Mdtop February 2021

mdtop@mathdept.okstate.edu

1 participants
4 discussions

This week in topology seminar
by Hoffman, Neil 23 Feb '21

23 Feb '21

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

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Tomorrow in seminar
by Hoffman, Neil 16 Feb '21

16 Feb '21

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

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Seminar still going on today
by Hoffman, Neil 10 Feb '21

10 Feb '21

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

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Tomorrow in Topology seminar
by Hoffman, Neil 09 Feb '21

09 Feb '21

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

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Mdtop February 2021