Mdtop

mdtop@mathdept.okstate.edu

247 discussions

Today in topology seminar 3pm central (1pm Pacific)
by Hoffman, Neil 02 Nov '21

02 Nov '21

Hello everyone, Today we have Kyle Miller from Berkeley. The link for his talk is: Join Zoom Meeting https://zoom.us/j/94529451960?pwd=ekkxYUsrRGt5bVdEQWJRN0JOZ04wZz09 Meeting ID: 945 2945 1960 Passcode: JSJDecomp His title and abstract are below: Title: The homological arrow polynomial Speaker: Kyle Miller, UC - Berkley Date: Nov 2, 2021 Time: 3:00 PM Room: Virtual Abstract: The Kauffman bracket is a Laurent polynomial invariant of framed unoriented links in the 3-sphere, and it can be calculated via locally defined skein relations. Applying these skein relations to links in other 3-manifolds yields invariants in the Kauffman bracket skein module, which is a relatively complicated object. I will talk about a relatively easy to compute multivariable Laurent polynomial invariant for links in thickened surfaces, obtained as a functional on the skein module, and how an evaluation of this invariant coincides with the arrow polynomial defined by Kauffman and Dye. This homological arrow polynomial is an invariant of virtual links (i.e., it is unchanged under destabilization along vertical annuli in the complement), and it has applications to checkerboard-colorability of virtual links, for example in completing Imabeppu’s characterization of checkerboard colorability of virtual knots with at most four crossings. ______________________ 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

1 0

Today in Topology seminar
by Hoffman, Neil 26 Oct '21

26 Oct '21

Dear Topologists, Today we are very excited to have Adam Clay speaking with us. The seminar link is the same as last week (see below) and Adam's title and abstract are below. https://zoom.us/j/94529451960?pwd=ekkxYUsrRGt5bVdEQWJRN0JOZ04wZz09 Meeting ID: 945 2945 1960 Passcode: JSJDecomp Time: 3:00 PM (central) Title: Virtual Circular orderings, 3-manifolds and covering spaces Speaker: Adam Clay, University of Manitoba Host: Jonathan Johnson Abstract: The L-space conjecture states that for closed, orientable, irreducible 3-manifolds, the properties of being a Heegaard-Floer homology L-space, admitting a co-orientable taut foliation, and having a left-orderable fundamental group are equivalent. Motivated by the left-orderability aspect of this conjecture, I'll introduce circular orderings of groups, and introduce a "circular orderability version" of the L-space conjecture that brings covering spaces into the picture. I'll also discuss several new examples of fundamental groups of 3-manifolds that we know to be circularly orderable, ones that we know are not circularly orderable, and where to go from here. This talk represents joint work with Idrissa Ba. 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

1 0

Today in Topology
by Hoffman, Neil 19 Oct '21

19 Oct '21

Hello everyone, Today Anastasiia Tsvietkova is speaking in the topology seminar. Here title and abstract are below and the zoom link is at the bottom of this email: Title: Polynomially many genus g surfaces in a hyperbolic 3-manifold Speaker: Anastasiia Tsvietkova, Rutgers University, Newark Date: Oct 19, 2021 Time: 3:00 PM Room: Virtual meeting Abstract: We will discuss a universal upper bound for the number of non-isotopic genus g surfaces embedded in a hyperbolic 3-manifold, polynomial in hyperbolic volume. The surfaces are all closed essential surfaces, oriented and connected. This is joint work with Marc Lackenby 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 Join by Skype for Business https://zoom.us/skype/94529451960 ______________________ 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

1 0

Today in Topology Seminar
by Hoffman, Neil 12 Oct '21

12 Oct '21

Hello everyone, We have Topology seminar today at 3pm. Marissa Loving (Georgia Tech) will be speaking. Here title and abstract are below. Title: End-periodic homeomorphisms and volumes of mapping tori Speaker: Marissa Loving, Georgia Tech Date: Oct 12, 2021 Time: 3:00 PM Room: Virtual Abstract: I will discuss volumes of mapping tori associated to irreducible end-periodic homeomorphisms of certain infinite-type surfaces, inspired by a theorem of Brock (in the finite-type setting) relating the volume of a mapping torus to the translation distance of its monodromy on the pants graph. This talk represents joint work with Elizabeth Field, Heejoung Kim, and Chris Leininger. Join Zoom Meeting https://zoom.us/j/94529451960?pwd=ekkxYUsrRGt5bVdEQWJRN0JOZ04wZz09 Meeting ID: 945 2945 1960 Passcode: JSJDecomp ______________________ 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

1 0

Topology Seminar is back
by Hoffman, Neil 28 Sep '21

28 Sep '21

Hello everyone, Topology seminar is back from our hiatus. Today we are very happy to have Jonathan Johnson speaking in seminar. Hello everyone, Today in topology I will be speaking. My title and abstract are below followed by the zoom link: Title: Bi-Orderability Techniques and Double Twist Links Speaker: Jonathan Johnson, Oklahoma State University Date: Sep 28, 2021 Time: 3:00 PM Room: Virtual Abstract: The bi-orderability of link groups has become a fascinating research topic. In this talk, we will survey some useful tools that have been developed to investigate the bi-orderability of link complements, including results of Linnell-Rhemtulla-Rolfsen, Ito, and Kin-Rolfsen. In particular, we will apply these techniques to the double twist link groups. Neil Hoffman is inviting you to a scheduled Zoom meeting. 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 Join by Skype for Business https://zoom.us/skype/94529451960 ______________________ 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

