
Please note that schedules are subject to change without notice, particularly changes within a given session.
Analytic and Probabilistic Techniques in Combinatorics  Part I (CM1)  
Org: Jan Volec (Emory University and Universitat Hamburg)  
Contemporary combinatorics is an exciting and rapidly growing discipline on the
frontier of mathematics and computer science. Many new techniques in
combinatorics rely on applications of tools from other mathematical areas such
as algebra, analysis and probability.
In the last decade, various novel methods have emerged. For example, recent works in the probabilistic method culminated with the celebrated container method which answered many longstanding open problems, new developments of algebraic techniques were crucial in settling famous conjectures in design theory or number theory, analytic approaches to Szemerédi's regularity lemma served as the cornerstone of graph limits, which then spinoff to techniques for large networks and development of flag algebras. In this minisymposium, we aim to bring researchers in combinatorics in order to present further developments and applications of these methods, and talk about completely new approaches. We will discuss relevant open problems, exchange research ideas, and initiate new collaborations.  
Thursday May 30  
10:30  10:50  Debsoumya Chakraborti (Carnegie Mellon University), Extremal Graphs With Local Covering Conditions, Canfor Policy Room 1600 
10:55  11:15  Joonkyung Lee (Universitat Hamburg), On triangulated common graphs, Canfor Policy Room 1600 
11:20  11:40  Jon Noel (University of Warwick), Cycles of length three and four in tournaments, Canfor Policy Room 1600 
11:45  12:05  Yanitsa Pehova (University of Warwick), Decomposing graphs into edges and triangles, Canfor Policy Room 1600 
12:10  12:30  Florian Pfender (University of Colorado Denver), 5Cycles in Graphs, Canfor Policy Room 1600 
Analytic and Probabilistic Techniques in Combinatorics  Part II (CM2)  
Org: Jan Volec (Emory University and Universitat Hamburg)  
Contemporary combinatorics is an exciting and rapidly growing discipline on the
frontier of mathematics and computer science. Many new techniques in
combinatorics rely on applications of tools from other mathematical areas such
as algebra, analysis and probability.
In the last decade, various novel methods have emerged. For example, recent works in the probabilistic method culminated with the celebrated container method which answered many longstanding open problems, new developments of algebraic techniques were crucial in settling famous conjectures in design theory or number theory, analytic approaches to Szemerédi's regularity lemma served as the cornerstone of graph limits, which then spinoff to techniques for large networks and development of flag algebras. In this minisymposium, we aim to bring researchers in combinatorics in order to present further developments and applications of these methods, and talk about completely new approaches. We will discuss relevant open problems, exchange research ideas, and initiate new collaborations.  
Thursday May 30  
15:30  15:50  Robert Hancock (Masaryk University), Some results in 1independent percolation, Canfor Policy Room 1600 
15:55  16:15  Guilherme Oliveira Mota (Universidade Federal do ABC), The multicolour sizeRamsey number of powers of paths, Canfor Policy Room 1600 
16:20  16:40  Robert Šámal (Charles University), A rainbow version of Mantel's Theorem, Canfor Policy Room 1600 
16:45  17:05  Maryam Sharifzadeh (University of Warwick), Graphons with minimum clique density, Canfor Policy Room 1600 
Average Graph Parameters  Part I (CM3)  
Org: Lucas Mol and Ortrud Oellermann (University of Winnipeg)  
Probably the oldest and most wellknown average graph parameter, the average distance of a graph  also known as the Wiener index, dates back to 1947. Of particular interest is the close correlation of the Wiener index of the molecular graph and the chemical properties of the substance such as the boiling point, viscosity and surface tension. In this minisymposium results on various average graph parameters such as the average distance in a digraph, the average order of subtrees of trees and some of its generalizations, as well as the average connectivity of graphs and digraphs are presented.  
