The Topology & Geometry seminar meets on Tuesdays at 13:00 at room 70 in the Ross Building.

2018
Apr
10

The Topology & Geometry seminar meets on Tuesdays at 13:00 at room 70 in the Ross Building.

2018
Apr
10

2018
Apr
24

2018
Mar
27

2016
Jan
20

11:00am to 12:45pm

Ross building, Hebrew University (Seminar Room 70A)

Abstract: One of the first applications of model categories was Quillen homology. Building on the notion of Beck modules, one defines the cotangent complex of an associative or commutative (dg)-algebras as the derived functor of its abelianization. The latter is a module over the original algebra, and its homology groups are called the (Andre'-)Quillen homology. The caveat of this approach is that the cotangent complex is not defined as a functor on the category of all algebras.

2017
May
09

11:00am to 12:00pm

Ross A70.

Abstract: In this talk, I will introduce diffeological spaces and some (co)homology theories on these spaces. I will also talk on Thom-Mather spaces and their (co)homology in the diffeological context.

2017
Jun
13

1:00pm to 1:50pm

Ross 70A

Abstract: The Gromov non-squeezing theorem in symplectic geometry states that is not possible to embed symplectically a ball into a cylinder of smaller radius, although this can be done with a volume preserving embedding. Hence, the biggest radius of a ball that can be symplectically embedded into a symplectic manifold can be used as a way to measure the "symplectic size'' of the manifold. We call the square of this radius times the number \pi the Gromov width of the symplectic manifold. The Gromov width as a symplectic invariant is extended through the notion of "Symplectic Capacity".

2018
Apr
30

2018
May
01

2017
Nov
28

12:00pm to 1:30pm

Room 70A, Ross Building, Jerusalem, Israel

In this talk we present a proof of the Kodaira's theorem that gives a sufficient condition on the existence of an embedding of a Kahler manifold into CPn. This proof is based on the Kodaira Vanishing theorem, using a sheaf-cohomological translation of the embedding conditions.
לאירוע הזה יש שיחת וידאו.
הצטרף: https://meet.google.com/mcs-bwxr-iza

2017
Dec
19

1:00pm to 2:30pm

Room 63, Ross Building, Jerusalem, Israel

I will discuss in the talk David Nadler’s “arborealizaton conjecture” and will sketch its proof. The conjecture states that singularities of a Lagrangian skeleton of a symplectic Weinstein manifold could be always simplified to a finite list of singularities, called ``arboreal”. This is a joint work with Daniel Albarez-Gavela, David Nadler and Laura Starkston.

2017
Dec
12

1:00pm to 2:30pm

Room 70A, Ross Building, Jerusalem, Israel

The (wrapped) Fukaya category of a symplectic manifold is a category whose objects are Lagrangian submanifolds and which contains a wealth of information about the symplectic topology. I will discuss the construction of the wrapped Fukaya category for certain completely integrable Hamiltonian systems. These are 2n-dimensional symplectic manifolds carrying a system of n commuting Hamiltonians surjecting onto Euclidean space. This gives rise to a Lagrangian torus fibration with singularities.

2017
Nov
21

12:00pm to 1:30pm

Room 70A, Ross Building, Jerusalem, Israel

Real and complex Monge-Ampere equations play a central role in several
branches of geometry and analysis. We introduce a quaternionic version
of a Monge-Ampere equation which is an analogue of the famous Calabi
problem in the complex case. It is a non-linear elliptic equation of second
order on so called HyperKahler with Torsion (HKT) manifolds (the latter
manifolds were introduced by physicists in 1990's). While in full generality
it is still unsolved, we will describe its solution in a special case and some

2017
Dec
05

12:00pm to 1:30pm

Room 70A, Ross Building, Jerusalem, Israel

I will describe a topological approach to the robot motion planning problem focusing mainly on the case of aspherical configuration spaces.

2015
Nov
25

11:00am to 12:45pm

Ross building, Hebrew University (Seminar Room 70A)

Abstract: Consider two Lagrangian submanifolds L, L′ in a symplectic manifold (M,ω). A Lagrangian cobordism (W;L,L′) is a smooth cobordism between L and L′ admitting a Lagrangian embedding in (([0,1]×R)×M,(dx∧dy)⊕ω) that looks like [0,ϵ)×{1}×L and (1−ϵ,1]×{1}×L′ near the boundary.
In this talk we will show that under some topological constrains, an exact Lagrangian cobordism (W;L,L′) with dim(W)>5 is diffeomorphic to [0,1]×L.

2016
Jan
20

11:00am to 12:45pm

Ross building, Hebrew University (Seminar Room 70A)

Abstract: One of the first applications of model categories was Quillen homology. Building on the notion of Beck modules, one defines the cotangent complex of an associative or commutative (dg)-algebras as the derived functor of its abelianization. The latter is a module over the original algebra, and its homology groups are called the (Andre'-)Quillen homology. The caveat of this approach is that the cotangent complex is not defined as a functor on the category of all algebras.