Approximation Algorithms (IM3) 
Org: Chaitanya Swamy (University of Waterloo) 

Tuesday May 25 
15:30  15:55  Deeparnab Chakrabarty (Dartmouth College), Algorithms for minimum norm combinatorial optimization 
16:00  16:25  Chandra Chekuri (University of Illinois, UrbanaChampaign), Covering Multiple Submodular Constraints and Applications 
16:30  16:55  Anupam Gupta (Carnegie Mellon University), MatroidBased TSP Rounding for HalfIntegral Solutions 
17:00  17:25  Aleksandar Nikolov (University of Toronto), Maximizing Determinants under Combinatorial Constraints 
17:30  17:55  Ola Svensson (Ecole Polytechnique Fédérale de Lausanne), The PrimalDual method for Learning Augmented Algorithms 

Combinatorial Optimization  Part I (IM1) 
Org: László Végh (London School of Economics) 

Tuesday May 25 
11:20  11:45  Christoph Hunkenschröder (TU Berlin), BlockStructured Integer and Linear Programming in Near Linear Time 
11:50  12:15  Edin Husić (London School of Economics), Approximating Nash Social Welfare under Rado Valuations 
12:20  12:45  Jason Li (Carnegie Mellon University), Deterministic Mincut in AlmostLinear Time 
12:50  13:15  Kent Quanrud (Purdue University), Faster Algorithms for Rooted Connectivity in Directed Graphs 
13:20  13:45  Sahil Singla (Princeton University and Institute for Advanced Study), Improved Truthful Mechanisms for Combinatorial Auctions 

Combinatorial Optimization  Part II (IM8) 
Org: László Végh (London School of Economics) 

Wednesday May 26 
15:30  15:55  Vera Traub (ETH Zurich), Improving the Approximation Ratio for Capacitated Vehicle Routing 
16:00  16:25  Zhuan Khye Koh (London School of Economics), An Accelerated NewtonDinkelbach Method and its Application to Two Variables Per Inequality Systems 
16:30  16:55  Sharat Ibrahimpur (University of Waterloo), Approximation Algorithms for Stochastic Minimum Norm Combinatorial Optimization 
17:00  17:25  Nathan Klein (University of Washington), Approximating the minimum $k$edge connected multisubgraph problem 
17:30  17:55  Sami Davies (University of Washington), Scheduling with Communication Delays via LP Hierarchies and Clustering 

Combinatorics on Posets  Part I (IM13) 
Org: Tom Trotter (Georgia Institute of Technology) 

Thursday May 27 
15:30  15:55  Patrice Ossona de Mendez (CNRS, École des Hautes Études en Sciences Sociales), Small, sparse and ordered 
16:00  16:25  Gwenaël Joret (Université Libre de Bruxelles), The extension dimension and the linear extension polytope of a poset 
16:30  16:55  Bartłomiej Bosek (Jagellonian University), Dilworth's Theorem for Borel Posets 
17:00  17:25  Jarosław Grytczuk (Technical University of Warsaw), Variations on twins in permutations 
17:30  17:55  Piotr Micek (Jagellonian University), Excluding a ladder 

Combinatorics on Posets  Part II (IM16) 
Org: Tom Trotter (Georgia Institute of Technology) 

Friday May 28 
11:20  11:45  Torsten Ueckerdt (Karlsruhe Institute of Technology), The queue number of posets 
11:50  12:15  Łukasz Bożyk (University of Warsaw), Vertex deletion into bipartite permutation graphs 
12:20  12:45  Michał Seweryn (Jagellonian University), Dimension of posets with kouterplanar cover graphs. 
12:50  13:15  Marcin Witkowski (Adam Mickiewicz University), Adjacency posets of outerplanar graphs 

Discrete and algorithmic mathematics in biology and epidemiology  Part I (IM9) 
Org: Pengyu Liu (Simon Fraser University) 

