CanaDAM 2011 University of Victoria, May 31 - June 3, 2011 www.cms.math.ca//2011

# Schedule - Contributed Minisymposia

Please note that schedules are subject to change without notice, particularly changes within a given session.

 Applications of Graph Theory To Chemistry I (CM15) Org: Patrick Fowler (University of Sheffield) This session and the following one explore applications of Graph Theory to Chemistry. Part I: Conduction and aromaticity in carbon networks, and computer generation of conjectures about graph parameters and chemical invariants. Thursday June 2 10:10 - 10:35 Patrick Fowler (University of Sheffield), Currents in molecules, Cornett A229 10:40 - 11:05 Milan Randic (National Insitute of Chemistry, Ljubljana), Graph Theoretical Models of Ring Currents in Conjugated Hydrocarbons, Cornett A229 11:10 - 11:35 Irene Sciriha (University of Malta), Interlacing and Omni-Conduction in Single Molecules, Cornett A229 11:40 - 12:05 Craig Larson (Virginia Commonwealth University), Conjecturing with GrInvIn, Cornett A229 Applications of Graph Theory to Chemistry II (CM18) Org: Wendy Myrvold (University of Victoria) This session and the previous one explore applications of Graph Theory to Chemistry. Part II: Fullerenes and algorithms for generating graphs representing classes of chemical molecules. Thursday June 2 15:15 - 15:40 Wendy Myrvold (University of Victoria), Independent Sets of Fullerenes, Cornett A229 15:45 - 16:10 Nico Van Cleemput (Ghent University), CaGe - A Chemical and Abstract Graph Environment, Cornett A229 16:15 - 16:40 Dong Ye (West Virginia University), Resonance in Fullerenes, Cornett A229 16:45 - 17:10 Elizabeth J. Hartung (Syracuse University), Fullerene Parameters: A Colorful Approach, Cornett A229 Applications of Matroid Theory in Coding Theory I (CM22) Org: Irene Márquez Corbella (University of Valladolid) This minisymposium is aimed at bringing together researchers from all fields related to the applications of matroid theory in coding theory. Since much of the work related to this subject is still ongoing, the minisymposium will provide a stimulating atmosphere where experts will be able not only to report their recent results, but also to propose new guidelines of research and discuss open questions. It will also give us the opportunity to present the interest and the potential applications of this topic to the rest of the scientific community. Friday June 3 10:10 - 10:35 Thomas Britz (University of New South Wales (Australia)), Duality theorems for graphs, codes, and matroids., Cornett A229 10:40 - 11:05 Relinde Jurrius (Eindhoven University of Technology (Netherlands)), Truncation formulas for invariant polynomials of matroids and geometric lattices., Cornett A229 11:10 - 11:35 Gary Gordon (Lafayette College), Generalizations of matroid duality, Cornett A229 11:40 - 12:05 Graham Farr (Monash University (Australia)), Transforms, minors, binary functions and generalised Tutte polynomials, Cornett A229 Applications of Matroid Theory in Coding Theory II (CM24) Org: Edgar Martínez Moro (University of Valladolid) This minisymposium is aimed at bringing together researchers from all fields related to the applications of matroid theory in coding theory. Since much of the work related to this subject is still ongoing, the minisymposium will provide a stimulating atmosphere where experts will be able not only to report their recent results, but also to propose new guidelines of research and discuss open questions. It will also give us the opportunity to present the interest and the potential applications of this topic to the rest of the scientific community. Friday June 3 15:15 - 15:40 Irene Márquez Corbella (University of Valladolid (Spain)), Matroid decomposition and minimal codewords II, Cornett A229 15:45 - 16:10 Pradeep Sarvepalli (University of British Columbia (Vancouver)), Quantum codes and symplectic matroids, Cornett A229 16:15 - 16:40 Keisuke Shiromoto (Kumamoto University (Japan)), Codes over rings and matroids., Cornett A229 16:45 - 17:10 Edgar Martínez Moro (University of Valladolid), Matroid decomposition and minimal codewords, Cornett A229 Chromatic Numbers of Graphs (CM11) Org: Joan Hutchinson (Macalester College) Many variations on the classic chromatic number of a graph have emerged in recent years, sometimes to