Wednesday May 3, 4:00pm-5:10pm
Padelford
C-401
Pre-Seminar 3:30pm-3:55pm in PDL C-401
ABSTRACT
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Richard Stanley introduced the chromatic symmetric function $X_G$ of a simple graph $G$, which is the sum of all possible proper colorings with colors $\{1,2,3,\ldots \}$ coded as monomials in commuting variables. These formal power series are symmetric functions and generalize the chromatic polynomial. Soojin Cho and Stephanie van Willigenburg found that, given a sequence of connected graphs $G_1,G_2, \ldots$ where $G_i$ has $i $ vertices, $\{X_{G_i}\}$ forms a basis for the algebra of symmetric functions. This provides a multitude of new bases since they also discovered that only the sequence of complete graphs provides a basis that is equivalent to a classical basis, namely the elementary symmetric functions. This talk will discuss new results on chromatic symmetric functions using these new and old bases, and additionally we will also resolve Stanley's $e$-Positivity of Claw-Contractible-Free Graphs. This is joint work with Angele Hamel and Stephanie van Willigenburg. |
Sara Billey, Combinatorics Seminar, Mathematics Department, University of Washington |
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