Algebraic graph theory in quantum computing Org: Ada Chan (York University) Quantum walks are an important concept in the study of quantum algorithms. Quantum walk algorithms have been studied and shown to perform exponentially or polynomially better for various black box problems. Problems about quantum walks on graphs have also produced numerous interesting mathematical problems, where techniques in algebraic graph theory have yielded new advances. This minisymposium will give an overview of recent work along this vein, as well as encourage further collaboration. Other organizers: Chris Godsil (University of Waterloo), Krystal Guo (University of Waterloo), and Christino Tamon (Clarkson University) Thursday June 15 15:20 - 15:45 Luc Vinet (University of Montreal), NEXT-TO-NEAREST NEIGHBOUR COUPLINGS AND ENTANGLEMENT GENERATION IN SPIN CHAINS AND OPTICAL ARRAYS 15:50 - 16:15 Christopher van Bommel (University of Waterloo), Characterizing Pretty Good State Transfer on Paths 16:20 - 16:45 Mark Kempton (Harvard University), Quantum state transfer on graphs 16:50 - 17:15 Thomas Wong (University of Texas at Austin), Degenerate Perturbation Theory as a Tool for Quantum Search 17:20 - 17:45 Harmony Zhan (University of Waterloo), Discrete-Time Quantum Walks and Graph Structures Average Graph Parameters I Org: Ortrud Oellermann and Lucas Mol (University of Winnipeg) Probably the oldest and most well-known 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 reliability of a graph and their relationships with the structural properties of the (di)graph are presented. Monday June 12 15:20 - 15:45 Danielle Cox (Mount Saint Vincent University), The Average Reliability of a Graph 15:50 - 16:15 Peter Dankelmann (University of Johannesburg), Bounds on the average distance of directed graphs 16:20 - 16:45 Lucas Mol (University of Winnipeg), Maximizing mean subtree order for classes of trees 16:50 - 17:15 Ortrud Oellermann (University of Winnipeg), On the mean order of sub-$k$-trees of $k$-trees 17:20 - 17:45 Hua Wang (Georgia Southern University), On the average subtree order of trees and related studies Combinatorial Gray codes Org: Jan Goedgebeur (Ghent University) and Torsten MÃ¼tze (TU Berlin) Generating all the objects in a particular class (e.g. permutations, subsets, strings, trees, graphs etc.) such that each object is generated exactly once is one of the oldest and most basic combinatorial problems, with a large number of practical applications. In fact, more than half of Donald Knuth's most recent book in the seminal series 'The Art of Computer Programming' is entirely devoted to this fundamental subject. This minisymposium aims at presenting some of the exciting recent developments in the area of combinatorial Gray codes, and to circulate challenging open problems among researchers in the field. This minisymposium has a companion entitled Computational combinatorics' in which such generation algorithms have been applied successfully to solve various combinatorial problems. Monday June 12 10:20 - 10:45 Aaron Williams (Bard College at Simon's Rock), The Twelvefold Way with Greedy Gray Codes 10:50 - 11:15 Dennis Wong (Northwest Missouri State University), Induced 2-Gray codes inside the Binary Reflected Gray Code 11:20 - 11:45 Joe Sawada (University of Guelph), New and simple de Bruijn sequence constructions 11:50 - 12:15 Torsten MÃ¼tze (TU Berlin), Trimming and gluing Gray codes Combinatorial Optimization Org: Guyslain Naves (Aix-Marseille University) and Bruce Shepherd (McGill) Min-max results (exact and approximate) and new models in combinatorial optimization arising from flows, cuts, and matroids. Monday June 12 15:20 - 15:45 Ahmad Abdi (Waterloo), Ideal clutters that do not pack 15:50 - 16:15 Andras Frank (Eotvos Lorand University), Finding $k$ disjoint branchings with specified sizes 16:20 - 16:45 Vivek Madan (Uuniversity Illininois Urbana-Champaign), Revisiting Cut problems and Labelling LPs 16:50 - 17:15 Richard Santiago (McGill University), Multi-agent Submodular Optimization 17:20 - 17:45 Bruce Shepherd (McGill University), Conflict-Free Disjoint Paths and Stable Matchings Computational combinatorics Org: Jan Goedgebeur (Ghent University) and Torsten MÃ¼tze (TU Berlin) Computers are often used in combinatorics to determine if combinatorial