illuminate that chromatic number and other times for the sake of the new variation and its applications. In this mini-symposium the variations of list-coloring, co-chromatic number, subchromatic number, and 1-defective colorings will be presented, along with the interaction between colorings as measured by the canonical coloring graph of a graph. Wednesday June 1 15:15 - 15:40 John Gimbel (University of Alaska at Fairbanks), Defective chromatic and cochromatic numbers, Cornett A120 15:45 - 16:10 Ruth Haas (Smith College), The Canonical Coloring Graph, Cornett A120 16:15 - 16:40 Joan Hutchinson (Macalester College), List-coloring extension results for planar graphs, Part I, Cornett A120 16:45 - 17:10 Michelle Lastrina (Iowa State University), List-coloring extension results for planar graphs, Part II, Cornett A120 17:15 - 17:40 Karen L. Collins (Wesleyan University, Middletown CT 06459-0128), Bounds on the distinguishing chromatic number of a graph, Cornett A120 Colourings, Independence, and (Forbidden) Subgraphs (CM25) Org: Ingo Schiermeyer (Technical University Freiberg, Germany) There is a great variety of results for vertex-colourings and independence in graphs in terms of forbidden subgraphs. One of the most well-known is the Strong Perfect Graph Theorem. Edwards has shown the following approach: If a graph $G$ has a dominating set $D$, then $3$-colourability can be decided in time $O(3^{|D|} \cdot |E(G)|)$. Using a result of Bacs\'o and Tuza that a $P_5$-free graph has a dominating clique or a dominating $P_3,$ Randerath and Schiermeyer showed that $3$-colourability can be decided in polynomial time for $P_5$-free and $P_6$-free graphs. Friday June 3 15:15 - 15:40 Ingo Schiermeyer (Technical University Freiberg, Germany), Graphs with rainbow connection number two, Cornett A120 15:45 - 16:10 Vadim Lozin (University of Warwick, UK), Vertex 3-colorability of claw-free graphs, Cornett A120 16:15 - 16:40 Anja Kohl (Technical University Freiberg, Germany), Investigating the $b$-chromatic number of bipartite graphs by using the bicomplement, Cornett A120 16:45 - 17:10 Stephan Matos Camacho (Technical University Freiberg, Germany), Stars in Minimum Rainbow Subgraphs, Cornett A120 Convexity and Metric Graph Theory I (CM12) Org: José Cáceres (Universidad de Almería, Almería (Spain)) In a network, the most natural question about two vertices is whether or not they are connected, and the second one could be asking for the distance between them. Thus the study of graphs as metric spaces has been always an important part of the field. This minisimposium and the following one intend to show those recent developments in metric frameworks as convexity that may lead to new perspectives on old questions. Wednesday June 1 15:15 - 15:40 Robert Bailey (Department of Mathematics and Statistics University of Regina Regina, SK Canada), A matrix method for resolving sets in Johnson graphs, Cornett A229 15:45 - 16:10 Alberto Márquez (Departamento de Matemática Aplicada I Universidad de Sevilla Sevilla, Spain), Some question about metric dimension of some families of graphs, Cornett A229 16:15 - 16:40 Mercè Mora (Departament de Matemàtica Aplicada II Universitat Politècnica de Catalunya Barcelona, Spain), Geodetic and hull numbers in strong product graphs, Cornett A229 16:45 - 17:10 José Cáceres (Departamento de Estadística y Matemática Aplicada Universidad de Almería Almería, Spain), Metric dimension in infinite but locally finite graphs, Cornett A229 17:15 - 17:40 Michael Young (Iowa State University), Disjoint Homometric Sets in Graphs, Cornett A229 Convexity and Metric Graph Theory II (CM19) Org: José Cáceres (Universidad de Almería, Almería (Spain)) In a network, the most natural question about two vertices is whether or not they are connected, and the second one could be asking for the distance between them. Thus the study of graphs as metric spaces has been always an important part of the field. This minisimposium and the previous one intend to show those recent developments in metric frameworks as convexity that may lead to new perspectives on old questions. Thursday June 2 15:15 - 15:40 Mitre Dourado (COPPE Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ Brazil), Complexity aspects of graph convexity, Cornett A120 15:45 - 16:10 Morten Nielsen (Department of