PIMS lectures
Title: PIMS Undergraduate Event - Twist and Turn: the Story of the Game of Hex
Speaker: Ryan Hayward, University of Alberta
Date and time:
06 Apr 2018,
3:00pm -
4:00pm
Location: David Strong Building, room C116
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(pre-lecture refreshments in DTB A514 @ 2:30 pm)
In 1942, the Danish engineer, poet, and designer Piet Hein invented a new board game and --- with a little help from his friends --- introduced it to readers of the Danish newspaper Politiken. The game became popular: within a year, 50,000 game pads sold.
In 1949 John Nash introduced the game to the Princeton math community, and in 1957 Martin Gardner passed it on to readers of Scientific American.
In this talk for a general audience, I will sketch some big moments in Hex history, ending with an outline of the ideas that make a nearly-superhuman computer Hex program tick.
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Ryan Hayward received his B.Sc. and M.Sc. in mathematics from Queen's University (Kingston) in 1981 and 1982 and his Ph.D. in computer science from McGill University in 1987. His doctoral thesis, Two Classes of Perfect Graphs, was supervised by Vaclav Chvatal. From 1986 through 1989 he was assistant professor in the Department of Computer Science at Rutgers University, after which he held an Alexander von Humboldt fellowship at the Institute for Discrete Mathematics in Bonn for 1989-90.
From 1990 through 1992 he was assistant professor in the Department of Computing Science at Queen's University. From 1992 he was assistant and then associate professor in the Department of Mathematics and Computer Science at the University of Lethbridge, until in 1999 joining the Department of Computing Science at the University of Alberta, where he was promoted to professor in 2004.
He has supervised 13 graduate and 29 undergraduate students, some of whom later became university professors. His current research interests include algorithms for two-player games. His group (including at times Yngvi Bjornsson, Michael Johanson, Broderick Arneson, Philip Henderson, Jakub Pawlewicz, Chao Gao and Aja Huang --- later lead programmer of AlphaGo) has built the world's strongest computer Hex player, and has solved two 1-move 10x10 Hex openings and all smaller-board openings. With Bjarne Toft, he is writing a book on the history of Hex, to be published in 2018.
Many years ago, Ryan rode his bicycle from Vancouver to Lethbridge.
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Title: Mallow Permutations, Stable Matchings and Scaling Limits
Speaker: Omer Angel, University of British Columbia
Date and time:
26 Mar 2018,
3:30pm -
4:20pm
Location: MacLaurin Building, room D110
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We present a new representation of the Mallows permutations to stable matchings on a random bi-partite graph. We also derive new results for the scaling limits of the cycles in the Mallows permutations in terms of the Ethier-Kurtz diffusion.
Joint with Ander Holroyd, Tom Hutchcroft and Avi Levy.
(pre-lecture refreshments @2:45pm in DTB A514)
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Title: The Inverse Eigenvalue Problem of a Graph
Speaker: Leslie Hogben, Iowa State University and American Institute of Mathematics
Date and time:
22 Mar 2018,
3:30pm -
4:20pm
Location: HSD A264
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Inverse eigenvalue problems appear in various contexts throughout mathematics and engineering, and refer to determining whether or not there is a matrix with a prescribed structure (e.g., tridiagonal) and prescribed spectral property (e.g., having a given nullity, or having few distinct eigenvalues). For a given graph G, the associated matrices are real, symmetric, and have off-diagonal nonzero entries exactly where G has edges. The inverse eigenvalue problem of G (abbreviated by IEPG) is to determine the collection of all possible spectra (multisets of eigenvalues) for such matrices. Inverse eigenvalue problems and the background of this problem will be described, together with techniques such as the fundamental work of Colin de Verdière and the Strong Arnold Property. Two recent extensions of the Strong Arnold Property that target a better understanding of all possible spectra and their associated multiplicities will be presented; these are referred to as the Strong Spectral Property and the Strong Multiplicity Property. Applications of these properties to the inverse eigenvalue problem of a graph will be discussed, including the solution of IEPG for all graphs of order at most five.
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