Thursday May 30  
10:30  10:50  Lucas Mol (University of Winnipeg), The Mean Subtree Order and the Mean Connected Induced Subgraph Order, Sauder Industries Policy Room 2270 
10:55  11:15  Stephan Wagner (Stellenbosch University), Extremal subtree densities of trees, Sauder Industries Policy Room 2270 
11:20  11:40  Hua Wang (Georgia Southern University), Average distance between leaves and peripheral vertices, Sauder Industries Policy Room 2270 
11:45  12:05  Pengyu Liu (Simon Fraser University), A polynomial metric on rooted binary tree shapes, Sauder Industries Policy Room 2270 
Average Graph Parameters  Part II (CM4)  
Org: Lucas Mol and Ortrud Oellermann (University of Winnipeg)  
Probably the oldest and most wellknown average graph parameter, the average distance of a graph  also known as the Wiener index, dates back to 1947. Of particular interest is the close correlation of the Wiener index of the molecular graph and the chemical properties of the substance such as the boiling point, viscosity and surface tension. In this minisymposium results on various average graph parameters such as the average distance in a digraph, the average order of subtrees of trees and some of its generalizations, as well as the average connectivity of graphs and digraphs are presented.  
Thursday May 30  
15:30  15:50  Stijn Cambie (Radboud University), Asymptotic resolution of a question of Plesník, Sauder Industries Policy Room 2270 
15:55  16:15  Peter Dankelmann (University of Johannesburg), The average distance of maximal planar graphs, Sauder Industries Policy Room 2270 
16:20  16:40  Suil O (State University of New York, Korea), Average connectivity and average edgeconnectivity in graphs, Sauder Industries Policy Room 2270 
16:45  17:05  Ortrud Oellermann (University of Winnipeg), The average connectivity of minimally $2$connected graphs, Sauder Industries Policy Room 2270 
Bootstrap Percolation (CM5)  
Org: Natasha Morrison (Instituto National de Matemática Pura e Aplicada) and Jonathan Noel (University of Warwick)  
Bootstrap percolation is a process on graphs which models real world phenomena including the dynamics of ferromagnetism and the spread of opinions in a social network. Topics covered in this minisymposium include recent breakthroughs on old and difficult problems alongside some of the most exciting new research directions in the area.  
Tuesday May 28  
15:30  15:50  Janko Gravner (University of California, Davis), Polluted Bootstrap Percolation, McCarthy Tetrault Lecture Room 2245 
15:55  16:15  Lianna Hambardzumyan (McGill University), Polynomial method and graph bootstrap percolation, McCarthy Tetrault Lecture Room 2245 
16:20  16:40  David Sivakoff (The Ohio State University), Bootstrap percolation on Cartesian products of lattices with Hamming graphs, McCarthy Tetrault Lecture Room 2245 
16:45  17:05  Ivailo Hartarsky (École normale supérieure de Lyon), The second term for twoneighbour bootstrap percolation in two dimensions, McCarthy Tetrault Lecture Room 2245 
Colourings and homomorphisms (CM6)  
Org: Gary MacGillivray (University of Victoria)  
The talks focus on aspects of graph colouring and homomorphisms including fractional colourings, oriented colourings, geometric homomorphisms and reconfiguration problems.  
Thursday May 30  
10:30  10:50  Debra Boutin (Hamilton College), Geometric Homomorphisms and the Geochromatic Number, Scotiabank Lecture Room 1315 
10:55  11:15  Richard Brewster (Thompson Rivers University), The complexity of signed graph homomorhpisms, Scotiabank Lecture Room 1315 
11:20  11:40  Christopher Duffy (University of Saskatchewan), Colourings, Simple Colourings, and a Connection to Bootstrap Percolation, Scotiabank Lecture Room 1315 
11:45  12:05  John Gimbel (University of Alaska), Bounds on the fractional chromatic number of a graph., Scotiabank Lecture Room 1315 
12:10  12:30  JaeBaek Lee (Kyungpook National University), Reconfiguring Reflexive Digraphs, Scotiabank Lecture Room 1315 
Covering Arrays  Part I (CM7)  
Org: Lucia Moura (University of Ottawa) and Brett Stevens (Carleton University)  
A covering array with $N$ rows, $k$ columns, $v$ symbols and strength $t$ is an $N \times k$ array with entries from a $v$ary alphabet such that each of its subarrays with $t$ columns contains every $t$tuple of the alphabet at least once as a row. Covering arrays have gained a lot of attention in the theory of combinatorial designs and in applications to software and network testing. Classical covering arrays and their many generalizations have interesting relations to areas of combinatorics such as extremal set theory, finite fields, graph homomorphisms, covering codes and combinatorial group testing. Methods for their construction range from recursive and algebraic to probabilistic and computational. In this twopart minisymposium, we have a collection of talks highlighting current research on various aspects of covering arrays.  
