Speaker: Karen Meagher, University of Regina Title: Derangement graphs and the intersection density of permutation groups Abstract: Two permutations are intersecting if they both map some $i$ to the same point, equivalently, permutations $\sigma$ and $\pi$ are intersecting if and only if $\pi^{-1}\sigma$ has a fixed point. A set of permutations is called intersecting if any two permutations in the set are intersecting. For any transitive group the stabilizer of a point is an intersecting set. The intersection density of a permutation…

Time: 3:30 pm, Atlantic time, (2:30 pm EST) Wednesday, Mar. 12 Speaker: Ron Gould, Emory University Title: Looking for Saturation in all Kinds of Places Abstract: Given a graph $H$, a graph $G$ is $H$-saturated if $G$ does not contain $H$ as a subgraph, but the addition of any missing edge to $G$ results in a graph containing $H$ as a subgraph. An $H$-saturated graph with the maximum number of edges is called an extremal graph for $H$ and for…

The 2-burning number of a graph Speaker: Ann Trenk, Wellesley College Abstract: We discuss a discrete-time model for the spread of information in a graph, motivated by the idea that people believe a story when they learn of it from two different origins. Similar to the burning number, in this problem, information spreads in rounds and a new source can appear in each round. For a graph $G$, we are interested in $b_2(G)$, the minimum number of rounds until the…

The Burning Number of Large Caterpillars Danielle Cox, Mount Saint Vincent University Abstract: In this talk we will look at the history of the graph burning conjecture and the state of the art. We will also prove the conjecture for sufficiently large p-caterpillars. This is joint work with Kerry Ojakian (CUNY) and Margaret-Ellen Messinger (Mt Allison). Zoom link: https://us02web.zoom.us/j/86861499971?pwd=rTDAaju0TCu24asnaBGvkuNlT11KZ1.1 Meeting ID: 868 6149 9971 Passcode: 325258

Date and Time: Wednesday, October 22, 3.40 pm Atlantic time Speaker: Theodore (Teddy) Mishura, Toronto Metropolitan University Title: Liminal burning the hypercube   Abstract: Liminal burning generalizes both the burning and cooling processes in graphs. In $k$-liminal burning, a Saboteur reveals $k$-sets of vertices in each round, and the Arsonist must choose sources only within these sets. The result is a two-player game with the corresponding optimization parameter $b_k$ called the $k$-liminal burning number. For $k = |V (G)|$, liminal burning is identical to…

Date and Time: Wednesday, October 29, 3.40 pm Atlantic time Speaker: Ben Moore, University of Manitoba Title: Smoothed analysis for graph isomorphism Abstract: I'll describe a simple algorithm which shows the following: Given any graph G, add or remove edges uniformly at random with probability 100/v(G) to create a graph G'. We can test in polynomial time if G' is isomorphic to any other graph H. In other words, graph isomorphism is in P if you add a little bit of randomness to the…

Date and Time: Wednesday, November 5, 3.40 pm Atlantic time Speaker: Kalina Petrova, Institute of Science and Technology Austria Title: Cameron's conjecture on random Latin squares Abstract: A conjecture of Cameron states that the distribution of the number of odd rows in an n x n uniformly random Latin square is approximately binomial with n trials and success probability 1/2. We prove this conjecture in several different senses, including total variation convergence, a local central limit theorem, and a large deviation principle. In fact,…

Date and Time: Wednesday, November 19, 3.40 pm Atlantic time Speaker: Rachel Kirsch, George Mason University Title: Maximizing subgraph density by double counting Abstract: This talk will highlight the use of the method of counting in two ways in recent research on maximizing subgraph density in graphs of bounded degree and clique number. Zoom link: https://us02web.zoom.us/j/88013261876?pwd=XGocyHqvseXY8metPztPoSuulEEejX.1 Meeting ID: 880 1326 1876 Passcode: 357963