Mathematics and Statistics Thompson Rivers University Kamloops, BC Canada), Helly theorems for convex sets in graphs, Cornett A120 16:15 - 16:40 Ignacio M Pelayo (Departament de Matemàtica Aplicada III Universitat Politècnica de Catalunya Barcelona, Spain), Dominating location in graphs, Cornett A120 16:45 - 17:10 Ortrud R Oellermann (Department of Mathematics and Statistics University of Winnipeg Winnipeg, MB Canada), Separation Properties for 3-Steiner and 3-Monophonic Convexity in Graphs, Cornett A120 Covering Arrays, Generalizations and Software Testing Applications I (CM4) Org: Peter Danziger (Ryerson University), Lucia Moura (University of Ottawa) and Brett Stevens (Carleton University) Covering arrays are combinatorial designs that generalize orthogonal arrays, and have been more intensively studied in the past few years. Under the name of test suites for pairwise or combinatorial testing, they have proved very effective for testing hardware and software. This two-part mini-symposium showcases the interplay of covering array theory and applications. It shows how the applications motivated the study of generalizations of covering arrays with interesting ties to other areas of discrete mathematics (graph and hypergraph theory, graph homomorphisms, combinatorial group testing, probability theory). It also overviews current software testing research that supports the use of covering arrays. Tuesday May 31 15:15 - 15:40 Lucia Moura (University of Ottawa), Covering arrays and generalizations, MacLaurin D110 15:45 - 16:10 Elizabeth Maltais (University of Ottawa), Covering arrays avoiding forbidden edges, MacLaurin D110 16:15 - 16:40 Myra Cohen (University of Nebraska - Lincoln), GUI Interaction Testing: Using Covering Arrays to Provide Context in Software Testing, MacLaurin D110 16:45 - 17:10 Dan Hoffman (University of Victoria), The Influence of Parameter Values in the Practical Application of Combinatorial Test Generation, MacLaurin D110 17:15 - 17:40 Gary Bazdell (Carleton University), Evaluating Single Approach Constructions for Arbitrary Strength 2 Covering Arrays, MacLaurin D110 Covering Arrays, Generalizations and Software Testing Applications II (CM20) Org: Peter Danziger (Ryerson University), Lucia Moura (University of Ottawa) and Brett Stevens (Carleton University) Covering arrays are combinatorial designs that generalize orthogonal arrays, and have been more intensively studied in the past few years. Under the name of test suites for pairwise or combinatorial testing, they have proved very effective for testing hardware and software. This two-part mini-symposium showcases the interplay of covering array theory and applications. It shows how the applications motivated the study of generalizations of covering arrays with interesting ties to other areas of discrete mathematics (graph and hypergraph theory, graph homomorphisms, combinatorial group testing, probability theory). It also overviews current software testing research that supports the use of covering arrays. Thursday June 2 15:15 - 15:40 Anant Godbole (East Tennessee State University), Improving covering array bounds using alternative probability models, MacLaurin D110 15:45 - 16:10 Nevena Francetic (University of Toronto), Covering Arrays with Row Limit, MacLaurin D110 16:15 - 16:40 Brady Garvin (University of Nebraska -- Lincoln), Side Constraints and Covering Array Generation by Simulated Annealing, MacLaurin D110 16:45 - 17:10 Sebastian Raaphorst (University of Ottawa), Variable Strength Covering Arrays, MacLaurin D110 Designs and Codes I (CM13) Org: Peter Dukes (University of Victoria), Esther Lamken (California Institute of Technology) and John van Rees (University of Manitoba) Codes and Designs have many applications to statistics, communications and engineering. They are also an important component to pure mathematics, especially geometry. This mini-symposium plans to invite many of the top researchers in the field to present their latest results. We hope to have two sessions of 5 speakers each. Wednesday June 1 15:15 - 15:40 Doug Stinson (U. of Waterloo), A Unified Approach to Combinatorial Key Predistribution Schemes for Sensor Networks, MacLaurin D110 15:45 - 16:10 Clement Lam (Concordia University), A computer search for Projective Hjelmslev Planes of order 9, MacLaurin D110 16:15 - 16:40 Brett Stevens (Carleton University), Covering designs and Matroids, MacLaurin D110 16:45 - 17:10 Jeff Dinitz (University Of Vermont), Constructions for Retransmission Permutation Arrays, MacLaurin D110 17:15 - 17:40 John van Rees (U. of Manitoba), 3-Uniform Friendship Hypergraphs, MacLaurin D110 Designs and Codes II (CM16) Org: Peter Dukes (University of Victoria) This session is an extension of Designs and Codes I''. The focus is on combinatorial designs and error-correcting codes, with special emphasis on connections between those subjects. Thursday June 2 10:10 - 10:35 Peter Dukes (University of Victoria), Injection Codes, MacLaurin D110 10:40 - 11:05 Hadi Kharaghani (University of Lethbridge), The Gramian of mutually unbiased Hadamard matrices, MacLaurin D110 11:10 - 11:35 Esther Lamken (California Institute of Technology), Existence results for Howell cubes, MacLaurin D110 11:40 - 12:05 David Pike (Memorial University of Newfoundland), Hamilton cycles in restricted block-intersection graphs, MacLaurin D110 12:10 - 12:35 Alex Rosa (McMaster University), Circulants as signatures of cyclic Steiner triple systems, MacLaurin D110 Edge-Colouring and Structures on Line Graphs (CM5) Org: Jessica McDonald (Simon Fraser University) Different variations of edge-colourings are bound together by the structure of line graphs and the techniques that this structure suggests. Alternating paths play a vital role here, with current progress towards the famous Goldberg-Seymour Conjecture proceeding principally via the method of Tashkinov trees (a sophisticated selection of alternating paths). In this session we shall hear about such progress, as well as recent results on important variants of chromatic index, including circular chromatic index and acyclic list chromatic index. Tuesday May 31 15:15 - 15:40 Diego Scheide (Simon Fraser University), Acyclic list edge-colourings of degenerate graphs, Cornett A120 15:45 - 16:10 Andrew King (Columbia University), Bounding the chromatic index: Exploiting and sidestepping structure, Cornett A120 16:15 - 16:40 Oguz Kurt (The Ohio State University), The rule trees and the cubic root bound on the chromatic index, Cornett A120 16:45 - 17:10 Jessica McDonald (Simon Fraser University), Kempe equivalence of edge colourings in (sub)cubic graphs, Cornett A120 17:15 - 17:40 Luis Goddyn (Simon Fraser University), Edge List Colouring of Planar Cubic Graphs, Cornett A120 Embeddings and Geometric Representations of Graphs (CM1) Org: Debra Boutin (Hamilton College) This mini-symposium will explore the connections between abstract graphs and geometry (broadly defined). Some of the topics that naturally arise in this area are: interval graphs (vertices correspond to intervals of the real line, edges to intersecting intervals) or rectangle visibility graphs (vertices correspond to rectangles in the plane, edges to rectangle that can \lq\lq see" each other), geometric graphs (straightline drawings of graphs in the plane), graphs embedded on surfaces (edges don't cross and are not necessarily straight). Tuesday May 31 10:10 - 10:35 Dan Archdeacon (University of Vermont), The edge-ratio of geometric embeddings, Cornett A120 10:40 - 11:05 Andrew Beveridge (Macalester College), Directed Visibility Number for Planar Digraphs and Tournaments, Cornett A120 11:10 - 11:35 Sally Cockburn (Hamilton College), Permutations and Geometric Realizations of $K_{2,n}$, Cornett A120 11:40 - 12:05 Mark Ellingham (Vanderbilt University), Hamilton cycle embeddings of complete tripartite graphs, Cornett A120 12:10 - 12:35 Alice Dean (Skidmore College), Posets of Geometric Graphs, Cornett A120 Exact Combinatorics with Applications in Physics (CM7) Org: Marni MISHNA (Simon Fraser University) Physics is a rich source of inspiration for discrete mathematics. This minisymposium will focus on combinatorial work related to physics which is exact in nature rather than purely statistical. Such work can be quite varied both combinatorially and physically, but is unified in flavour and in the interplay of the fields. It is exciting because frequently not only does the physics inform the combinatorics, but also the combinatorics can be brought to bear nontrivially on interesting physical problems. Important examples include renormalization Hopf algebras in quantum field