Friday May 31  
10:30  10:50  Brett Stevens (Carleton University), Introduction to covering arrays, Canfor Policy Room 1600 
10:55  11:15  Yasmeen Akhtar (Arizona State University, USA), Constructing High Index Covering Arrays and Their Application to Design of Experiments, Canfor Policy Room 1600 
11:20  11:40  Kirsten Nelson (Carleton University), Constructing covering arrays from interleaved sequences, Canfor Policy Room 1600 
11:45  12:05  Myra B. Cohen (Iowa State University), Learning to Build Covering Arrays with Hyperheuristic Search, Canfor Policy Room 1600 
Covering Arrays  Part II (CM8)  
Org: Lucia Moura (University of Ottawa) and Brett Stevens (Carleton University)  
A covering array with $N$ rows, $k$ columns, $v$ symbols and strength $t$ is an $N\times k$ array with entries from a $v$ary alphabet such that each of its subarrays with $t$ columns contains every $t$tuple of the alphabet at least once as a row. Covering arrays have gained a lot of attention in the theory of combinatorial designs and in applications to software and network testing. Classical covering arrays and their many generalizations have interesting relations to areas of combinatorics such as extremal set theory, finite fields, graph homomorphisms, covering codes and combinatorial group testing. Methods for their construction range from recursive and algebraic to probabilistic and computational. In this twopart minisymposium, we have a collection of talks highlighting current research on various aspects of covering arrays.  
Friday May 31  
15:30  15:50  Lucia Moura (University of Ottawa), Getting hyper with covering arrays, Canfor Policy Room 1600 
15:55  16:15  Anant Godbole (East Tennessee State University, USA), Covering Arrays for Some Equivalence Classes of Words, Canfor Policy Room 1600 
16:20  16:40  Muhammad Javed (Ryerson University), Sequence Covering Arrays, Canfor Policy Room 1600 
16:45  17:05  André Castoldi (Universidade Tecnológica Federal do Paraná, Brazil), Bounds on Covering Codes in RosenbloomTsfasman Spaces using Ordered Covering Arrays, Canfor Policy Room 1600 
Design Theory  Part I (CM9)  
Org: Andrea Burgess (University of New Brunswick), Peter Danziger (Ryerson University) and David Pike (Memorial University of Newfoundland)  
2019 marks the 175th anniversary of the birth of F\'{e}lix Walecki, who did pioneering work in design theory, particularly in factorizations and cycle decompositions of the complete graph. In addition to celebrating this event, this minisymposium brings together leading and emerging researchers in combinatorial design theory to share their results pertaining to designs and related structures, their properties and applications.  
Wednesday May 29  
15:30  15:50  Esther Lamken (California Institute of Technology), Constructions and uses of incomplete pairwise balanced designs, Canadian Pacific Lecture Room 1530 
15:55  16:15  Peter Dukes (University of Victoria), Packings of 4cliques in complete graphs, Canadian Pacific Lecture Room 1530 
16:20  16:40  Flora Bowditch (University of Victoria), Localized Structure in Graph Decompositions, Canadian Pacific Lecture Room 1530 
16:45  17:05  Iren Darijani (Memorial University of Newfoundland), kcolourings of star systems, Canadian Pacific Lecture Room 1530 
Design Theory  Part II (CM10)  
Org: Andrea Burgess (University of New Brunswick), Peter Danziger (Ryerson University) and David Pike (Memorial University of Newfoundland)  
2019 marks the 175th anniversary of the birth of F\'{e}lix Walecki, who did pioneering work in design theory, particularly in factorizations and cycle decompositions of the complete graph. In addition to celebrating this event, this minisymposium brings together leading and emerging researchers in combinatorial design theory to share their results pertaining to designs and related structures, their properties and applications.  
