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, Urbana-Champaign), Covering Multiple Submodular Constraints and Applications 16:30 - 16:55 Anupam Gupta (Carnegie Mellon University), Matroid-Based TSP Rounding for Half-Integral 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 Primal-Dual 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), Block-Structured 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 Almost-Linear 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 Newton-Dinkelbach 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 multi-subgraph 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 k-outerplanar 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 COVID-19 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 Yat-sen University), Developmental cell lineage trees, and the quantitative comparisons between them 11:50 - 12:15 Christoph Weitkamp (Universität Göttingen), GROMOV-WASSERSTEIN 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), Distance-based 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 permutation-symmetric 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 log-concave sequences via convex geometry 12:50 - 13:15 Cosmin Pohoata (Yale University), On the Zarankiewicz problem for graphs with bounded VC-dimension 13:20 - 13:45 Josh Zahl (University of British Columbia), Sphere tangencies, line incidences, and Lie's line-sphere 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), Chi-boundedness 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 Versailles-St Quentin), Differential transcendence for the Bell numbers and their relatives 11:50 - 12:15 Helen Jenne (Université de Tours and Université d'Orléans), Three-dimensional lattice walks confined to an octant: non-rationality 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 Île-de-France), On the D-transcendence 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), k-critical graphs in P5-free 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), 2-SAT 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 Hernandez-Cruz (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), bio-informatics (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), Vertex-Connectivity 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), bio-informatics (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 6-regular Toroidal Graphs All 5-colorings 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 High-Dimensional 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 (Ludwig-Maximilians-Universität 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 vertex-minors 16:00 - 16:25 Édouard Bonnet (CNRS, ÉNS Lyon), Twin-width 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 Chun-Hung Liu (Texas A&M University), Asymptotic dimension of minor-closed families and beyond