objects with given structural or extremal properties exist as these existence problems are often too complex to solve by hand. This is done by designing and implementing generation algorithms which construct combinatorial objects from a given class (typically avoiding the generation of isomorphic copies). This minisymposium presents some recent examples where computers have been successfully used to solve problems in graph colouring, Hamiltonicity and Ramsey theory. This minisymposium has a companion entitled Combinatorial Gray codes', covering algorithms for generating various families of combinatorial objects, which are an essential tool for such exhaustive enumeration approaches. Tuesday June 13 15:20 - 15:45 Richard Brewster (Thompson Rivers University), Computational examples for aiding graph theory research 15:50 - 16:15 Jan Goedgebeur (Ghent University), Generation of hypohamiltonian graphs 16:20 - 16:45 Gary MacGillivray (University of Victoria), Hamiltonicity of Bell and Stirling colour graphs 16:50 - 17:15 Stanislaw Radziszowski (Rochester Institute of Technology), Chromatic vertex Folkman numbers, general Folkman problems, and related computational challenges Discrete Mathematical Biology, Part I Org: Torin Greenwood and Christine Heitsch (Georgia Institute of Technology) This pair of minisymposia will examine discrete models and combinatorial methods across a spectrum of mathematical biology. Problems in biology motivate new combinatorial methods, which have intrinsic mathematical appeal. Complementing this, new mathematical techniques bring advancements to biology. These talks exhibit the fruitful interplay between the fields. Tuesday June 13 10:20 - 10:45 Sharlee Climer (University of Missouri - St. Louis), Embracing the complexity of combinatorial GWAS 10:50 - 11:15 Joanna Ellis-Monaghan (Saint Michael's College), Ins and Outs of DNA Self-Assembly 11:20 - 11:45 Torin Greenwood (Georgia Institute of Technology), Using Experimental Data to Deconvolve Structural Signals 11:50 - 12:15 Ezra Miller (Duke University), Fruit fly wing veins as embedded planar graphs 12:20 - 12:45 Sonja Petrovic (Illinois Institute of Technology), Discrete methods for statistical network analysis in biology Discrete Mathematical Biology, Part II Org: Torin Greenwood and Christine Heitsch (Georgia Institute of Technology) This pair of minisymposia will examine discrete models and combinatorial methods across a spectrum of mathematical biology. Problems in biology motivate new combinatorial methods, which have intrinsic mathematical appeal. Complementing this, new mathematical techniques bring advancements to biology. These talks exhibit the fruitful interplay between the fields. Tuesday June 13 15:20 - 15:45 Peter Clote (Boston College), Network properties of RNA secondary structures 15:50 - 16:15 Elena Dimitrova (Clemson University), Unique Reduced Gr\"obner Bases of Ideals of Points 16:20 - 16:45 Tara Petrie (Simon Fraser University), Folding something other than laundry 16:50 - 17:15 Christian Reidys (Virginia Institute of Technology), a new grammar for PK-structures 17:20 - 17:45 David Sivakoff (Ohio State University), Discrete Excitable Media Entropy compression and the Lovasz Local Lemma Org: Michael Molloy (University of Toronto) The Lovasz Local Lemma is a powerful proof technique which proves the existence of an object, by showing that a random procedure attempting to produce it will succeed with positive probability. For example, every graph with certain properties has a colouring of a certain type. $\\$ In 2008, Moser introduced entropy compression, a technique to provide efficient algorithms which construct objects that the Local Lemma guarantees to exist. His technique has since been used to obtain new existence proofs using procedures where it is hard to apply traditional versions of the Local Lemma. For example, one can try to colour a graph by colouring vertices one-at-a-time, each time choosing a random colour that does not appear on the neighbourhood of the vertex. The spread of dependencies in such a procedure is usually too much for the Local Lemma. But procedures of this type can fit quite well into Moser's framework. Wednesday June 14 10:20 - 10:45 Fotis Iliopoulos (UC Berkeley), Stochastic Local Search and the Lovasz Local Lemma 