Wednesday May 26 
15:30  15:55  Baptiste Elie (MIVGEC, Université Montpellier), The source of individual heterogeneity shapes infectious disease outbreaks 
16:00  16:25  Xingru Chen (Dartmouth College), Effectiveness of Massive Travel Restrictions on Mitigating Outbreaks of COVID19 in China 
16:30  16:55  Wasiur KhudaBukhsh (Ohio State University), Chemical reaction networks with covariates 
17:00  17:25  Joel Miller (La Trobe University), Simulating epidemic spread on contact networks 

Discrete and algorithmic mathematics in biology and epidemiology  Part II (IM11) 
Org: Pengyu Liu (Simon Fraser University) 

Thursday May 27 
11:20  11:45  Jianrong Yang (Sun Yatsen University), Developmental cell lineage trees, and the quantitative comparisons between them 
11:50  12:15  Christoph Weitkamp (Universität Göttingen), GROMOVWASSERSTEIN BASED PHYLOGENETIC TREE SHAPE COMPARISON 
12:20  12:45  Louxin Zhang (National University of Singapore), The Bourque Distances for Mutation Trees of Cancers 
12:50  13:15  Julia Palacios (Stanford University), Distancebased summaries and modeling of evolutionary trees 

Discrete Geometry (IM4) 
Org: Yufei Zhao (MIT) 

Wednesday May 26 
11:20  11:45  Dor Minzer (Massachusetts Institute of Technology), Optimal tiling of the Euclidean space using permutationsymmetric bodies 
11:50  12:15  Alexandr Polyanskii (Moscow Institute of Physics and Technology), A cap covering theorem 
12:20  12:45  Yair Shenfeld (Massachusetts Institute of Technology), Extremal structures of logconcave sequences via convex geometry 
12:50  13:15  Cosmin Pohoata (Yale University), On the Zarankiewicz problem for graphs with bounded VCdimension 
13:20  13:45  Josh Zahl (University of British Columbia), Sphere tangencies, line incidences, and Lie's linesphere correspondence 

Extremal Combinatorics (IM5) 
Org: Natasha Morrison (University of Victoria) 

Wednesday May 26 
11:20  11:45  Wojciech Samotij (Tel Aviv University), Sharp thresholds for Ramsey properties 
11:50  12:15  Shoham Letzter (University College London), Chiboundedness of graphs with no cycle with exactly k chords 
12:20  12:45  Katherine Staden (University of Oxford), Ringel's tree packing conjecture 
12:50  13:15  Rob Morris (Instituto de Matemática Pura e Aplicada), Flat Littlewood Polynomials Exist 
13:20  13:45  Marcelo Campos (Instituto de Matemática Pura e Aplicada), Singularity of random symmetric matrices revisited 

Generating series and confined lattice walks  Part I (IM12) 
Org: Thomas Dreyfus (CNRS, Université de Strasbourg) and Andrew Elvey Price (CNRS, Université de Tours) 

Thursday May 27 
11:20  11:45  Lucia Di Vizio (CNRS, Université de VersaillesSt Quentin), Differential transcendence for the Bell numbers and their relatives 
11:50  12:15  Helen Jenne (Université de Tours and Université d'Orléans), Threedimensional lattice walks confined to an octant: nonrationality of the second critical exponent 
12:20  12:45  Michael Singer (North Carolina State University), Differentially Algebraic Generating Series for Walks in the Quarter Plane 
12:50  13:15  Michael Wallner (TU Wien), More Models of Walks Avoiding a Quadrant 

Generating series and confined lattice walks  Part II (IM17) 
Org: Thomas Dreyfus (CNRS, Université de Strasbourg) and Andrew Elvey Price (CNRS, Université de Tours) 

