Hello everyone,
This week in topology we have Jonathan Spreer returning to give a talk. The talk is available via the usual link:
https://meet.google.com/frv-bgow-byi
Here are the other relevant details:
Title: Linking topology and combinatorics: Width-type parameters of 3-manifolds
Speaker: Jonathan Spreer, University of Sydney
Date: Feb 24, 2021
Time: 3:30 PM
Room: Virtual
Abstract: Many fundamental topological problems about 3-manifolds are algorithmically
solvable in theory but continue to withstand practical computations. In recent years some
of these problems have been shown to allow efficient solutions, if the input 3-manifold comes with a sufficiently ”thin” presentation.
More specifically, a 3-manifold given as a triangulation is considered thin, if the
treewidth of its dual graph is small. I will show how this combinatorial parameter, defined
on a triangulation, can be linked back to purely topological properties of the underlying
manifold. From this connection it can then be followed that, for some 3-manifolds, we
cannot hope for a thin triangulation.
Also, for any Australians stopping by (including the speaker), the talk is Thursday, 8:30AM AEDT
______________________
Neil R. Hoffman
Assistant Professor
Department of Mathematics
523 Math Science Building
Oklahoma State University
Stillwater, OK 74078-1058
405-744-7791
http://math.okstate.edu/people/nhoffman
Hello everyone,
Tomorrow we will be holding usual seminar. I will be speaking. My title and abstract are below.
Title: Exceptional Surgeries in 3-manifolds
Abstract: Bob (Myers) shows that every compact, connected, orientable 3–manifold with no 2– sphere boundary components contains a hyperbolic knot. We use work of Ikeda with an observation of Adams-Reid to show that every 3–manifold subject to the above conditions contains a hyperbolic knot which admits a non-trivial non-hyperbolic surgery, a toroidal surgery in particular. We conclude with a question and a conjecture about reducible surgeries. This is joint work with Ken Baker.
______________________
Neil R. Hoffman
Assistant Professor
Department of Mathematics
523 Math Science Building
Oklahoma State University
Stillwater, OK 74078-1058
405-744-7791
http://math.okstate.edu/people/nhoffman
Hello everyone,
Every though campus is closed, seminar will still go ahead. Henry has told me that he feels comfortable walking like a penguin to safely get from one end of his apartment to the other, so he can give his talk without falling.
See you at 3:30pm today: https://meet.google.com/frv-bgow-byi<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmeet.goog…>
Best,
Neil
______________________
Neil R. Hoffman
Assistant Professor
Department of Mathematics
523 Math Science Building
Oklahoma State University
Stillwater, OK 74078-1058
405-744-7791
http://math.okstate.edu/people/nhoffman
Hello everyone,
Tomorrow in our seminar we have Henry Segerman speaking at 3:30pm central.
The link for the talk is our usual google meet link:
https://meet.google.com/frv-bgow-byi
[https://fonts.gstatic.com/s/i/productlogos/meet_2020q4/v1/web-96dp/logo_mee…]<https://meet.google.com/frv-bgow-byi>
Meet<https://meet.google.com/frv-bgow-byi>
Real-time meetings by Google. Using your browser, share your video, desktop, and presentations with teammates and customers.
meet.google.com
Title: Essential loops in taut ideal triangulations
Abstract: We combinatorialise a technique of Novikov. We use this to prove that, in a three-manifold equipped with a taut ideal triangulation, any vertical or normal loop is essential in the fundamental group.
______________________
Neil R. Hoffman
Assistant Professor
Department of Mathematics
523 Math Science Building
Oklahoma State University
Stillwater, OK 74078-1058
405-744-7791
http://math.okstate.edu/people/nhoffman
