Online Talk: Jim Geelen

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Please advertise this talk at your home institution. Anyone is welcome to attend! 

YouTube recording: https://www.youtube.com/watch?v=aOpvWW1lBH8

Time: Wednesday, Nov 15 at 3pm ET
Zoom: https://gatech.zoom.us/j/8802082683

Speaker: Jim Geelen, University of Waterloo
Title: Average plane-size

Abstract: In 1941, Eberhard Melchior proved that the average line-length of a simple rank-3 real-representable matroid is less than three.  We discuss a long-overdue analogue of Melchior’s result that the average plane-size of a simple rank-4 real-representable matroid is bounded above by an absolute constant, unless the matroid is the direct-sum of two lines. This is joint work with Rutger Campbell and Matthew Kroeker.

Innovations in Graph Theory and Open Access Journals

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A new diamond open access journal has recently launched called Innovations in Graph Theory.  The journal has an excellent editorial board and will be completely free for both authors and readers.  

Innovations in Graph Theory has informed us that matroid theory submissions are very welcome.  All Matroid Union editors are strong proponents of open access publishing, and so we encourage our readers to consider sending their matroid theory papers to Innovations in Graph Theory.  Other topics related to graph theory are also within the new journal’s scope.  Please see the new journal website for more information about how the new journal will function.  The first issue of the journal is expected to appear in 2024.  

We also would like to point out some other open access journals that accept submissions in matroid theory.  These include the Electronic Journal of Combinatorics, Discrete Mathematics & Theoretical Computer Science, Advances in Combinatorics, Combinatorial Theory, and Discrete Analysis. Please feel free to point out other matroid theory friendly journals that are open access in the comments.

Online Talk: Kathryn Nurse

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Youtube recording: https://www.youtube.com/watch?v=hr17_7c2QSo

Please advertise this talk at your home institution. Anyone is welcome to attend! 

Time: Wednesday, Oct 18 at 3pm ET
Zoom: https://gatech.zoom.us/j/8802082683

Speaker: Kathryn Nurse, Simon Fraser University
Title: Seymour’s 6-flow theorem – a short proof

Abstract: Tutte conjectured in 1954 that every bridgeless graph has a nowhere-zero 5-flow. In 1982, Seymour showed that it is true when 5 is replaced with 6. In this talk, I present a short variation of Seymour’s proof. This work is joint with Matt DeVos.

Online Talk: Nathan Bowler

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YouTube recording: https://www.youtube.com/watch?v=zxNG3ksK76w

Please advertise this talk at your home institution. Anyone is welcome to attend! 

Time: Wednesday, Sep 20 at 3pm ET
Zoom: https://gatech.zoom.us/j/8802082683

Speaker: Nathan Bowler, Universität Hamburg
Title: The $K_4$ game

Abstract: Two players alternately claim edges of a complete graph on infinitely many vertices. The first to claim all edges of a $K_4$ wins. Can the first player force a win? I will explain the history of this question, why it is harder than it seems, and how to win this game.