DATE	SPEAKER	TITLE (click to show abstract)
January 30th	Max Wimberley, UC Berkeley	Introduction to the Schiffmann Algebra and its Applications Discovered by Schiffmann and Vasserot in 2008 as the Hall Algebra of an elliptic curve, the Schiffmann algebra has proven to be a remarkably useful tool in unifying and generalizing many topics in symmetric function theory, including the diagonal harmonics and the shuffle conjecture. My talk will focus on providing an accessible exposition of the algebra, its presentations and its symmetries, grounded in computation. As time allows, I will discuss my own investigation into a particular Poisson degeneration of the algebra and its relationship to a conjectured formula for the "triagonal harmonics," the version of the diagonal harmonics with three alphabets of variables instead of two. Recording (passcode: rZ*PYT7T)
February 6th	Tamsen McGinley, Santa Clara University	Crystals Graphs, Perforated Tableaux, and Combinatorial Objects Crystal graphs of biwords are directed graphs whose nodes are biwords and whose edges are determined by "crystal operators". These are used to model irreducible representations of GL_n . We present a new model for the nodes of a crystal graph, called a "perforated tableaux", on which the crystal operators are easily defined. We show that several well-known combinatorial objects, including semi-standard Young tableaux, Littlewood-Richardson fillings, and the Robinson-Schensted-Knuth correspondence, naturally appear in the setting of perforated tableaux. Recording (passcode: 31?.^Nrr)
Friday, February 10th, Evans 740, 4 PM	Sarah Brauner, University of Minnesota	Configuration spaces and combinatorial algebras In this talk, I will discuss connections between configuration spaces, an important class of topological space, and combinatorial algebras arising from the theory of reflection groups. In particular, I will present work relating the cohomology rings of some classical configuration spaces—such as the space of n ordered points in Euclidean space—with Solomon’s descent algebra and the peak algebra. The talk will be centered around two questions. First, how are these objects related? Second, how can studying one inform the other? This is joint, on-going work with Marcelo Aguiar and Vic Reiner. Recording (passcode: n%vT%h5$)
February 13th	No Seminar
February 20th	Academic Holiday - No Seminar
February 27th	Bernd Sturmfels, UC Berkeley	Algebraic Statistics, Scattering, and Geometric Combinatorics We discuss themes at the interface of algebraic statistics and particle physics that rely heavily on methods from geometric combinatorics. Our journey starts with maximum likelihood estimation for discrete models, it visits scattering amplitudes and moduli spaces, and it concludes with a recent article on likelihood degenerations. Our actors include matroids, hyperplane arrangements, very affine varieties, and tropical numerics. Recording (passcode: ZGx@^8dD)
March 6th	Gene B. Kim, Stanford	Golf and gambling Daily fantasy sports (DFS) is a multi-billion dollar industry. Despite the resemblance to sports betting, it has been declared as a game of skill in most US states; at its essence, DFS is a game of probabilistic optimization. We will discuss how to use data and Markov chains to model golf and use them to potentially multiply our investments by 10,000+ (and maybe even win a million dollars!)
Tuesday March 7th, Evans 748, 4 PM	Bruce Sagan, Michigan State University	Stirling numbers for complex reflection groups The ordinary Stirling numbers count set partitions and permutations of {1,2,...,n} by number of subsets and number of cycles, respectively. We show how to generalize these concepts to a complex reflection group. The ordinary Stirling numbers are recovered in type A. It turns out that often these Stirling numbers can be expressed in terms of elementary and homogeneous symmetric functions. We also make a connection with super coinvariant algebras. All terminology concerning Stirling numbers, symmetric functions, and complex reflection groups will be defined. This is joint work with Joshua Swanson.
March 13th	Ray Li, UC Berkeley
March 20th	Lucy Martinez, Rutgers University
March 27th	Spring Break - No Seminar
April 3rd	Joseph Pappe, UC Davis
April 10th	Yan Zhuang, Davidson College
April 17th	Dustin Ross, SFSU
April 24th	Mark Haiman, UC Berkeley
May 1st	Anastasia Chavez, St. Mary's College of CA
May 3rd, time and place TBA	Matt Hogancamp, Northeastern University

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