Montag,
2011-10-31
16:15 Uhr
|
Raum 404, Eckerstr. 1
Victor Bangert:
(Non-)Integrability of calibrated k-plane fields |
Montag,
2011-11-07
16:15 Uhr
|
Raum 404, Eckerstr. 1
Blaz Mramor (Vrije Universiteit Amsterdam):
Destruction of minimal foliations for finite range Frenkel-Kontorova models
Vortrag im Rahmen des SFB/Transregio 71
Monotone variational recurrence relations such as the Frenkel-
Kontorova lattice, arise in solid state physics and as Hamiltonian
twist maps. Aubry-Mather theory guarantees the existence of minimizers
of every rotation number. They constitute the Aubry-Mather set. When
the rotation number is irrational, the Aubry-Mather set is either
connected - a foliation, or a Cantor set - a lamination. It turns out
that when the rotation number of a minimal foliation is Liouville
(easy to approximate by rational numbers) the foliation can be
destroyed into a lamination by an arbitrarily small smooth
perturbation of the recurrence relation. |
Montag,
2011-11-21
16:00 Uhr
|
Raum 404, Eckerstr. 1
Oliver Fabert:
Computing descendants in symplectic field theory
Symplectic field theory (SFT) assigns to each symplectomorphism (of a closed symplectic manifold) an infinite-dimensional Hamiltonian system with an infinite number of symmetries. While the latter are obtained using descendants, for Hamiltonian symplectomorphisms this leads to the well-known integrable hierarchies of Gromov-Witten theory. In joint work with P. Rossi we study the algebraic structure of descendants, both to find richer geometrical invariants and to answer the question of integrability for general symplectomorphisms. |
Montag,
2011-12-05
16:15 Uhr
|
Raum 404, Eckerstr. 1
Anda Degeratu:
Crepant resolutions of Calabi-Yau orbifolds
A Calabi-Yau orbifold in complex dimension 3 is locally modeled on C^3/G with G a finite subgroup of SL(3,C). When G acts with an isolated fixed point on C^3, a crepant resolution has the structure of an asymptotically locally euclidean (ALE) manifold. Using index theory techniques we derive a geometrical interpretation of the McKay correspondence which relates the geometry of the crepant resolution to the representation theory of the finite group G. This extends a result of Kronheimer and Nakajima to this higher dimensional case. |
Montag,
2011-12-12
16:15 Uhr
|
Raum 404, Eckerstr. 1
Alexander Alexandrov:
Matrix models, enumerative geometry and integrability
Some of generating functions in enumerative geometry are known to be related to matrix integrals and
classical integrable hierarchies of KP/Toda type. In recent years it become clear that the partition functions of the
this still not completely described set of models posses other nice properties such
as cut-and-join-type representations, random partition descriptions and Virasoro-type constraints.
I will explain some of the aforementioned properties and relations between them for three important models, namely Hermitian matrix model,
Kontsevich-Witten tau-function and generating function of Hurwitz numbers. |
Montag,
2011-12-19
16:15 Uhr
|
Raum 404, Eckerstr. 1
Patrick Emmerich:
Rigidity of complete Riemannian cylinders without conjugate points |
Montag,
2012-01-09
16:15 Uhr
|
Raum 404, Eckerstr. 1
Magnus Engenhorst:
Quadratic Differentials and BPS states |
Montag,
2012-01-16
16:15-17:45 Uhr
|
Raum 404, Eckerstr. 1
Dr. Emanuel Scheidegger:
Counting curves on Calabi-Yau manifolds
We give an overview on Gromov-Witten theory of Calabi-Yau manifolds. In particular, we study generating functions of Gromov-Witten invariants and explain their reformulations by physicists. Our focus will lie on those cases for which these functions turn out or are expected to be modular forms. |
Montag,
2012-01-23
16:15 Uhr
|
Raum 404, Eckerstr. 1
Anda Degeratu:
Invariants of elliptically fibered Calabi-Yau 3-folds
We look at a special type of elliptically fibered Calabi-Yau 3-folds arising via the heterotic/F-theory string-string duality. We describe the imprint of this duality on the geometry and topology of the Calabi-Yaus. This is joint work with Katrin Wendland. |
Montag,
2012-02-06
16:15 Uhr
|
Raum 404, Eckerstr. 1
Nadja Fischer, Anja Fuchshuber:
The Family Index Theorem and the Eta-Form
We'll give an overview of the index theorem in different situations and then we'll concentrate on families of closed manifolds. We are interested in the eta-form and its convergence at infinity and zero.
Our presentation will be based on "Heat Kernels and Dirac Operators" by Berline, Getzler and Vergne. |
Montag,
2012-02-13
16:15 Uhr
|
Raum 404, Eckerstr. 1
Natalie Peternell:
Kozykel für charakteristische Klassen
In meinem Vortrag konstruiere ich nach Brylinski-Mc Laughlin Kozykeldarstellungen für charakteristische Klassen in der glatten Deligne-Kohomologie. |