theory and exact enumeration of self avoiding walks in polymer physics. Wednesday June 1 10:10 - 10:35 Stu Whittington (University of Toronto), Directed walk models of polymers, Cornett A229 10:40 - 11:05 Karen Yeats (Simon Fraser University), Spanning forest polynomials and Feynman graph denominators, Cornett A229 11:10 - 11:35 Loic Foissy (Universite Reims), Systems of Dyson-Schwinger equations, Cornett A229 11:40 - 12:05 Chris Soteros (University of Saskatoon), Entanglement Complexity for Polygons in a Lattice Tube, Cornett A229 12:10 - 12:35 Philippe Nadeau (University of Vienna), Combinatorics of Fully Packed Loop configurations, Cornett A229 Finite Fields in Combinatorics I (CM2) Org: Daniel Panario (Carleton University) In this minisymposium, several topics of combinatorics where finite fields play an important role are presented. The talks show the use of finite fields to construct combinatorial objects and to prove interesting results in areas such as designs, graphs, latin squares, codes and sequences, finite geometries, among others. Tuesday May 31 10:10 - 10:35 Daniel Panario (Carleton University), Combinatorial Applications of Finite Fields, MacLaurin D110 10:40 - 11:05 Shonda Gosselin (University of Winnipeg), Paley uniform hypergraphs, MacLaurin D110 11:10 - 11:35 David Thomson (Carleton University), Sets of mutually orthogonal Latin hypercubes, MacLaurin D110 11:40 - 12:05 Petr Lisonek (Simon Fraser University), On the equivalence of quantum codes, MacLaurin D110 12:10 - 12:35 Tim Alderson (University of New Brunswick (Saint John)), Constructions of multiple wavelength codes ideal auto-correlation, MacLaurin D110 Finite Fields in Combinatorics II (CM8) Org: Daniel Panario (Carleton University) In this minisymposium, several topics of combinatorics where finite fields play an important role are presented. The talks show the use of finite fields to construct combinatorial objects and to prove interesting results in areas such as designs, graphs, latin squares, codes and sequences, finite geometries, among others. Wednesday June 1 10:10 - 10:35 Aiden Bruen (University of Calgary), Information sets and linear algebra, MacLaurin D110 10:40 - 11:05 Kai-Uwe Schmidt (Simon Fraser University), Sets of symmetric matrices over finite fields, MacLaurin D110 11:10 - 11:35 Qiang Wang (Carleton University), Ambiguity and Deficiency of Permutations, MacLaurin D110 11:40 - 12:05 Brett Stevens (Carleton University), finite field constructions of an imperfect design, MacLaurin D110 12:10 - 12:35 Sudhir Ghorpade (Indian Institute of Technology), Coprime polynomial pairs, Hankel matrices, and splitting subspaces, MacLaurin D110 Generalized Hadamard Matrices and Applications (CM21) Org: Aidan Roy and Ada Chan (University of Waterloo and York University) A {\em generalized Hadamard matrix} is a complex $n \times n$ matrix $H$ such that all entries of $H$ have the same absolute value, and $HH^* = nI$. Like real Hadamard matrices, generalized Hadamards often have interesting combinatorial properties and constructions. However, they also have a number of important applications. In quantum information theory, certain generalized Hadamards correspond to optimal tomographic measurements. In the theory of Type II matrices, they are closely connected to association schemes. In this minisymposium, we bring together people from various backgrounds to discuss the latest results and encourage communication between quantum information theorists and combinatorialists. Thursday June 2 15:15 - 15:40 Robert Craigen (University of Manitoba), Some Circulant Generalized Weighing matrices, MacLaurin D101 15:45 - 16:10 Aidan Roy (University of Waterloo), Generalized Hadamard matrices and quantum measurements, MacLaurin D101 16:15 - 16:40 Alyssa Sankey (University of New Brunswick), Type-II matrices associated with 2-graphs and weighted strongly regular graphs, MacLaurin D101 16:45 - 17:10 Hadi Kharaghani (University of Lethbridge), Mutually unbiased complex weighing matrices, MacLaurin D101 Geometric Representations of Graphs I (CM6) Org: Stefan Felsner (Technische Universitaet Berlin) Visualizations and representations of graphs by means of intersections or contacts of geometric objects have been widely investigated. Classical examples are interval graphs and Koebe circle representations. When