Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
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Friday, July 27, 2018 — 3:30 PM EDT
Title: Algorithms for Rank-1 Bimatrix Games
| Speaker: | Bernhard von Stengel |
| Affiliation: | London School of Economics |
| Room: | MC 5501 |
Abstract:
The rank of a bimatrix game is the matrix rank of the sum of the two payoff matrices.
Thursday, July 26, 2018 — 3:30 PM EDT
Title: Acyclic Colouring of Graphs on Surfaces
| Speaker: | Shayla Redlin |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract: An acyclic k-colouring of a graph G is a proper k-colouring of G with no
Friday, July 20, 2018 — 3:30 PM EDT
Title: Claw-free matroids
| Speaker: | Peter Nelson |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract: A simple binary matroid is claw-free if it has no independent rank-3 flat. I will discuss a structure theorem, obtained jointly with Kazuhiro Nomoto, that classifies these objects exactly.
Thursday, July 19, 2018 — 3:30 PM EDT
Title: Density and Structure of Homomorphism-Critical Graphs
| Speaker: | Evelyne Smith-Roberge |
| Affiliation: | University of Waterloo |
| Room: | MC 5417 |
Abstract:
Let H be a graph. A graph G is H-critical if every proper subgraph of G admits a homomor-
phism to H, but G itself does not.
Tuesday, July 17, 2018 — 3:00 PM EDT
Title: Using Linear Algebra to do Matching Theory
| Speaker: | Justin Toth |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
A matching in a graph is a set of edges with each vertex contained in at most one edge. A perfect matching is a matching in which each vertex is contained in some edge.
Thursday, July 12, 2018 — 3:30 PM EDT
Title: Gaps in the crossing numbers of drawings of the complete graph
| Speaker: | Bruce Richter |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract: In the late 1990’s, a 5-author manuscript circulated proving the existence of intervals of integers that connot occur as the crossing number of a “good” drawing of the complete graph.
Thursday, July 12, 2018 — 1:30 PM EDT
Title: Periodicity on Oriented Graphs by way of Transcendental Number Theory
| Speaker: | Sabrina Lato |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract: Using the adjacency matrix of a graph, it is straightforward to show that perfect state transfer between two vertices at some time t implies that both vertices will be periodic at time 2t.
Friday, July 6, 2018 — 3:30 PM EDT
Title: The coloring problem for restricted graph classes
| Speaker: | Chinh T. Hoang |
| Affiliation: | Wilfred Laurier University |
| Room: | MC 5501 |
Abstract:
Let L be a set of graphs. Free(L) is the set of graphs that do not contain any graph in L as an induced subgraph.
Thursday, July 5, 2018 — 3:30 PM EDT
Title:Generalizing the problem of packing disjoint cycles
| Speaker: | Paul Wollan |
| Affiliation: | University of Rome "La Sapienza" |
| Room: | MC 5479 |
Abstract: A classic result of Erdos and Posa states that there exists a function f such that for all k,
Thursday, July 5, 2018 — 1:30 PM EDT
Title: Edge State Transfer
| Speaker: | Tina Chen |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract: Most research about quantum state transfer on graphs use adjacency matrices as their Hamiltonians and investigate the transfers between single vertex states.