Thursday May 30  
10:30  10:50  Marco Buratti (Università degli Studi di Perugia), Cyclic designs: some selected topics, McLean Management Studies Lab 2945 
10:55  11:15  Saad ElZanati (Illinois State University), On edge orbits and hypergraph designs, McLean Management Studies Lab 2945 
11:20  11:40  Francesca Merola (Università Roma Tre), Cycle systems of the complete multipartite graph, McLean Management Studies Lab 2945 
11:45  12:05  Mateja Sajna (University of Ottawa), On the Honeymoon Oberwolfach Problem, McLean Management Studies Lab 2945 
12:10  12:30  Sibel Ozkan (Gebze Technical University), On The HamiltonWaterloo Problem and its Generalizations, McLean Management Studies Lab 2945 
Design Theory  Part III (CM11)  
Org: Andrea Burgess (University of New Brunswick), Peter Danziger (Ryerson University) and David Pike (Memorial University of Newfoundland)  
2019 marks the 175th anniversary of the birth of F\'{e}lix Walecki, who did pioneering work in design theory, particularly in factorizations and cycle decompositions of the complete graph. In addition to celebrating this event, this minisymposium brings together leading and emerging researchers in combinatorial design theory to share their results pertaining to designs and related structures, their properties and applications.  
Thursday May 30  
15:30  15:50  Doug Stinson (University of Waterloo), Constructions of optimal orthogonal arrays with repeated rows, McLean Management Studies Lab 2945 
15:55  16:15  Brett Stevens (Carleton University), Affine planes with ovals for blocks, McLean Management Studies Lab 2945 
16:20  16:40  Trent Marbach (Nankai University), Balanced Equinsquares, McLean Management Studies Lab 2945 
16:45  17:05  Hadi Kharighani (University of Lethbridge), Unbiased Orthogonal Designs, McLean Management Studies Lab 2945 
Elegant and Discrete Mathematics (CM12)  
Org: Karen Meagher (University of Regina)  
Discrete math is famous for being an area of mathematics where the problems are easy to state, but difficult to prove. This session will focus on results where the problems are easy to state, but the solutions are surprisingly elegant and give deeper insight into the mathematics behind the problem.
The speakers will each describe an elegant new result in their field. The talks will focus on key ideas in the proofs and the intriguing aspects of their results. The goal is to offer some entry points into modern algebraic combinatorics, enumerative combinatorics, graph theory, and extremal set theory.  
Tuesday May 28  
15:30  15:50  Karen Meagher (University of Regina), All 2transitive groups have the ErdosKoRado Property, McLean Management Studies Lab 2945 
15:55  16:15  Marni Mishna (Simon Fraser University), On the complexity of the cogrowth sequence, McLean Management Studies Lab 2945 
16:20  16:40  Jessica Striker (North Dakota State University), Bijections  Marvelous, Mysterious, and Missing, McLean Management Studies Lab 2945 
16:45  17:05  Steph van Willigenburg (Univeristy of British Columbia), The positivity of trees, McLean Management Studies Lab 2945 
17:10  17:30  Hanmeng (Harmony) Zhan (Université de Montréal), Some elegant results in algebraic graph theory, McLean Management Studies Lab 2945 
Finite Fields in Discrete Mathematics  Part I (CM13)  
Org: Petr Lisonek (Simon Fraser University) and Daniel Panario (Carleton University)  
In this minisymposium several topics in discrete mathematics 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, cryptography, Boolean functions, codes and sequences, algebraic curves and finite geometries, among others.  
Friday May 31  
10:30  10:50  Daniel Panario (Carleton University), Finite Fields in Discrete Mathematics, Sauder Industries Policy Room 2270 
10:55  11:15  Thais Bardini Idalino (University of Ottawa), Embedding coverfree families and cryptographical applications, Sauder Industries Policy Room 2270 
11:20  11:40  Daniele Bartoli (University of Perugia), More on exceptional scattered polynomials, Sauder Industries Policy Room 2270 
11:45  12:05  Claudio Qureshi (University of Campinas), Dynamics of Chebyshev polynomials over finite fields, Sauder Industries Policy Room 2270 
12:10  12:30  Anne Canteaut (Inria Paris), Searching for APN permutations with the butterfly construction, Sauder Industries Policy Room 2270 
Finite Fields in Discrete Mathematics  Part II (CM14)  
Org: Petr Lisonek (Simon Fraser University) and Daniel Panario (Carleton University)  
In this minisymposium several topics in discrete mathematics 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, cryptography, Boolean functions, codes and sequences, algebraic curves and finite geometries, among others.  
