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CAGE: Philadelphia Area Combinatorics and Alg. Geometry Seminar

Tuesday, March 26, 2024 - 10:15am

Alex Vetter

Penn

Location

University of Pennsylvania

DRl 4C8

We show how the coeffcient of an augmented hook shapesin the expansion of a vertical strip LLT polynomials has a nice combiinatorial interpretation.  Our proof starts with the expansion of vertical strip LLT polynomials into elementary symmetric functions, whose coefficients are positive integral combinations of powers of q-1.  We then expand the powers of q-1, and also the products of elementary symmetric functions into Schur fiunctions, to get a signed expression for the Schur coefficeints. We then show (in the caser of augmentted hook shapes) how to cancel the negative terms with paired positive terms, leaving a positive expression.