Mdtop October 2022

mdtop@mathdept.okstate.edu

1 participants
2 discussions

This week in (virtual) topology seminar
by Hoffman, Neil 31 Oct '22

31 Oct '22

Hello everyone, This week we have Roger Casals, from UC Davis speaking in topology seminar at 3:30 central (1:30 pacific). The talk will be virtual, and the link is here: Topic: Okstate Topology Seminar Time: This is a recurring meeting Meet anytime Join Zoom Meeting https://zoom.us/j/94529451960?pwd=ekkxYUsrRGt5bVdEQWJRN0JOZ04wZz09 Meeting ID: 945 2945 1960 Passcode: JSJDecomp The title and abstract are below: Title: A microlocal invitation to Legendrian links Abstract: We present recent developments in symplectic geometry and explain how they motivated new results in the study of cluster algebras. First, we introduce a geometric problem: the study of Lagrangian surfaces in the standard symplectic 4-ball bounding Legendrian knots in the standard contact 3-sphere. Thanks to results from the microlocal theory of sheaves, which we will survey, we then show that this geometric problem gives rise to an interesting moduli space. In fact, we establish a bridge translating geometric operations, such as Lagrangian disk surgeries, into algebraic properties of this moduli space, such as the existence of cluster algebra structures. The talk is intended for a broad mathematical audience and all key ideas will be introduced and motivated. 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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Eric Sedgwick Today - at 2:30 in MSCS 101
by Hoffman, Neil 04 Oct '22

04 Oct '22

Hi Everyone, Sorry for the late email on this. Things were a little out of whack with the room scheduling. So we have a different time and place for the seminar this week. Today we will hold the seminar at 2:30 in MSCS 101. Topology Seminar Title: Embeddability in R 3 is NP-hard Speaker: Eric Sedgwick, Depaul University Date: Oct 4, 2022 Time: 2:30 PM Room: MSCS 101 Abstract: We prove that the problem of deciding whether a 2–or 3–dimensional simplicial complex embeds into R 3 is NP-hard. This stands in contrast with the lower dimensional cases which can be solved in linear time, and a variety of computational problems in R 3 like unknot or 3–sphere recognition which are in NP∩co-NP (assuming the generalized Riemann hypothesis). Our reduction encodes a satisfiability instance into the embeddability problem of a 3–manifold with boundary tori, and relies extensively on techniques from lowdimensional topology, most importantly Dehn fillings on link complements. This is joint work with Arnaud de Mesmay (CNRS, GIPSA-Lab, France), Yo’av Rieck (University of Arkansas, USA) and Martin Tancer (Charles University, Czech Republic). 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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Mdtop October 2022