Mdtop October 2020

mdtop@mathdept.okstate.edu

1 participants
6 discussions

Fall Redbud
by Hoffman, Neil 28 Oct '20

28 Oct '20

Hello everyone, Because of the ice storm the fall 2020 redbud conference will be on November 8th (originally it was going to be held this weekend). If you want to attend, you can find the registration form on the conference webpage: https://redbud.math.ou.edu/fall-2020/ ______________________ 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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Re: [Mdtop] This week in Topology
by Hoffman, Neil 28 Oct '20

28 Oct '20

Thanks to everyone who got back to me. It looks like we will have critical mass for seminar. See everyone at 3:45. Sent from my iPhone On Oct 28, 2020, at 11:36 AM, William Jaco <jaco(a)math.okstate.edu> wrote: Right now all is good. I can be on. William H. "Bus" Jaco Regents Professor, Grayce B. Kerr Chair Department of Mathematics On Tue, Oct 27, 2020 at 9:37 PM Hoffman, Neil <nhoffman(a)math.okstate.edu<mailto:nhoffman@math.okstate.edu>> wrote: Hello everyone, Sorry for the two emails. First, I hope everyone is okay. With campus closed tomorrow and internet down around Stillwater, I wanted to check in to see if people still could make seminar tomorrow. If we can get a good enough turnout, I am inclined to try to hold seminar tomorrow. If possible, could you send an email back that you can make seminar tomorrow if it’s held? I might have to assume that those that don’t respond are without internet, but if you are getting this on your phone because your home internet is down that would be helpful for me to know. Best, Neil ___________________ Neil Hoffman On Oct 27, 2020, at 3:31 PM, Hoffman, Neil <neil.r.hoffman(a)okstate.edu<mailto:neil.r.hoffman@okstate.edu>> wrote: Hello everyone, This week we are really excited to have Roman Aranda (virtually) coming down from Iowa to speak. His title and abstract are below: 4-manifolds with small trisection genus Speaker: Roman Aranda, University of Iowa Time: Oct 28, 2020, 3:45 PM Room: Virtual meeting https://meet.google.com/frv-bgow-byi<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmeet.goog…> Abstract: In 2016, D. Gay and R. Kirby proved that every closed 4-manifold can be decomposed as the union of three 4-dimensional simple pieces with triple intersection a closed orientable surface of genus g. This decomposition is called a trisection of genus g for M. In 2018, M. Chu and S. Tillmann gave a lower bound for the trisection genus of a closed 4-manifold in terms of the rank of its fundamental group. In this talk, we show that given a group G, there exists a 4-manifold M with fundamental group G with trisection genus achieving Chu-Tillmann’s lower bound. The proof uses techniques of knot theory in simple 3-manifolds. ___________________ Neil Hoffman _______________________________________________ Mdtop mailing list Mdtop(a)mathdept.okstate.edu<mailto:Mdtop@mathdept.okstate.edu> http://cauchy.math.okstate.edu/cgi-bin/mailman/listinfo/mdtop<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fcauchy.mat…>

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This week in Topology
by Hoffman, Neil 27 Oct '20

27 Oct '20

Hello everyone, This week we are really excited to have Roman Aranda (virtually) coming down from Iowa to speak. His title and abstract are below: 4-manifolds with small trisection genus Speaker: Roman Aranda, University of Iowa Time: Oct 28, 2020, 3:45 PM Room: Virtual meeting https://meet.google.com/frv-bgow-byi Abstract: In 2016, D. Gay and R. Kirby proved that every closed 4-manifold can be decomposed as the union of three 4-dimensional simple pieces with triple intersection a closed orientable surface of genus g. This decomposition is called a trisection of genus g for M. In 2018, M. Chu and S. Tillmann gave a lower bound for the trisection genus of a closed 4-manifold in terms of the rank of its fundamental group. In this talk, we show that given a group G, there exists a 4-manifold M with fundamental group G with trisection genus achieving Chu-Tillmann’s lower bound. The proof uses techniques of knot theory in simple 3-manifolds. ___________________ Neil Hoffman

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This week in Topology
by Hoffman, Neil 20 Oct '20

20 Oct '20

This week we have Kate Petersen speaking. Her title and abstract are below. Title: Symmetries and surface detection for SL(2, C) character varieties of 3-manifolds Speaker: Kathleen Petersen, Florida State University Date: Oct 21, 2020 Time: 3:45 PM Room: https://meet.google.com/frv-bgow-byi Abstract: Culler, Morgan, and Shalen pioneered the detection essential surfaces in 3- manifolds through SL(2, C) character varieties. I’ll review these character varieties and detection, then discuss how symmetries of the 3-manifold affect this detection before concluding with some examples. This is joint work with Jay Leach. ______________________ 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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today in topology seminar
by Hoffman, Neil 14 Oct '20

14 Oct '20

Hello everyone, Today Ken Baker is coming by (virtually of course). His title and abstract are below. Title: The Morse-Novikov number of knots: connected sums and cabling Speaker: Ken Baker, University of Miami Date: Oct 14, 2020 Time: 3:45 PM Room: Virtual meeting: https://meet.google.com/frv-bgow-byi<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmeet.goog…> Abstract: We show the Morse-Novikov number of knots in S 3 is additive under connected sum and unchanged by cabling, answering a question of M. Boileau and C. Weber as communicated by A. Pajitnov. ______________________ 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 06 Oct '20

06 Oct '20

Hello everyone, Tomorrow we have Achinta speaking in seminar. The link will be: https://meet.google.com/frv-bgow-byi His title and info can be found here: Title: Some results on the local topology of algebraic sets Speaker: Achinta Nandi, Oklahoma State University Date: Oct 7, 2020 Time: 3:45 PM Room: https://meet.google.com/frv-bgow-byi [https://www.gstatic.com/images/branding/product/2x/meet_96dp.png]<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 Abstract: The topology of an algebraic set near a singular point is of fundamental interest in the study of analytic varieties. In this talk, we shall investigate the local topology of an algebraic set. After a brief description of the basics, we will prove some general facts about algebraic sets and establish results about the local topology of an algebraic set near regular points. A fundamental lemma concerning the existence of real analytic curves on the real algebraic sets will be proved to conclude the talk. Time permitting, we shall discuss some applications of the said lemma, in particular, a fibration theorem which is useful in describing the local topology near singular points. The talk is based on John Milnor’s ”Singular points of complex hypersurfaces”. ______________________ 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 October 2020