Sara Billey's Public Talks and Lectures

Here you can find some links, slides and lecture notes from seminars, colloquia, and talks given recently.

• Combinatorial Characterizations of Smooth Positroid Varieties via Pattern Avoidance, Spirographs, and Johnson Graphs . Cascade Lectures in Combinatorics April 22, 2023. Joint with Jordan Weaver and Christian Krattenthaler.

• Existence and hardness of conveyor belts . Michigan State University, April 14, 2021. Joint with Baird, Demaine, Demaine, Eppstein, Fekete, Gordon, Griffin, Mitchell, Swanson. Handout.

• Part I: Basic Schubert Calculus (Hilbert's 15th Problem) and Part II: Basic Schubert Calculus (Pipe Dreams) . ICERM: Introductory Workshop: Combinatorial Algebraic Geometry February 1, 2021. Video I . Video II .

• Limit Laws for q-Hook Formulas . University of Kentucky Discrete CATS Seminar November 2, 2020, Joint with Josh Swanson. Video .

• Boolean product polynomials, Schur positivity, and Chern plethysm . New Directions in Algebraic Combinatorics: Adriano Garsia's 90th Birthday Conference. June 19, 2019.

• Handout: Tactile Patterns in Art and Math . Lecture by Sara Billey and Timea Tihanyi. Mathday 2019.

• Cylotomic Generating Functions . Banff International Research Station, March 2019.

• Patterns in Standard Young Tableaux . Sergey Fomin 60th Birthday Conference, November 9, 2018.

• "What is Combinatorics?" for Frontiers in Math Webniar for National Academies of Science, Engineering, and Medicine, October 2018.

• On the Distribution of Major Index on Sta\ ndard Young Tableaux and Fake Degrees of Coinvariant Algebras. ICM Satillite Conference in Miami, July 28, 2018.

• Boolean Product Polynomials and the Resonance Arrangement. FPSAC, July 17, 2018.

• Patterns in Standard Young Tableaux. Permutation Patterns, July 10, 2018.

• Reduced words and a formula of Macdonald given at University of Kansas at the "Graduate Student Combinatorics Conference, 2017" April 8, 2017.

• Bitcoin, Blockchain and the Boogeyman behind it. UW Mathday,March 19, 2018.

• Enumeration of Parabolic Double Cosets for Coxeter Groups given at Herstmonceaux Castle in England at "Algebraic Combinatorics and Group Actions Conference" June 12, 2016.

• LSU Student Colloquium Lectures: Trees, Tanglegrams, and Tangled Chains and Enumeration of Parabolic Double Cosets, Leap Day February 29, 2016.

• Trees, Tanglegrams, and Tangled Chains Discrete Math Conference at Worcester Poly Tech on September 12, 2015. See also the video version from BIRS Workshop on "Positivity in Algebraic Combinatorics" August 15-16, 2015.

• Computer Proofs: Coming Soon to a Theorem Near You Mathday, 2015. A video version comes in two parts: Part I and Part II .

• Quasisymmetric Functions June 9-13, 2014. Three lecture series at ECCO at Universidad de Los Andes, Bogota Colombia. Also here.

• Math inspired by origami Mathday March 24, 2014. Based on work by Butler,Demaine, Graham, and Tachi.

• Coxeter-Knuth Graphs and a Signed Little Bijection AMS-MAA Joint Meetings January 17, 2014. Joint with Zach Hamaker, Austin Roberts and Ben Young. Extended version given at Stanford and Berkeley in February: HERE.

• Patterns in Permutations and Diagrams ICERM Febrary 11, 2013, Sage Demo

• Consequences of the Lakshmibai-Sandhya Theorem Four lectures plus supporting materials written for MSJ-SI 2012 Schubert calculus held in Osaka, Japan. July 2012.

• Recent advances in symmetric functions and tableaux combinatorics Current Problems Seminar, UW. March 1, 2012.

• An Introduction to the Combinatorics and Geometry of Schubert Varieties Nebraska Conference for Undergraduate Women in Mathematics, January 28, 2012.

• Consequences of the Lakshmibai-Sandhya Theorem AWM 40th Anniversary Conference --Sept 18, 2011.

• Mathematics of the Web written for Mathday -- March 21, 2011.

• Rank Varieties written for CMS Special Session in Vancouver, December 2010.

• A Stratification of the Space of Branched Polymers written for Combinatorics 2010: Advances, Trends and Speculations -- March 26, 2010.

• An Introduction to Affine Grassmannians written for MSRI -- Connections Workshop, January 2009.

• Affine Colored Partitions and Affine Grassmannians written for AMS Special Session, January 2008.

• A computational approach to Schubert varieties written for Sage Days 2007. Also includes open problems on computer verification techniques and SAGE Dreams.

• Grassmannians and Other Schubert Varieties IMA Workshop on "What is Algebraic Geometry?"

• Intersecting Schubert Varieties Chennai Mathematical Institute (similar to talks given in Berkeley and UBC during the spring of 2005)

• FPSAC 2005 Taormina, Italy

• Schubert Varieties under a Microscope given at the AMS Summer Institute in Algebraic Geometry in Seattle.