10:50 - 11:15 Gwenael Joret (UniversitÃ© Libre de Bruxelles), Improved bound for AVD edge coloring 11:20 - 11:45 Piotr Micek (Jagiellonian University), Nonrepetitive colorings and entropy compression method 11:50 - 12:15 Michael Molloy (University of Toronto), Colouring graphs with small clique number Geometry and Combinatorial Optimization Org: Guyslain Naves (Aix-Marseille University) This session's focus is on geometric aspects of combinatorial optimization. Tuesday June 13 15:20 - 15:45 Marcel Celaya (Georgia Tech), The linear span of lattice points in the half-open unit cube 15:50 - 16:15 Robert Davis (Michigan State University), Detecting the Integer Decomposition Property in Reflexive Simplices 16:20 - 16:45 Guyslain Naves (Marseille University), Packing and covering with balls on Busemann surfaces 16:50 - 17:15 Andras Sebo (Grenoble), Tours, Colouring or Somewhere In Between 17:20 - 17:45 Nicholas Early (Penn State), How to Scale A Hypersimplex Graph Colouring, Part I Org: Luke Postle (University of Waterloo) Graph coloring is one the oldest and most storied areas of graph theory. Despite dating back to the days of the Four Color Conjecture, there has been much recent interest and active progress in this area, especially in the last few decades. Many generalizations of graph coloring, developed to tackle practical problems, can be extended beyond their original applications in order to attack new areas. This two-part minisymposium seeks to highlight a number of these interesting new developments by bringing together researchers in this classical field. Monday June 12 15:20 - 15:45 Michelle Delcourt (University of Illinois at Urbana-Champaign), On the List Coloring Version of Reed's Conjecture 15:50 - 16:15 Thomas Kelly (University of Waterloo), Beyond Degree-Choosability Toward a Local Epsilon Version of Reed's $\omega, \Delta, \chi$ conjecture 16:20 - 16:45 Sophie Spirkl (Princeton University), Even Pairs and Prism Corners in Perfect Graphs 16:50 - 17:15 David Wood (Monash University), Defective colouring of graphs excluding a subgraph or minor 17:20 - 17:45 Hehui Wu (Shanghai Center for Mathematical Sciences), Digraphs coloring and tournaments with large domination number Graph Colouring, Part II Org: Michelle Delcourt (University of Illinois at Urbana-Champaign) Graph coloring is one the oldest and most storied areas of graph theory. Despite dating back to the days of the Four Color Conjecture, there has been much recent interest and active progress in this area, especially in the last few decades. Many generalizations of graph coloring, developed to tackle practical problems, can be extended beyond their original applications in order to attack new areas. This two-part minisymposium seeks to highlight a number of these interesting new developments by bringing together researchers in this classical field. Tuesday June 13 10:20 - 10:45 Anton Bernshteyn (University of Illinois at Urbana-Champaign), Dirac's theorem for DP-critical graphs 10:50 - 11:15 Vida Dujmovic (University of Ottawa), Layered tree-compositions and graph colouring 11:20 - 11:45 Felix Joos (University of Birmingham), The Tree Packing Conjecture 11:50 - 12:15 Luke Postle (University of Waterloo), List Coloring with Requests 12:20 - 12:45 Yelena Yuditsky (McGill University), Gy\'arf\'as-Sumner Conjecture Is Almost Always True Graph Polynomials Org: Jason Brown (Dalhousie University) For a variety of combinatorial problems, such as network reliability and graph colourings, the models turn out to be graph polynomials. On the other hand, the investigation of various subgraph properties (such as independence and domination) leads one to explore the associated combinatorial sequences by formulating generating polynomials. In all cases, polynomials carry useful or even essential information about the underlying combinatorics, and the connections allow one to draw on classical areas of mathematics, such as analysis and algebra, in the investigations. Tuesday June 13 15:20 - 15:45 Jason Brown (Dalhousie University), Recent Results on Chromatic Polynomials 15:50 - 16:15 Ben Cameron (Dalhousie University), On the Unimodality of Independence Polynomials of Very Well-Covered Graphs 16:20 - 16:45 Danielle Cox (Mount Saint Vincent University), Analytic Properties of the Reliability