Friday May 31  
15:30  15:50  Sihem Mesnager (University of Paris VIII), On good polynomials over finite fields for optimal locally recoverable codes, Sauder Industries Policy Room 2270 
15:55  16:15  Lucas Reis (University of Sao Paulo), Permutations of finite sets from an arithmetic setting, Sauder Industries Policy Room 2270 
16:20  16:40  Daniel Katz (California State University, Northridge), Nonvanishing minors and uncertainty principles for Fourier analysis over finite fields, Sauder Industries Policy Room 2270 
16:45  17:05  Ariane Masuda (City University of New York), Functional Graphs of R\'edei Functions, Sauder Industries Policy Room 2270 
17:10  17:30  Petr Lisonek (Simon Fraser University), Maximally nonassociative quasigroups, Sauder Industries Policy Room 2270 
Finite Geometries and Applications (CM15)  
Org: Sam Mattheus (Vrije Universiteit Brussel)  
Finite geometries is the research field in which finite incidence structures, often defined over finite fields, are investigated. Among the structures of interest are vector spaces and projective spaces, generalized polygons and others. The study of these structures and their substructures is the central topic in this area for several reasons. Plenty of these substructures are investigated for their intrinsic importance and interest, others are investigated because of their relation to other research areas such as coding theory, graph theory and even number theory. In this symposium we will have a mix of both, presenting purely geometrical problems, graph theoretical problems with geometrical roots, applications to coding theory and even an application in number theory over finite fields.  
Tuesday May 28  
10:30  10:50  Sam Mattheus (Vrije Universiteit Brussel), Number theory in finite fields from a geometrical point of view, Cominco Policy Room 1415 
10:55  11:15  Jozefien D'haeseleer (Universiteit Gent), Projective solids pairwise intersecting in at least a line, Cominco Policy Room 1415 
11:20  11:40  Jan De Beule (Vrije Universiteit Brussel), A lower bound on the size of linear sets on a projective line of finite order, Cominco Policy Room 1415 
11:45  12:05  Lins Denaux (Universiteit Gent), Small weight code words in the code of points and hyperplanes of PG(n,q), Cominco Policy Room 1415 
12:10  12:30  Lisa Hernandez Lucas (Vrije Universiteit Brussel), Dominating sets in finite generalized quadrangles, Cominco Policy Room 1415 
Graph Polynomials  Part I (CM16)  
Org: Danielle Cox (Mount Saint Vincent University) and Christopher Duffy (University of Saskatchewan)  
Polynomials are powerful mathematical models. Many combinatorial sequences can be investigated via their associated generating polynomial. The study of graph polynomials can be found in the literature of many combinatorial problems. For instance, one can investigate combinatorial sequences associated with graph properties, such as independence or domination by looking at the analytic properties of the associated generating polynomial. Other combinatorial problems, such as network reliability and graph colouring are modelled using polynomials. This two part minisymposium will highlight interesting new results related to the study of graph polynomials.  
Tuesday May 28  
10:30  10:50  Iain Beaton (Dalhousie University), Independence Equivalence Class of Paths and Cycles, Canfor Policy Room 1600 
10:55  11:15  Ben Cameron (Dalhousie University), The Maximum Modulus of an Independence Root, Canfor Policy Room 1600 
11:20  11:40  Mackenzie Wheeler (University of Victorica), Chromatic Uniqueness of Mixed Graphs, Canfor Policy Room 1600 
11:45  12:05  Lucas Mol (University of Winnipeg), The Subtree Polynomial, Canfor Policy Room 1600 
12:10  12:30  Lise Turner (University of Waterloo), Convergence of Coefficients of the Rank Polynomial in BenjaminiSchramm Convergent Sequences of Graphs, Canfor Policy Room 1600 
Graph Polynomials  Part II (CM17)  
Org: Danielle Cox (Mount Saint Vincent Universityx) and Christopher Duffy (Christopher Duffy)  
Polynomials are powerful mathematical models. Many combinatorial sequences can be investigated via their associated generating polynomial. The study of graph polynomials can be found in the literature of many combinatorial problems. For instance, one can investigate combinatorial sequences associated with graph properties, such as independence or domination by looking at the analytic properties of the associated generating polynomial. Other combinatorial problems, such as network reliability and graph colouring are modelled using polynomials. This two part minisymposium will highlight interesting new results related to the study of graph polynomials.  