1 0

Today in (Virtual) Topology Seminar
by Hoffman, Neil 07 Sep '21

07 Sep '21

Hello everyone, Today in topology I will be speaking. My title and abstract are below followed by the zoom link: Title: Bounds for arithmetic invariants of 3-manifolds Speaker: Neil Hoffman, Oklahoma State University Date: Sep 7, 2021 Time: 3:00 PM Room: Virtual meeting Abstract: A hyperbolic 3-manifold is the quotient of $H^3$ by $\Gamma$ a discrete subgroup of $PSL(2, C)$. In fact, this subgroup $\Gamma$ carries a substantial amount of arithmetic information. I will discuss some of the background for defining a hyperbolic 3-manifold this way and show how this leads to upper bounds on the degrees of fields used define this data. Finally, I will describe how this perspective fits into joint work with K. Petersen. Neil Hoffman is inviting you to a scheduled Zoom meeting. 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 Join by Skype for Business https://zoom.us/skype/94529451960 ______________________ 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

1 0

Topology seminar tomorrow 4/21
by Hoffman, Neil 20 Apr '21

20 Apr '21

Hello everyone, Tomorrow I am speaking in seminar. I am actually speaking about a question Robert asked about in seminar back when we are in person. My title and abstract are below: Title: Recovering knot diagrams from triangulations Speaker: Neil Hoffman, Oklahoma State University Date: Apr 21, 2021 Time: 3:30 PM Room: https://meet.google.com/frv-bgow-byi Abstract: While the study of knots originally was related to manipulating knot diagrams, one often studies knots by analyzing their complements. In fact, Gordon and Luecke showed two knots are equivalent if and only if their complements are homeomorphic. There are wellknown procedures for constructing a knot complement from a knot diagram. We will analyze the problem from the other perspective: constructing a knot diagram from a triangulated knot complement and describe an algorithm to produce such a diagram. This is joint work Robert Haraway, Saul Schleimer and Eric Sedgwick. ______________________ 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

1 0

Today (Wednesday) in Topology Seminar
by Hoffman, Neil 07 Apr '21

07 Apr '21

We are very happy to have Alex Zupan joining us from University of Nebraska. His title and abstract are below. Title: Complex curves in CP^2 from the perspective of bridge trisections Speaker: Alex Zupan, University of Nebraska Date: Apr 7, 2021 Time: 3:30 PM Room: https://meet.google.com/frv-bgow-byi Abstract: Peter Lambert-Cole and Jeff Meier revealed that bridge trisections of complex curves in CP^2 exhibit elegant structure: Every complex curve admits an inefficient shadow diagram (with respect to the standard genus one trisection) in which shadow arcs form a hexagonal lattice in the torus. Additionally, Lambert-Cole proved a combinatorial classification of symplectic surfaces in CP^2 : A surface that minimizes genus in its homology class is symplectic if and only if it admits a transverse shadow diagram. We prove a complex version of Lambert-Cole’s theorem, that a genus-minimizing surface in CP^2 is complex if and only if it admits a transverse hexagonal lattice diagram. In the process, we find infinite families of efficient hexagonal lattice diagrams for complex curves, and we give a combinatorial characterization of the symplectic isotopy problem in CP^2 ______________________ 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

1 0

Tomorrow in Topology
by Hoffman, Neil 16 Mar '21

16 Mar '21

Hello everyone, Tomorrow we have Nicholas Rouse joining us from Rice. We will meet in the usual place: https://meet.google.com/frv-bgow-byi His title and abstract are below: Title: Arithmetic invariants of Dehn surgery points Speaker: Nicholas Rouse, Rice University Date: Mar 17, 2021 Time: 3:30 PM Room: https://meet.google.com/frv-bgow-byi Abstract: Associated to an orientable, finite volume hyperbolic 3-orbifold is a number field and a quaternion algebra over that field. Such quaternion algebras are classified up to isomorphism by their ramification sets, which is a finite set of prime ideals and embeddings into the real numbers. Chinburg, Reid, and Stover show that orbifolds obtained by Dehn surgery on knots whose Alexander polynomial satisfies some condition have quaternion algebras ramifying above a finite number of rational primes. However, computer experiment suggests that knots that do not satisfy this Alexander polynomial condition have surgeries ramifying above infinitely many distinct primes. We prove this is the case for a family of twist knots and one knot not in that family

1 0

Today in Topology Seminar
by Hoffman, Neil 10 Mar '21

10 Mar '21

Hello everyone, Today in seminar we are very happy to have Jeff Meyer joining us from Cal State - San Bernadino. His title and abstract are below. The link for seminar is the same: https://meet.google.com/frv-bgow-byi Title: Systoles of Arithmetic Manifolds Speaker: Jeff Meyer, Cal State San Bernardino Date: Mar 10, 2021 Time: 3:30 PM Room: Virtual Abstract: Pick your favorite compact space. How short is the shortest closed loop on it? Now look at your favorite cover of this space. Did that loop unwrap to a longer loop? These are systole questions. The systole of a manifold is the minimal length of a non-contractible closed loop. Systoles in arithmetic manifolds have many fascinating relationships with deep problems in number theory, such as Lehmer’s Mahler measure problem. In recent years, there have been numerous papers studying systoles, their bounds, and their growth up covers as you vary the underlying manifolds. In this talk, I will discuss interesting systole problems, survey known results, and present recent work with collaborators Sara Lapan and Benjamin Linowitz. ______________________ 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

1 0

← Newer
1
2
3
4
5
6
7
...
25
Older →

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

Mdtop