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### Horizontal-strip LLT polynomials

**Algebra & Discrete Mathematics**

Speaker: | Foster Tom, UC Berkeley |

Related Webpage: | https://math.berkeley.edu/~ftom/ |

Location: | MSB 1147 + Zoom (livestream) |

Start time: | Mon, Nov 29 2021, 11:00AM |

Lascoux, Leclerc, and Thibon defined a remarkable family of symmetric functions that are $q$-deformations of products of skew Schur functions. These LLT polynomials $G_\lambda(x;q)$ can be indexed by a tuple $\lambda$ of skew diagrams. When each skew diagram is a row, we define a weighted graph $\Pi(\lambda)$. We show that a horizontal-strip LLT polynomial is determined by this weighted graph. When $\Pi(\lambda)$ has no triangles, we establish a combinatorial Schur expansion of $G_\lambda(x;q)$. We also explore a connection to extended chromatic symmetric functions.