Tuesday May 28  
15:30  15:50  David Wagner (University of Waterloo), Ursell inequalities for random spanning trees, Canfor Policy Room 1600 
15:55  16:15  Christopher Duffy (University of Saskatchewan), The Oriented Chromatic Polynomial, Canfor Policy Room 1600 
16:20  16:40  Nicholas Harvey (University of British Columbia), Computing the Independence Polynomial in Shearer's Region for the Lovasz Local Lemma, Canfor Policy Room 1600 
16:45  17:05  Danielle Cox (Mount Saint Vincent University), Optimal Graphs for Domination Polynomials, Canfor Policy Room 1600 
Graph Searching Games  Part I (CM18)  
Org: Anthony Bonato (Ryerson University) and Danielle Cox (Mount Saint Vincent University)  
In graph searching games such as Cops and Robbers, agents must capture or slow an intruder loose on a network. The rules of the game dictate how the players move and how capture occurs. The associated optimization parameter in Cops and Robbers is the cop number, which measures how many cops are needed for a guaranteed capture. The study of the cop number has lead to a number of unsolved problems, ranging from Meyniel's conjecture to Schroeder's conjecture on graphs with bounded genus. Cops and Robbers is only one graph searching game among many others, and graph searching intersects with algorithmic, structural, and probabilistic graph theory. Other recent graph searching games and processes that have generated interest are Zombies and Survivors, localization, graph burning, and Firefighting.
The proposed minisymposium brings together leading researchers in graph searching, who will present stateoftheart research in this direction.  
Wednesday May 29  
10:30  10:50  Anthony Bonato (Ryerson University), Bounds and algorithms for graph burning, Sauder Industries Policy Room 2270 
10:55  11:15  Nancy Clarke (Acadia University), $\ell$Visibility Cops and Robber, Sauder Industries Policy Room 2270 
11:20  11:40  Sean English (Ryerson University), Catching Robbers Quickly and Efficiently, Sauder Industries Policy Room 2270 
11:45  12:05  Natasha Komarov (St. Lawrence University), Containing a robber on a graph, Sauder Industries Policy Room 2270 
Graph Searching Games  Part II (CM19)  
Org: Anthony Bonato (Ryerson University) and Danielle Cox (Mount Saint Vincent University)  
In graph searching games such as Cops and Robbers, agents must capture or slow an intruder loose on a network. The rules of the game dictate how the players move and how capture occurs. The associated optimization parameter in Cops and Robbers is the cop number, which measures how many cops are needed for a guaranteed capture. The study of the cop number has lead to a number of unsolved problems, ranging from Meyniel's conjecture to Schroeder's conjecture on graphs with bounded genus. Cops and Robbers is only one graph searching game among many others, and graph searching intersects with algorithmic, structural, and probabilistic graph theory. Other recent graph searching games and processes that have generated interest are Zombies and Survivors, localization, graph burning, and Firefighting.
The proposed minisymposium brings together leading researchers in graph searching, who will present stateoftheart research in this direction.  
Wednesday May 29  
15:30  15:50  Bill Kinnersley (University of Rhode Island), Cops and Lawless Robbers, Sauder Industries Policy Room 2270 
15:55  16:15  Kerry Ojakian (Bronx Community College (C.U.N.Y.)), Graphs that are copwin, but not zombiewin, Sauder Industries Policy Room 2270 
16:20  16:40  Pawel Pralat (Ryerson University), Zero Forcing Number of Random Regular Graphs, Sauder Industries Policy Room 2270 
16:45  17:05  Ladislav Stacho (Simon Fraser University), Efficient Periodic Graph Traversal on Graphs with a Given Rotation System, Sauder Industries Policy Room 2270 
Graph Structure and Algorithms (CM20)  
Org: Kathie Cameron (Wilfrid Laurer University) and Shenwei Huang (Nankai University)  
Graph algorithms are at the core of discrete mathematics and computer science. They play an increasingly critical role in fundamental research as well as real applications. In this minisymposium, we will hear a variety of exciting developments on complexity of graph problems such as colouring, $\chi$bounds, clique minors, and hamiltonian cycles, and on structure of important classes of graphs and digraphs.  
