IMBM GEOMETRY & TOPOLOGY MEETINGS

 

12 December 2015

IMBM

 

10:00 - 11:00

Danny Gillam

The Hausdorff topology and Hausdorff quotients

11:00 - 11:30

Break

11:30 - 12:30

Barış Coşkunüzer

Minimal Surfaces with arbitrary topology in H2xR

12:30 - 2:30

Lunch

2:30 - 3:30

Mohan Bhupal

Nonexistence of rational homology disk weak fillings

3:30 - 4:00

Break

 4:00 - 5:00

Takahiro Oba

Compact Stein surfaces as branched covers with same branch sets

 

The talks will be at main lecture hall of Istanbul Center for Mathematical Sciences (IMBM)

 

 

ABSTRACTS

 

The Hausdorff topology and Hausdorff quotients

Danny Gillam - Boğaziçi University

 

In 1914 Felix Hausdorff defined a metric on the set of closed subspaces of a metric space X.  We will give a new interpretation of the resulting topology on the set H(X) of *compact* subsets of X as a "moduli space" for certain "families" of such subsets.  In particular it will follow that the topology on H(X) depends only on the topology of X and not the choice of metric inducing it, so the "Hausdorff space" H(X) is attached naturally to any metrizable space X.  I will explain how H(X) can be used to form a kind of quotient analogous to the Hilbert quotient in algebraic geometry, then I will give some examples and results about this quotient that allow us to identify it in some interesting situations.  This is based on joint work with A. Karan.

 

Minimal Surfaces with arbitrary topology in H2xR

Barış Coşkunüzer - Koç University

 

In this talk, we show that any open orientable surface can be embedded in H^2xR as a complete area minimizing surface. Furthermore, we will discuss the asymptotic Plateau problem in H^2xR, and give a fairly complete solution.

 

Nonexistence of rational homology disk weak fillings of certain singularity links

Mohan Bhupal - METU

 

In this talk, I will show that the Milnor fillable contact structure on the link of a singularity with a specific family of resolution graphs with arbitrary large number of nodes does not admit a weak symplectic filling having the rational homology of the 4-disk. This result provides further evidence to the conjecture that no such weak symplectic filling exists once the mininal resolution tree has at least two nodes. This is a joint  work with Andras Stipsciz.

 

Compact Stein surfaces as branched covers with same branch sets

Takahiro Oba - Tokyo Institute of Technology

 

Loi and Piergallini showed that a smooth compact, connected 4-manifold X with boundary admits a Stein structure if and only if X is a simple cover of a 4-disk D^4 branched along a positive braided surface S in a bidisk D_1^2 \times D_2^2 \approx D^4. For each integer N greater than one, we construct a braided surface S_N in D^4 and simple covers X_{N,1}, X_{N,2}, ... , X_{N,N} of D^4 branched along S_N such that the covers are mutually diffeomorphic, but the Stein structures determined by the covers are mutually not homotopic. Furthermore, by reinterpreting this result in terms of contact topology, we also construct transverse links in the standard contact 3-sphere and contact 3-manifolds, similar to the above. arXiv:1508.01020

 

 

 Meeting Poster

 

For accommodation, Etiler Uygulama Oteli is reasonably priced, and nearby.

Please click Uygulama tab in the top of the page.