representations are given they can sometimes be exploited in optimization problems. In many instances these problems are hard for general graphs but become polynomial-time solvable when restricted to intersection or contact graphs with a given representations. Another class of problems is to compute the representation or to decide whether it exists. In this minisymposium we highlight some recent developments in this active area at the intersection of graph theory and discrete geometry. Tuesday May 31 15:15 - 15:40 Matthew Francis (University of Toronto), On Segment graphs, Cornett A229 15:45 - 16:10 Jan Kratochvil (Charles University, Prague), Intersection graphs of homothetic polygons, Cornett A229 16:15 - 16:40 Tobias Müller (CWI, Amsterdam), The smallest grid needed to represent a geometric intersection graph, Cornett A229 16:45 - 17:10 Torsten Ueckerdt (Technische Universitaet Berlin), Edge-Intersection Graphs of Grid Paths - the Bend Number, Cornett A229 17:15 - 17:40 Sue Whitesides (University of Victoria, BC), On Upward Topological Book Embeddings of Upward Planar Digraphs, Cornett A229 Geometric Representations of Graphs II (CM9) Org: Jan Kratochvil (Charles University, Prague, Czech republic) Visualizations and representations of graphs by means of intersections or contacts of geometric objects have been widely investigated. Classical examples are interval graphs and Koebe circle representations. When representations are given they can sometimes be exploited in optimization problems. In many instances these problems are hard for general graphs but become polynomial-time solvable when restricted to intersection or contact graphs with a given representations. Another class of problems is to compute the representation or to decide whether it exists. In this minisymposium we highlight some recent developments in this active area at the intersection of graph theory and discrete geometry. Wednesday June 1 10:10 - 10:35 George Mertzios (University of Haifa, Israel), Geometric intersection models on the plane and the 3D-space, Cornett A120 10:40 - 11:05 Marcus Schaefer (DePaul University, Chicago, U.S.A.), Removing Monotone Crossings, Cornett A120 11:10 - 11:35 Daniel Gonçalves (LIRMM, Montpellier, France), Planar Graphs as Contact or Intersection Graphs of Homothetic Triangles, Cornett A120 11:40 - 12:05 Stefan Felsner (Technische Universitaet, Berlin, Germany), Graphs and Rectangle Dissections, Cornett A120 12:10 - 12:35 Anna Lubiw (University of Waterloo), Simultaneous Graph Representations, Cornett A120 Graph Searching (CM3) Org: Anthony Bonato (Ryerson University), Nancy Clarke (Acadia University) and Boting Yang (University of Regina) In graph searching a set of searchers pursue intruders in a two-player game played on a graph. The rules of the game may vary according to the capabilities of the players such as relative speed, sensor capabilities, or visibility. There has been much recent interest in graph searching, resulting in a wealth of structural, algorithmic, and probabilistic results. The main aim of the minisymposium (co-organized with Nancy Clarke and Boting Yang) is to bring together leading researchers in the field. The proposed speakers will cover such topics as Cops and Robbers and its variants, sweeping, graph cleaning, and firefighting. Tuesday May 31 10:10 - 10:35 Nancy Clarke (Acadia), Characterizations of $k$-copwin graphs, Cornett A229 10:40 - 11:05 Danny Dyer (Memorial), Fast searching graphs with few searchers, Cornett A229 11:10 - 11:35 Geňa Hahn (Montréal), Cops-and-robbers revisited, Cornett A229 11:40 - 12:05 Gary MacGillivray (Victoria), A characterization of infinite cop-win graphs, Cornett A229 12:10 - 12:35 Richard Nowakowski (Dalhousie), Cops and Robber with different edges sets, Cornett A229 Hypergraph Decompositions (CM23) Org: Shonda Gosselin (University of Winnipeg) This minisymposium showcases recent results involving hypergraph decompositions and their relation to combinatorial designs. We define and construct cyclic decompositions of complete uniform hypergraphs and complete multipartite hypergraphs, and examine their connection to both self-complementary graphs and large sets of designs. We also investigate covering and packing versions of Peter Cameron's generalized $t$-designs, which correspond to