Friday May 31  
10:30  10:50  Kathie Cameron (Wilfrid Laurer University), Hadwiger's Conjecture for (Cap, Even Hole)Free Graphs, Cominco Policy Room 1415 
10:55  11:15  Owen Merkel (University of Waterloo), An optimal $\chi$Bound for ($P_6$, diamond)free graphs, Cominco Policy Room 1415 
11:20  11:40  Juraj Stacho (Google Zurich), 3colorable Subclasses of $P_8$free Graphs, Cominco Policy Room 1415 
11:45  12:05  César Hernández Cruz (CINVESTAV Mexico), On the Pancyclicity of $k$quasitransitive Digraphs ofLlarge Diameter, Cominco Policy Room 1415 
12:10  12:30  Pavol Hell (Simon Fraser University), Bipartite Analogues of Comparability and Cocomparability Graphs, Cominco Policy Room 1415 
Matching Theory (CM21)  
Org: Nishad Kothari (University of Campinas)  
Matching Theory pertains to the study of perfect matchings in graphs. It is one of the oldest branches of graph theory that finds many applications in combinatorial optimization, and that continues to inspire new results. For several problems in Matching Theory, such as counting the number of perfect matchings, one may restrict attention to `matching covered' or `1extendable' graphs  connected graphs in which each edge lies in some perfect matching. Lov\'asz and Plummer (1986) provide a comprehensive treatment of the subject in their book ``Matching Theory''. Since then, a lot more work has been done to further our understanding of the structure of $1$extendable graphs, as well as their generalization `$k$extendable' graphs  connected graphs in which every matching of size $k$ may be extended to a perfect matching. In this minisymposium, we shall cover some of the recent developments in this beautiful area that continues to blossom.  
Wednesday May 29  
10:30  10:50  Marcelo Carvalho (Federal University of Mato Grosso do Sul (UFMS)), Birkhoffvon Neumann Graphs that are PMcompact, McCarthy Tetrault Lecture Room 2245 
10:55  11:15  Nishad Kothari (University of Campinas (UNICAMP)), Constructing $K_4$free bricks that are Pfaffian, McCarthy Tetrault Lecture Room 2245 
11:20  11:40  Phelipe Fabres (Federal University of Mato Grosso do Sul (UFMS)), Minimal Braces, McCarthy Tetrault Lecture Room 2245 
11:45  12:05  Michael Plummer (Vanderbilt University), Distance Matching in Planar Triangulations: some new results, McCarthy Tetrault Lecture Room 2245 
12:10  12:30  Robert Aldred (University of Otago), Asymmetric Distance Matching Extension, McCarthy Tetrault Lecture Room 2245 
Minisymposium in honor of Frank Ruskey's 65th birthday (CM22)  
Org: Torsten Mütze (TU Berlin) and Joe Sawada (University of Guelph)  
Frank Ruskey turned 65 last year, and the goal of this minisymposium is to honor his scientific achievements in discrete mathematics and theoretical computer science, by bringing together collaborators, colleagues, academic descendants and friends on this occasion. The talks center around combinatorial algorithms, Gray codes, Venn diagrams, and other discrete topics that are close to Frank's own contributions.  
Tuesday May 28  
10:30  10:50  Joe Sawada (University of Guelph), From 3/30 on Frank's midterm to a career in Academia, Sauder Industries Policy Room 2270 
10:55  11:15  Gary MacGillivray (University of Victoria), Using combinatorial algorithms to search for golf schedules, Sauder Industries Policy Room 2270 
11:20  11:40  Alejandro Erickson (University of Victoria), Tatami Tilings in a Template for Teaching to Teenagers, Sauder Industries Policy Room 2270 
11:45  12:05  Gara Pruesse (Vancouver Island University), Linear Extensions of Posets  Gray codes, fast generation algorithms, and a longstanding conjecture, Sauder Industries Policy Room 2270 
12:10  12:30  Torsten Mütze (TU Berlin), Combinatorial generation via permutation languages, Sauder Industries Policy Room 2270 
Optimization, Geometry and Graphs (CM23)  
Org: Bruce Shepherd (UBC)  
This session links topics in optimization arising in geometric and graphical settings.  
