A positive combinatorial formula for the
double Edelman-Greene coefficients
报告专家：喻天奕（加拿大蒙特利尔魁北克大学）
报告时间：2025年12月23日（周二）下午15:00-16:00
报告地点：数学学院西202
报告摘要：
Lam, Lee, and Shimozono introduced the double Stanley symmetric functions in their study of the equivariant geometry of the affine Grassmannian.They proved that the associated double Edelman-Greene coefficients, the double Schur expansion coefficients of these functions, are positive, a result later refined by Anderson. They further asked for a combinatorial proof of this positivity. In this paper, we provide the first such proof, together with a combinatorial formula that manifests the finer positivity established by Anderson. Our formula is built from two combinatorial models: bumpless pipedreams and increasing chains in the Bruhat order. The proof relies on three key ingredients: a correspondence between these two models, a natural subdivision of bumpless pipedreams, and a symmetry property of increasing chains. This talk is based on joint work with Jack Chou.
专家简介：
喻天奕，现任加拿大蒙特利尔魁北克大学博士后研究员，2024年于加州大学圣地亚哥分校获数学博士学位。研究方向为代数组合，尤其对Schubert演算感兴趣，在Trans. AMS， IMRN，Combin. Theory，Algebraic Combin. 等杂志上发表多篇高水平论文。
邀请人：范久瑜
