2020-2021 ACADEMIC YEAR
Take a look at our previous speakers from past years, and their talks at various institutions. Follow the links to watch their recorded presentations and discussions.
FEBRUARY 4, 2021
TITLE AND ABSTRACT:
"Oriented Graph Colouring - Questions and Answers (but mostly questions)"
The simplicity in the standard definition of graph colouring belies an algebraic interpretation as a homomorphism. This interpretation can be exploited to provide a definition of graph colouring for oriented graphs that, in some sense, respects the orientations of the arcs. In this talk we’ll see how our intuition helps us and hinders us when we explore well-trodden graph colouring territory for oriented graph colouring. In particular, we’ll see how oriented versions of Brooks’ Theorem, the Four-Colour Theorem and Chromatic Polynomials give rise to unexpected results when recast in the context of oriented graphs.
SPEAKER:
Christopher Duffy, Assistant Professor at the University of Saskatchewan in the Department of Mathematics and Statistics
(Learn more about the speaker here)
WHEN:
Thursday, February 4, 2021
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Meet and Greet:
2:00pm-2:30pm CST
Talk:
2:30pm-3:20pm CST
Questions:
3:20pm-3:30pm CST
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The event took place via Zoom due to Covid-19 restrictions.
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Watch recorded talk here:
DECEMBER 3, 2020
TITLE AND ABSTRACT:
"Intracellular Transport of Intermediate Filaments Driven by Antagonistic Motor Proteins"
Abstract:
Intermediate filaments are one of the components of the cytoskeleton; they are involved in cell mechanics, signalling and migration. The organisation of intermediate filaments in networks is the major determinant of their functions in cells. Their spatio-temporal organization in cells results from the interplay between assembly/disassembly processes and different types of transport.
For instance, intermediate filaments, which are long elastic fibers, are transported in cells along microtubules, another component of the cytoskeleton, by antagonistic motor proteins. How elastic fibers are efficiently transported by antagonistic motors is not well understood and is difficult to measure with current experimental techniques. Adapting the tug-of-war paradigm for vesicle-like cargos, a mathematical model is developed to describe the motion of an elastic fiber punctually bound to antagonistic motors. Combining stochastic and deterministic dynamical simulations and qualitative analysis, the asymptotic behaviour of the model, which defines the mode of transport of fibers, is studied [1,2]. The effects of initial conditions, reflecting the intracellular context, model parameters and functionals, describing motors and fiber properties, and noise, outlining other intracellular processes, are characterized.
Work in collaboration with J. Dallon (BYU, Provo, Utah, USA), C. Leduc and S. Etienne-Manneville (Institut Pasteur, Paris, France)
[1] Dallon, J., Leduc, C., Etienne-Manneville, S., and Portet, S. Stochastic modeling reveals how motor protein and filament properties affect intermediate filament transport. J. Theor. Biol. 464: 132-148 (2019).
[2] Portet, S., Leduc, C., Etienne-Manneville, S., Dallon, J. Deciphering the transport of elastic filaments by antagonistic motor proteins. Phys. Rev. E. 99: 042414 (2019).
SPEAKER:
Stéphanie Portet, Professor at the University of Manitoba in the Department of Mathematics
(Learn more about the speaker here)
WHEN:
Thursday, December 3, 2020
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Meet and Greet:
2:00pm-2:30pm CST
Talk:
2:30pm-3:20pm CST
Questions:
3:20pm-3:30pm CST
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WHEN:
The event took place via Zoom due to Covid-19 restricitons.
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Watch recorded talk here:
https://usask.cloud.panopto.eu/Panopto/Pages/Viewer.aspx?id=94fe9617-2f0a-476d-9973-ac86017d83e7
NOVEMBER 5, 2020
TITLE AND ABSTRACT:
"Recent Trends on the Inverse Eigenvalue Problem for Graphs"
Abstract:
Given a simple graph G=(V,E) with V = {1,2,...n}, we associate a collection of real n-by-n symmetric matrices governed by G, and defined as S(G) where the off-diagonal entry in position (i,j) is nonzero iff i and j are adjacent.
The inverse eigenvalue problem for G (IEP-G) asks to determine if a given multi-set of real numbers is the spectrum of a matrix in S(G). This particular variant on the IEP-G was born from the research of Parter and Wiener concerning the eigenvalue of trees and evolved more recently with a concentration on related parameters such as: minimum rank,maximum multiplicity, minimum number of distinct eigenvalues, and zero forcing numbers. An exciting aspect of this problem is the interplay with other areas of mathematics and applications. A novel avenue of research on so-called `strong properties' of matrices, closely tied to the implicit function theorem, provides algebraic conditions on a matrix with a certain spectral property and graph that guarantee the existence of a matrix with the same spectral property for a family of related graphs.
In this lecture, we will review some of the history and motivation of the IEP-G. Building, on the work Colin de Verdi\'ere, we will discuss some of these newly developed `strong properties' and present a number of interesting implications pertaining to the IEP-G.
SPEAKER:
Shaun M. Fallat, Professor at the University of Regina in the Department of Mathematics and Statistics
(Learn more about the speaker here)
WHEN:
Thursday, November 5, 2020
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Meet and Greet:
2:00pm-2:30pm CST
Talk:
2:30pm-3:20pm CST
Questions:
3:20pm-3:30pm CST
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WHERE:
The event took place via Zoom due to Covid-19 restrictions.
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Recorded livestream link coming soon...
Rewatch, rewind and review last years speakers from the 2019-2020 academic year!