Polynomial 16:50 - 17:15 Lucas Mol (University of Winnipeg), Roots of all-terminal reliability and node reliability polynomials 17:20 - 17:45 David Wagner (University of Waterloo), The algebra of flows in graphs Graph Structure and Algorithms I Org: Kathie Cameron and Shenwei Huang (Wilfrid Laurier University / University of New South Wales) 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 mini-symposium, we will hear a variety of exciting developments on classical and parameterized complexity of graph problems such as coloring, homomorphisms and graph search, and on structure of important classes of graphs and digraphs. Wednesday June 14 10:20 - 10:45 CÃ©sar HernÃ¡ndez Cruz (Universidad Nacional AutÃ³noma de MÃ©xico), Cograph minimal $(s,k)$-polar obstructions. 10:50 - 11:15 Edward Lee (University of New South Wales), Fast exponential-time algorithms via multivariate subroutines 11:20 - 11:45 Jing Huang (University of Victoria), End-vertices of lexicographic breadth first searches 11:50 - 12:15 Shenwei Huang (University of New South Wales), Linearly $\chi$-Bounding $(P_6,C_4)$-Free Graphs 12:20 - 12:45 Arash Rafiey (Indiana State University), Bi-arc Digraphs and Conservative Polymorphisms Graph Structure and Algorithms II Org: Kathie Cameron and Shenwei Huang (Wilfrid Laurier University / University of New South Wales) 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 mini-symposium, we will hear a variety of exciting developments on classical and parameterized complexity of graph problems such as coloring, homomorphisms and graph search, and on structure of important classes of graphs and digraphs. Wednesday June 14 15:20 - 15:45 Kathie Cameron (Wilfrid Laurier University), Solving the clique cover problem on (bull, $C_4$)-free graphs 15:50 - 16:15 Elaine Eschen (West Virginia University), Colored graph completion problem for classes of chordal graphs 16:20 - 16:45 Pavol Hell (Simon Fraser University), Digraph Analogues of Nice Graph Classes 16:50 - 17:15 Chinh Hoang (Wilfrid Laurier University), Coloring graphs without small forbidden subgraphs 17:20 - 17:45 R. Sritharan (University of Dayton), Graph modification problem Graphs and Games: the Mathematics of Richard Nowakowski (Part I) Org: Shannon Fitzpatrick (University of Prince Edward Island) This minisymposium is in honour of Richard Nowakowski, on the occasion of his 65th birthday. Throughout his career, Richard has worked on a variety of problems, but his influence has been most keenly felt in the fields of Graph Searching and Combinatorial Game Theory. This is an opportunity for Richard's former students, collaborators, and colleagues to present research in areas of particular interest to Richard, and celebrate his contribution to mathematics in Canada. Tuesday June 13 10:20 - 10:45 Nancy Clarke (Acadia University), Cops and Robbers with Gangs 10:50 - 11:15 Stephen Finbow (Saint Francis Xavier University), Eternal Domination Game on King Graphs 11:20 - 11:45 Shannon Fitzpatrick (University of Prince Edward Island), The Game of k-Visibility Cops and Robber 11:50 - 12:15 Neil McKay (University of New Brunswick, Saint John), Brussels Sprouts, Lattices, and Game Trees 12:20 - 12:45 Margaret-Ellen Messinger (Mount Allison University), Chip Diffusion Graphs and Games: the Mathematics of Richard Nowakowski (Part II) Org: Margaret-Ellen Messinger (Mount Allison University) This minisymposium is in honour of Richard Nowakowski, on the occasion of his 65th birthday. Throughout his career, Richard has worked on a variety of problems, but his influence has been most keenly felt in the fields of Graph Searching and Combinatorial Game Theory. This is an opportunity for Richard's former students, collaborators, and colleagues to present research in areas of particular interest to Richard, and celebrate his contribution to mathematics in Canada. Wednesday June 14 10:20 - 10:45 Anthony Bonato (Ryerson University), Games and graphs: the legacy of RJN 10:50 - 11:15 Jason Brown (Dalhousie University), My Streak of Independence with Richard 11:20 - 11:45 Chris Duffy (Dalhousie University), Shapleyâ€“Shubik Power Index as a Model for Spread of Influence in a Network 11:50 - 12:15 Gena Hahn (UniversitÃ© de MontrÃ©al), Loops or no loops? 