventss

2017 Jan 02

NT&AG: Ehud de Shalit (HUJI), "Geometry modulo p of some unitary Shimura varieties"

2:00pm to 3:00pm

Location: 

Ros Building, 70A
Abstract: This talk will be about joint work with Eyal Goren about the
structure of Picard modular surfaces at a prime p which is inert in the
underlying quadratic imaginary field. The main tool for studying the bad
reduction of Shimura varieties is the theory of local models (due to de
Jong and Rapoport-Zink). Our results concern global geometric questions
which go beyond the theory of global models. For example, we are able to
count supersingular curves on the Picard surface. We also study certain
2017 Jun 05

NT&AG: Simon Marshall (University of Wisconsin), "Endoscopy and cohomology growth on U(n,1) Shimura varieties"

2:00pm to 3:00pm

Location: 

Ros 70
Using the endoscopic classification
of automorphic forms for unitary groups,
I will prove conjecturally sharp upper
bounds for the growth of Betti numbers
in congruence towers of complex
hyperbolic manifolds. This is
joint work with Sug Woo Shin.
‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts.
הצטרף: https://plus.google.com/hangouts/_/calendar/ODdkc2JxNmlmbjNhZ2U0ODVvb3E3...
2016 Dec 05

NT&AG: Michael Temkin (Hebrew University), "Topological transcendence degree"

2:00pm to 3:00pm

Abstract: my talk will be devoted to a basic theory of extensions of
complete real-valued fields L/K. Naturally, one says that L is
topologically-algebraically generated over K by a subset S if L lies
in the completion of the algebraic closure of K(S). One can then define
topological analogues of algebraic independence, transcendence degree, etc.
These notions behave much more wierd than their algebraic analogues. For example,
there exist non-invertible continuous K-endomorphisms of the completed
2016 Nov 28

NT&AG: Boris Zilber (University of Oxford), "On algebraically closed field of characteristic 1"

2:00pm to 3:00pm

Location: 

Ros Building, 70A
Abstract: I will start with a motivation of what algebraic (and model-theoretic) properties
an algebraically closed field of characteristic 1 is expected to have. Then I will explain
how these properties can be obtained by the well-known in model theory Hrushovski's
construction and then formulate very precise axioms that such a field must satisfy.
The axioms have a form of statements about existence of solutions to systems
of equations in terms of a 'multi-dimansional' valuation theory and the validity
2018 Jan 01

NT&AG: Efrat Bank (University of Michigan), "Correlation between primes in short intervals on curves over finite fields"

2:00pm to 3:00pm

Location: 

Room 70A, Ross Building, Jerusalem, Israel
In this talk, I present an analogue of the Hardy-Littlewood conjecture on the asymptotic distribution of prime constellations in the setting of short intervals in function fields of smooth projective curves over finite fields.
I will discuss the definition of a "short interval" on a curve as an additive translation of the space of global sections of a sufficiently positive divisor E by a suitable rational function f, and show how this definition generalizes the definition of a short interval in the polynomial
setting.
2017 Apr 03

NT&AG: Izzet Coskun (University of Illinois at Chicago), "Birational geometry of moduli spaces of sheaves on surfaces"

4:00pm to 5:00pm

Location: 

Tel Aviv University, Schreiber building, 209
Abstract: In the last five years Bridgeland stability has revolutionized
our understanding of the geometry of moduli spaces of sheaves on surfaces,
allowing us to compute ample and effective cones and describe different
birational models. In this talk, I will survey some of my joint work with
Daniele Arcara, Aaron Bertram, Jack Huizenga and Matthew Woolf on the
birational geometry of moduli spaces of sheaves on the plane. I will
describe the ample and effective cones of these moduli spaces,
2016 Jan 12

Number theory: Ted Chinburg (Univ. of Pennsylvania) "Chern classes in Iwasawa theory"

10:30am to 11:45am

Location: 

Ross Building, room 70A
Many of the main conjectures in Iwasawa theory can be phrased as saying
that the first Chern class of an Iwasawa module is generated by a p-adic
L-series.
In this talk I will describe how higher Chern classes pertain to the higher
codimension behavior of Iwasawa modules. I'll then describe a template
for conjectures which would link such higher Chern classes to elements
in the K-theory of Iwasawa algebras which are constructed from tuples of
Katz p-adic L-series. I will finally describe an instance in which a result of
2016 Mar 17

Number theory

Repeats every week every Thursday until Thu Jun 16 2016 except Thu Apr 14 2016.
12:00pm to 1:15pm

12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm
12:00pm to 1:15pm

Location: 

Ross Building, room 63, Jerusalem, Israel
In his investigation of modular forms of half-integral weight, Shimura established, using Hecke theory, a family of relations between eigneforms of half-integral weight k+1/2 with a given level 4N and character chi and cusp forms of weight 2k and character chi^2.
The level being subsequently determined by Niwa to be at most 2N.
2017 Dec 25

NG&AT: Zev Rosengarten (Stanford University), "Tamagawa Numbers of Linear Algebraic Groups Over Function Fields"

2:00pm to 3:00pm

Location: 

Room 70A, Ross Building, Jerusalem, Israel
Abstract: In 1981, Sansuc obtained a formula for Tamagawa numbers of reductive groups over number fields, modulo some then unknown results on the arithmetic of simply connected groups which have since been proven, particularly Weil's conjecture on Tamagawa numbers over number fields. One easily deduces that this same formula holds for all linear algebraic groups over number fields. Sansuc's method still works to treat reductive groups in the function field setting, thanks to the recent resolution of Weil's conjecture in the function field setting by Lurie and Gaitsgory.
2017 Feb 27

NT&AG: Stephen Lichtenbaum (Brown University), "A conjectured cohomological description of special values of zeta-functions"

2:00pm to 3:00pm

Location: 

Ross 70A
Abstract: Let X be a regular scheme, projective and flat over Spec Z. We
give a conjectural formula in terms of motivic cohomology, singular
cohomology and de Rham cohomology for the special value of the
zeta-function of X at any rational integer. We will explain how this
reduces to the standard formula for the residue of the Dedekind
zeta-function at s = 1.
‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts.
2016 Apr 21

Number Theory: Benjamin Matschke (University of Bordeaux) "A database of rational elliptic curves with given bad reduction"

2:00pm to 3:15pm

Location: 

TBA
In this talk we present a database of rational elliptic curves with
good reduction outside certain finite sets of primes, including the
set {2, 3, 5, 7, 11}, and all sets whose product is at most 1000.
In fact this is a biproduct of a larger project, in which we construct
practical algorithms to solve S-unit, Mordell, cubic Thue, cubic
Thue--Mahler, as well as generalized Ramanujan--Nagell equations, and
to compute S-integral points on rational elliptic curves with given
Mordell--Weil basis.

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