Mdtop

mdtop@mathdept.okstate.edu

247 discussions

Redbud this weekend
by Hoffman, Neil 04 Mar '21

04 Mar '21

Hello everyone, If you haven't yet, consider registering for the redbud conference we are hosting this weekend. https://math.okstate.edu/conferences/redbud/index.html#registration The main page is here. In our biased opinion, it looks like a pretty good conference! https://math.okstate.edu/conferences/redbud/ If you aren't sold yet, I should point out Birch is speaking. 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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This week Hannah Turner
by Hoffman, Neil 02 Mar '21

02 Mar '21

Dear mdtop, This week we have Hannah Turner visiting us (virtually) from the University of Texas. Her title and abstact are below. As always the google meet link is: https://meet.google.com/frv-bgow-byi Speaker: Hannah Turner, University of Texas Time: Wednesday, March 3, 2021, 3:30. Title: Branched cyclic covers and L-spaces Abstract: A 3-manifold is called an L-space if its Heegaard Floer homology is ”simple.” No characterization of all such ”simple” 3-manifolds is known. Manifolds obtained as the double-branched cyclic cover of a knot in the 3-sphere give many examples of L-spaces. In this talk, I’ll discuss the search for L-spaces among higher index branched cyclic covers of knots. In particular, I’ll give new examples of knots whose branched cyclic covers are L-spaces for every index n. This is joint work with Ahmad Issa. ______________________ 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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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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Topology organizational meeting
by Hoffman, Neil 27 Jan '21

27 Jan '21

Hello everyone, Today we have our organizational meeting at 3:30pm. Here is the link: https://meet.google.com/frv-bgow-byi If you can't make the meeting today, but want to speak this semester or invite a speaker let me know and I will be happy to fill in the schedule.

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Organizational meeting next week, time set at 3:30
by Hoffman, Neil 20 Jan '21

20 Jan '21

Hello everyone, The organizational meeting for topology seminar will be next week 1/27/21 at 3:30pm. It seems that the consensus is that 3:30pm is a better time for us. So please note the time. 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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Topology Seminar Meeting time
by Hoffman, Neil 15 Jan '21

15 Jan '21

Hello Everyone, I wanted to take a poll to see if holding seminar at 3pm on Wednesdays would work for everyone. It will of course still be held virtually. Please let me know if this would cause an issue for you. The final pieces of business are: Our organizational meeting will be held the second week of classes. March 6-7, we will be holding the first virtual redbud conference. Let me or Henry know if you are interested in helping out. Best, Neil ___________________ Neil Hoffman

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Final seminar of the semester
by Hoffman, Neil 01 Dec '20

01 Dec '20

Hello everyone, I just wanted to invite you to the final seminar of the semester. We are really happy to have Brandon Bavier from Michigan State coming to speak in our seminar. His title and abstract are below. Title: Guts, Volume, and Skein Modules of 3-Manifolds Speaker: Brandon Bavier, Michigan State University Date: Dec 2, 2020 Time: 3:45 PM central (4:45 PM eastern) Room: Virtual meeting https://meet.google.com/frv-bgow-byi Abstract: When looking at hyperbolic alternating knots in S^3 , there is a relation between the twist number, the Jones polynomial, and the volume of the knot complement. Little is known for general hyperbolic links, or links in other manifolds. We consider hyperbolic links that admit alternating projections on surfaces in compact, irreducible 3-manifolds. Under some mild hypotheses, we are able to show that volume of the link complement is bounded below in terms of a Kauffman bracket function defined on link diagrams on the surface. Further, if the manifold is a thickened surface, we can construct a Jones-type polynomial that is an isotopy invariant that leads to a 2-sided linear bound on the volume of hyperbolic alternating links in the thickened surface ______________________ 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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