Regensburg low-dimensional geometry and topology seminar
The seminar is on summer break, and will resume in November 2020.
The seminar takes place on Zoom (see information below) every Tuesday at 16:00 CET (that is 7am on the US west coast, 10am on the US east coast, 10pm in China and 11pm in Korea and Japan).
Talks are split into a 40 minute and a 20 minute part, with a 15 minute tea break in between (you have to brew your own tea).
Talks in fall/winter 2020/21
|November 3||Marco Marengon (MPIM Bonn)||tba|
|November 10||Masaki Taniguchi (Riken)||Filtered instanton Floer homology and the 3-dimensional homology cobordism group||We introduce a family of real-valued homology cobordism invariants r_s(Y) of oriented homology 3-spheres. The invariants r_s(Y) are based on a quantitative construction of filtered instanton Floer homology. Using our invariants, we give several new constraints of the set of smooth boundings of homology 3-spheres. As one of the corollaries, we give infinitely many homology 3-spheres which cannot bound any definite 4-manifold. As another corollary, we show that if the 1-surgery of a knot has negative Froyshov invariant, then the 1/n-surgeries (n>0) of the knot are linearly independent in the homology cobordism group. This is joint work with Yuta Nozaki and Kouki Sato.|
|November 17||Louis-Hadrien Robert (Luxembourg)||Categorification of 1 and of the Alexander polynomial|
|November 24||Sarah Rasmussen (Cambridge)||tba|
|December 1||Tao Li (Boston College)||tba|
|December 8||Ciprian Manolescu (Stanford)||tba|
Past talks in spring 2020
Zoom Meeting ID: 924 2829 6353
The password is the answer to the following riddle (lower case, singular, no article): As a topologist, what do you typically glue together from charts? (Hint: It's not an orbifold).
We encourage you to enable your video, for a more interactive atmosphere. The talks are recorded and made available on this webpage, including audio and video of questions from the audience.