12:20 - 12:45 Pawel Pralat (Ryerson University), A probabilistic version of the game of Zombies and Survivors on graphs Graphs and Games: the Mathematics of Richard Nowakowski (Part III) Org: Nancy Clarke (Acadia University) This minisymposium is in honour of Richard Nowakowski, on the occasion of his 65th birthday. Throughout his career, Richard has worked on a variety of problems, but his influence has been most keenly felt in the fields of Graph Searching and Combinatorial Game Theory. This is an opportunity for Richard's former students, collaborators, and colleagues to present research in areas of particular interest to Richard, and celebrate his contribution to mathematics in Canada. Wednesday June 14 15:20 - 15:45 Art Finbow (Saint Mary's University), Extendable Vertices in Well-Covered Graphs 15:50 - 16:15 Bert Hartnell (Saint Mary's University), Parity Dissociation Graphs 16:20 - 16:45 Jeannette Janssen (Dalhousie University), An application of Hall's theorem to linear embeddings of graphs 16:50 - 17:15 Mike Plummer (Vanderbilt University), 4-regular planar well-covered graphs In honour of the work of Alex Rosa (Part I) Org: Peter Danziger, Tommaso Traetta (Ryerson University) On the occasion of Alex Rosa's 80th birthday we offer these two sessions in honour of his work. Particularly known for his work on Triple Sytems, Dr. Rosa has published in many areas of Combinatorics including Graph Labellings, Steiner Triple systems and Graph Decompositions. He has over 200 refereed journal publications, many books, and was a founding editor of the Journal of Combinatorial Designs. He has been awarded the prestigous Euler medal by the Institute of Combinatorics and its Applications. He is universally recognised as one of the leading lights of modern Combinatorics, his activities and influence in Discrete Mathematics continue to this day. These sessions will highlight recent progress in areas of interest in Design Theory and beyond to which Alex has blazed the trail. Tuesday June 13 10:20 - 10:45 Peter Dukes (University of Victoria), Fractional decompositions and completing partial latin squares 10:50 - 11:15 FranÄ›k FrantiÅ¡ek (McMaster University), d-step approach to periodical structures in strings 11:20 - 11:45 Esther Lamken (University of Caltech), An existence theory for incomplete designs 11:50 - 12:15 Nabil Shalaby (Memorial University), Rosa sequences 12:20 - 12:45 Doug Stinson (University of Waterloo), Some results on the existence of t-all-or-nothing transforms over arbitrary alphabets In honour of the work of Alex Rosa (Part II) Org: Peter Danziger, Tommaso Traetta (Ryerson University) On the occasion of Alex Rosa's 80th birthday we offer these two sessions in honour of his work. Particularly known for his work on Triple Systems, Dr. Rosa has published in many areas of Combinatorics including Graph Labellings, Steiner Triple systems and Graph Decompositions. He has over 200 refereed journal publications, many books, and was a founding editor of the Journal of Combinatorial Designs. He has been awarded the prestigious Euler medal by the Institute of Combinatorics and its Applications. He is universally recognised as one of the leading lights of modern Combinatorics, his activities and influence in Discrete Mathematics continue to this day. These sessions will highlight recent progress in areas of interest in Design Theory and beyond to which Alex has blazed the trail. Tuesday June 13 15:20 - 15:45 Andrea Burgess (University of New Brunswick), Recent advances on the Hamilton-Waterloo problem 15:50 - 16:15 Barbara Maenhaut (University of Queensland), Hamilton Decompositions of Line Graphs 16:20 - 16:45 David Pike (Memorial University), Colourings of Group Divisible Designs 16:50 - 17:15 Brett Stevens (Carleton University), Kirkman-Hamilton triple systems 17:20 - 17:45 Tommaso Traetta (Ryerson University), Reverse $2$-factorizations via graceful labelings Pursuit-Evasion Games on Graphs Org: Bill Kinnersley (University of Rhode Island) Pursuit-evasion games are a type of combinatorial game in which one or more pursuers'' attempts to capture a mobile evader'' within some environment (often represented by a graph). In addition to being of theoretical interest, pursuit-evasion games have applications in a variety of areas, from mobile computing to military operations. This minisymposium will focus