Friday May 28 
11:20  11:45  Irène Markovici (Université de Lorraine), Bijections between walks inside a triangular domain and Motzkin paths of bounded amplitude 
11:50  12:15  Alin Bostan (INRIA Saclay ÎledeFrance), On the Dtranscendence of generating functions for singular walks in the quarter plane 
12:20  12:45  Manuel Kauers (Johannes Kepler Universität), Quadrant Walks Starting Outside the Quadrant 
12:50  13:15  Marni Mishna (Simon Fraser University), Lattice Walk Classification: algebraic, analytic, and geometric perspectives 

In honour of Pavol Hell  Part I (IM6) 
Org: Gary MacGillivray (University of Victoria) 

Wednesday May 26 
11:20  11:45  Xuding Zhu (Zhejiang Normal University), On Hedetniemi's Conjecture 
11:50  12:15  Shenwei Huang (Nankai University), kcritical graphs in P5free graphs 
12:20  12:45  Jaroslav Nešetřil (Charles University), In praise of homomorphisms 
12:50  13:15  Kathie Cameron (Wilfred Laurier University), A Parity Theorem About Trees with Specified Degrees 
13:20  13:45  Arash Rafiey (Indiana State University), 2SAT and Transitivity Clauses 

In honour of Pavol Hell  Part II (IM10) 
Org: Gena Hahn (Université de Montréal) and Gary MacGillivray (University of Victoria) 

Wednesday May 26 
15:30  15:55  Richard Brewster (Thompson Rivers University), Characterizing Circular Colouring Mixing for $p/q < 4$ 
16:00  16:25  David Kirkpatrick (UBC), Forbidden Induced Subgraphs for $k$Nested Interval Graphs 
16:30  16:55  Jing Huang (University of Victoria), Obstructions for local tournament orientation completions 
17:00  17:25  Cesar HernandezCruz (Universidad Nacional Autónoma de México), Strongly Chordal Digraphs 
17:30  17:55  Gary MacGillivray (University of Victoria), Frugal homomorphisms 

Invitation to distributed graph algorithms (IM2) 
Org: Jara Uitto (Aalto University) 

Tuesday May 25 
11:20  11:45  Yannic Maus (Technion, Israel Institute of Technology), Distributed Graph Coloring Made Easy 
11:50  12:15  Sebastian Brandt (ETH Zurich), Round Elimination: A Technique for Proving Distributed Lower Bounds 
12:20  12:45  Seri Khoury (Simons Institute, UC Berkeley), The congest model: a glimpse into the challenges that arise due to bandwidth limitations. 
12:50  13:15  Soheil Behnezhad (University of Maryland), Locality and the Stochastic Matching Problem 
13:20  13:45  Huang Lingxiao (Institute for Interdisciplinary Information Sciences), Coreset construction for clustering: offline and distributed settings 

Invitation to Reconfiguration  Part I (IM14) 
Org: Nicolas Bousquet (CNRS, Université de Lyon) and Anna Lubiw (University of Waterloo) 
“Reconfiguration” is about changing one configuration to another via discrete steps, for example sorting a list by swapping pairs of adjacent elements, or changing one proper colouring of a graph to another by recolouring one vertex at a time. We may ask: Is there a reconfiguration path between any two configurations? How short a path? How efficiently can it be found? How many reconfiguration steps to a random configuration?
These questions arise in various fields such as discrete geometry (flip
distance), combinatorics (graph recoloring, token swapping), bioinformatics (phylogenetics), combinatorial game theory (puzzles), random sampling (Monte Carlo Markov chains), and combinatorial optimization (Hirsch’s conjecture).
The talks in this minisymposium give a sample of recent results in these
areas. 

