Online Talk: James Oxley

YouTube recording: https://www.youtube.com/watch?v=fKgb4XxhQzk

Time: Wednesday, April 24 at 3pm ET
Zoom: https://gatech.zoom.us/j/8802082683

Speaker: James Oxley, Louisiana State University
Title: The legacy of Dominic Welsh

Abstract: Dominic Welsh wrote the first comprehensive text on matroids. He supervised 28 doctoral theses and wrote over 100 papers and five books. As impressive as these numbers are, they fail to truly capture the spirit of the man who inspired generations of students and imbued them with not only a love of mathematical beauty but with a deep and abiding affection for the man himself. Dominic died in November, 2023. The speaker will attempt to capture some of the key aspects of his legacy.

Online Talk: James Davies

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

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

Time: Wednesday, Jan 24 at 3pm ET
Zoom: https://gatech.zoom.us/j/8802082683

Speaker: James Davies, University of Cambridge
Title: Odd distances in colourings of the plane

Abstract: We prove that every finite colouring of the plane contains a monochromatic pair of points at an odd integer distance from each other. The proof uses a spectral method.

Online Talk: Jim Geelen

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.

Online Talk: Kathryn Nurse

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.