Tuesday May 28  
10:30  10:50  Coulter Beeson (UBC), Revisiting the Core of Papadimitriou's MultiFlow Game, Scotiabank Lecture Room 1315 
10:55  11:15  Will Evans (UBC), Minimizing Interference Potential Among Moving Entities, Scotiabank Lecture Room 1315 
11:20  11:40  David Hartvigsen (Notre Dame), Finding Trianglefree 2factors, Revisited, Scotiabank Lecture Room 1315 
11:45  12:05  Venkatesh Srinivasan (UBC), Scalable Misinformation Prevention in Social Networks, Scotiabank Lecture Room 1315 
12:10  12:30  Tamon Stephen (SFU), On the Circuit Diameter Conjecture, Scotiabank Lecture Room 1315 
Structured families of graphs and digraphs: characterizations, algorithms and partition problems (CM24)  
Org: César HernándezCruz (CINVESTAV, Mexico)  
There are many graph and digraph families that can be characterized
by forbidding the existence of certain substructures, e.g., induced
subgraphs or minors. Two main questions naturally arise for these
families: Can they be recognized efficiently? Is the characterization
useful to solve hard problems efficiently in these classes?
This session is devoted to the study of such graph and digraph families, their characterization theorems, and how their structure is useful to solve, or approximate, vertex partition problems (colourings, homomorphisms, vertex arboricity) efficiently.  
Friday May 31  
15:30  15:50  Sebastián González Hermosillo de la Maza (Simon Fraser University), Arboricity and feedbacks sets in cographs, Fletcher Challenge Theatre 1900 
15:55  16:15  Seyyed Aliasghar Hosseini (Simon Fraser University), The evolution of the structure of ABCminimal trees, Fletcher Challenge Theatre 1900 
16:20  16:40  Jing Huang (University of Victoria), Graph and digraph classes arising from list homomorphism problems, Fletcher Challenge Theatre 1900 
16:45  17:05  Mahdieh Malekian (Simon Fraser University), The structure of graphs with no $H$immersion, Fletcher Challenge Theatre 1900 
Symmetry in Graphs  Part I (CM25)  
Org: Joy Morris (University of Lethbridge)  
Symmetry in graphs has both beauty and practical implications, and typically involves the actions of permutation groups on the vertices and/or on the edges. This minisymposium will explore recent work on symmetry in graphs. Talks will emphasise situations where symmetries are limited in some way (for example, removing symmetries by colouring vertices or edges, or studying graphs that only admit specified symmetries). This is part 1 of 2.  
Wednesday May 29  
10:30  10:50  Debra Boutin (Hamilton College), New Techniques in the Cost of 2Distinguishing Hypercubes, Canfor Policy Room 1600 
10:55  11:15  Karen Collins (Wesleyan University), The distinguishing number of posets and lattices, Canfor Policy Room 1600 
11:20  11:40  Richard Hammack (Virginia Commonwealth University), Edgetransitive direct products of graphs, Canfor Policy Room 1600 
11:45  12:05  Bohdan Kivva (University of Chicago), Minimal degree of the automorphism group of primitive coherent configurations, Canfor Policy Room 1600 
12:10  12:30  Florian Lehner (University of Warwick), On symmetries of vertex and edge colourings of graphs, Canfor Policy Room 1600 
Symmetry in Graphs  Part II (CM26)  
Org: Joy Morris (University of Lethbridge)  
Symmetry in graphs has both beauty and practical implications, and typically involves the actions of permutation groups on the vertices and/or on the edges. This minisymposium will explore recent work on symmetry in graphs. Talks will emphasise situations where symmetries are limited in some way (for example, removing symmetries by colouring vertices or edges, or studying graphs that only admit specified symmetries). This is part 2 of 2.  
Wednesday May 29  
15:30  15:50  Michael Giudici (University of Western Australia), Arctransitive bicirculants, Canfor Policy Room 1600 
15:55  16:15  Klavdija Kutnar (University of Primorska), Hamilton paths of cubic vertextransitive graphs, Canfor Policy Room 1600 
16:20  16:40  Joy Morris (University of Lethbridge), Almost all Cayley digraphs are DRRs, Canfor Policy Room 1600 
16:45  17:05  Gabriel Verret (University of Auckland), An update on the Polycirculant Conjecture, Canfor Policy Room 1600 