Thursday May 27 
15:30  15:55  Erik Demaine & Nicole Wein (MIT & University of Waterloo), Hardness of Token Swapping on Trees 
16:00  16:25  Colin R Defant & Noah Kravitz (Princeton University), Random Friends and Strangers Walking on Random Graphs 
16:30  16:55  Emo Welzl (ETH Zurich), VertexConnectivity of Triangulation Flip Graphs of Planar Point Sets 
17:00  17:25  Jean Cardinal (Université Libre de Bruxelles), Flip Distances between Graph Orientations 
17:30  17:55  Linda Kleist (Technische Universität Braunschweig), Flip graphs and Rainbow cycles 

Invitation to Reconfiguration  Part II (IM18) 
Org: Nicolas Bousquet (CNRS, Université de Lyon) and Anna Lubiw (University of Waterloo) 
“Reconfiguration” is about changing one configuration to another via discrete steps, for example sorting a list by swapping pairs of adjacent elements, or changing one proper colouring of a graph to another by recolouring one vertex at a time. We may ask: Is there a reconfiguration path between any two configurations? How short a path? How efficiently can it be found? How many reconfiguration steps to a random configuration?
These questions arise in various fields such as discrete geometry (flip distance), combinatorics (graph recoloring, token swapping), bioinformatics (phylogenetics), combinatorial game theory (puzzles), random sampling (Monte Carlo Markov chains), and combinatorial optimization (Hirsch’s conjecture).
The talks in this minisymposium give a sample of recent results in these
areas. 

Friday May 28 
15:30  15:55  Satyan Devadoss (University of San Diego), Associativity reconfigurations: Colors, Graphs, Polytopes 
16:00  16:25  Jonathan Narboni (Université de Bordeaux), On Vizing's edge colouring question 
16:30  16:55  Daniel Cranston (Virginia Commonwealth University), In Most 6regular Toroidal Graphs All 5colorings are Kempe Equivalent 
17:00  17:25  Marc Heinrich (University of Leeds), Glauber dynamics for colourings of chordal graphs and graphs of bounded treewidth 
17:30  17:55  Kuikui Liu (University of Washington), Markov Chain Analysis Through the Lens of HighDimensional Expanders 

Invitation to Sparsity (IM7) 
Org: Zdeněk Dvořák (Charles University) 

Wednesday May 26 
11:20  11:45  Zdeněk Dvořák (Charles University), Sparsity: Concepts and applications 
11:50  12:15  Felix Reidl (Birkbeck University of London), Algorithmic aspects I 
12:20  12:45  Michał Pilipczuk (University of Warsaw), Algorithmic aspects II 
12:50  13:15  Patrice Ossona de Mendez (CNRS, École des Hautes Études en Sciences Sociales), A model theoretical approach to sparsity 
13:20  13:45  Sebastian Siebertz (University of Bremen), Characterizing sparsity by games. 

Probabilistic Approaches (IM15) 
Org: Jozef Skokan (London School of Economics) 

Thursday May 27 
15:30  15:55  Annika Heckel (LudwigMaximiliansUniversität München), How does the chromatic number of a random graph vary? 
16:00  16:25  Matthew Jenssen (University of Birmingham), Singularity of random symmetric matrices revisited 
16:30  16:55  Jinyoung Park (Institute for Advanced Study), On a problem of M. Talagrand 
17:00  17:25  Will Perkins (University of Illinois at Chicago), Correlation decay, phase transitions, and enumeration 
17:30  17:55  Mehtaab Sawhney (Massachusetts Institute of Technology), Friendly bisections of random graphs 

Structural Graph Theory (IM19) 
Org: Sergey Norin (McGill University) 

Friday May 28 
15:30  15:55  Rose McCarty (University of Waterloo), Connectivity for adjacency matrices and vertexminors 
16:00  16:25  Édouard Bonnet (CNRS, ÉNS Lyon), Twinwidth 
16:30  16:55  Richard Montgomery (University of Birmingham), A solution to Erdős and Hajnal's odd cycle problem 
17:00  17:25  Sophie Spirkl (University of Waterloo), Excluding a tree and a biclique 
17:30  17:55  ChunHung Liu (Texas A&M University), Asymptotic dimension of minorclosed families and beyond 