on recent developments in the field, with a particular emphasis on the classic game of Cops and Robbers. Monday June 12 15:20 - 15:45 Danny Dyer (Memorial University), Watching Halin graphs 15:50 - 16:15 Saeed Aliasghar Hosseini (Simon Fraser University), Cops and Robbers on Oriented Grids 16:20 - 16:45 Bill Kinnersley (University of Rhode Island), Bounds on the Capture Time of Graphs 16:50 - 17:15 Natasha Komarov (St. Lawrence University), Using spotlights to find a robber 17:20 - 17:45 Kerry Ojakian (Bronx Community College (C.U.N.Y.)), Extremal Cop-Win Graphs Reconfiguration Org: Ruth Haas (U. Hawaii, Manoa) The reconfiguration version of a problem concerns when one feasible solution to a problem can be reconfigured to another via an allowable set of operations. There has recently been a lot of interest in this topic including reconfiguration of graph coloring and domination among other problems These talks give an overview of the area as well as current work and open problems. Wednesday June 14 15:20 - 15:45 Naomi Nishimura (Waterloo), Introduction to Reconfiguration 15:50 - 16:15 Benjamin Moore (Simon Fraser University), Some observations on circular colouring mixing for $(p,q)$-colourings when $p/q <4$ 16:20 - 16:45 Karen Seyffarth (U Calgary), Reconfiguring Vertex Colourings of 2-trees 16:50 - 17:15 Moritz MÃ¼hlenthaler (Erlangen-Nurnberg), Reconfiguration of Common Independent Sets of Partition Matroids 17:20 - 17:45 Beth Novick (Clemson University), Structural Properties of Shortest Path Graphs Topological and Geometric Algorithms, Part I Org: Mark Ellingham and Joanna Ellis-Monaghan (Vanderbilt University and Saint Michael's College) One of the strengths of discrete mathematics is its broad applicability in a wide range of other fields. For example, many problems in discrete mathematics have a topological or geometric component or setting. Moreover, particularly for questions driven by applications, many such problems include algorithmic approaches. This minisymposium brings together researchers whose work in discrete mathematics involves both spatial and computational considerations, many with a sub-theme of structural questions arising from biological and other applications. Examples include: graph drawing in various settings; determining folding configurations for paper, DNA, or protein structures; and generating graph embeddings with certain symmetries. Monday June 12 10:20 - 10:45 Ileana Streinu (Smith College), Rigidity and flexibility in molecular graphs: the KINARI experience 10:50 - 11:15 Ciprian Borcea (Rider University), Periodic frameworks: graphs, placements, deformations 11:20 - 11:45 Christine Heitsch (Georgia Institute of Technology), Meanders and RNA Folding 11:50 - 12:15 NataÅ¡a Jonoska (University of South Florida), Topological graph theory in DNA self-assembly and DNA recombination 12:20 - 12:45 Ada Morse (University of Vermont), DNA Origami and Knots in Graphs Topological and Geometric Algorithms, Part II Org: Mark Ellingham and Joanna Ellis-Monaghan (Vanderbilt University and Saint Michael's College) One of the strengths of discrete mathematics is its broad applicability in a wide range of other fields. For example, many problems in discrete mathematics have a topological or geometric component or setting. Moreover, particularly for questions driven by applications, many such problems include algorithmic approaches. This minisymposium brings together researchers whose work in discrete mathematics involves both spatial and computational considerations, many with a sub-theme of structural questions arising from biological and other applications. Examples include: graph drawing in various settings; determining folding configurations for paper, DNA, or protein structures; and generating graph embeddings with certain symmetries. Thursday June 15 10:20 - 10:45 Mark Ellingham (Vanderbilt University), Graph embeddings and DNA reporter strands 10:50 - 11:15 Ellen Gethner (University of Colorado Denver), Thickness, Simultaneous Embeddings, and Graph Sculpting 11:20 - 11:45 Anna Lubiw (University of Waterloo), Flipping Edge-Labelled Triangulations 11:50 - 12:15 Therese Biedl (University of Waterloo), Optimum-width upward drawings of trees 12:20 - 12:45 Sue Whitesides (University of Victoria), Visibility Graphs: a survey