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Geometry of the twin manifolds of regular semisimple Hessenberg varieties and unicellular LLT polynomials. (English) Zbl 07873571

Summary: Recently, Masuda-Sato and Precup-Sommers independently proved an LLT version of the Shareshian-Wachs conjecture, which says that the Frobenius characteristics of the cohomology of the twin manifolds of regular semisimple Hessenberg varieties are unicellular LLT polynomials. The purpose of this paper is to study the geometry of twin manifolds and we prove that they are related by explicit blowups and fiber bundle maps. Upon taking their cohomology, we obtain a direct proof of the modular law which establishes the LLT Shareshian-Wachs conjecture.

MSC:

14M15 Grassmannians, Schubert varieties, flag manifolds
05E10 Combinatorial aspects of representation theory

References:

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