special coverings and packings of hypergraphs. Friday June 3 10:10 - 10:35 A. Pawel Wojda (AGH University of Science and Technology, Krakow, Poland.), Cyclic partitions of complete hypergraphs, MacLaurin D110 10:40 - 11:05 Mateja Sajna (University of Ottawa), Regular self-complementary uniform hypergraphs, MacLaurin D110 11:10 - 11:35 Shonda Gosselin (University of Winnipeg), Regular or vertex-transitive q-complementary hypergraphs, MacLaurin D110 11:40 - 12:05 Robert Bailey (University of Regina), Generalized covering designs as hypergraph covers, MacLaurin D110 12:10 - 12:35 Andrea Burgess (Ryerson University), Generalized packing designs and hypergraph packings, MacLaurin D110 Optimal Design of Experiments (CM14) Org: Julie Zhou (University of Victoria) The goal of this session is to bring together leading researchers in the areas of optimal design of experiments to exchange and discuss research ideas, and to encourage interactions between researchers in statistics and researchers in discrete mathematics. Research results in combinatorics and numerical algorithms are very useful to construct optimal designs. Five leading researchers in optimal design of experiments have tentatively agreed to give talks in this proposed session. Wednesday June 1 15:15 - 15:40 Ching-Shui Cheng (University of California, Berkeley), Optimal Block Designs and Graphs, MacLaurin D101 15:45 - 16:10 John Stufken (University of Goergia), Some combinatorial structures useful in design of experiments, MacLaurin D101 16:15 - 16:40 Boxin Tang (Simon Fraser University), Optimal Fractions of Two-level Factorials under a Baseline Parametrization, MacLaurin D101 16:45 - 17:10 Weng Kee Wong (University of California, Los Angeles), Algorithms for Generating Minimax Optimal Experimental Designs, MacLaurin D101 17:15 - 17:40 Jane Ye (University of Victoria), Minimizing the condition number to construct design points for polynomial regression models, MacLaurin D101 Spectral Graph Theory (CM17) Org: Bojan Mohar and Steve Kirkland (Simon Fraser University) Spectral graph theory is an important part of discrete mathematics with applications in many areas such as computer science, chemistry, network design and coding theory. One of the main goals of the theory is to deduce the principal properties of a graph from the spectral information furnished by one or more of the matrices associated with it. This minisymposium will showcase some of such connections and their applications. Thursday June 2 10:10 - 10:35 Bojan Mohar (Simon Fraser University), Spectrally degenerate graphs, Cornett A120 10:40 - 11:05 Sebastian Cioaba (University of California, San Diego), Eigenvalues and the structure of graphs., Cornett A120 11:10 - 11:35 Vlado Nikiforov (University of Memphis), The Ky Fan norms of graphs and matrices, Cornett A120 11:40 - 12:05 Steve Butler (University of California, Los Angeles), Forming graphs which are cospectral for the normalized Laplacian, Cornett A120 12:10 - 12:35 Azhvan Sheikh Ahmady (Simon Fraser University), Eigenvalues of graphs with many vertices of large degree, Cornett A120 Structured Graphs and Algorithms (CM10) Org: Jing Huang and Gary MacGillivray (University of Victoria) Combinatorial problems that are hard for general graphs are sometimes efficiently solvable for graphs belonging to classes like chordal, bi-arc, interval graphs, local tournaments, and the like. In some instances, for example the list homomorphism problem, it is precisely membership in such a class that distinguishes the polynomial and NP-complete instances of the problem. The speakers in this minisymposium will present results on the structure of graphs belonging to various special classes, and the complexity of combinatorial problems on such graphs. Wednesday June 1 10:10 - 10:35 Jorgen Bang-Jensen (University of Southern Denmark), Finding an induced subdivision of a digraph, Cornett A121 10:40 - 11:05 Ragnar Nevries (University of Rostock), Recognizing polar and monopolar graphs, Cornett A121 11:10 - 11:35 Ross Churchley (University of Victoria), Partitioning graphs via edge-coloured homomorphisms, Cornett A121 11:40 - 12:05 Mathew Francis (Charles University), Intersection dimensions of graphs, Cornett A121 12:10 - 12:35 Jing Huang (University of Victoria), Chronological interval digraphs, Cornett A121