GELFAND–TSETLIN DEGENERATIONS OF REPRESENTATIONS AND FLAG VARIETIES

I. Makhlin

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Our main goal is to show that the Gelfand–Tsetlin toric degeneration of the type A ag variety can be obtained within a degenerate representation-theoretic framework similar to the theory of PBW degenerations. In fact, we provide such frameworks for all Gröbner degenerations intermediate between the ag variety and the GT toric variety. These degenerations are shown to induce filtrations on the irreducible representations and the associated graded spaces are acted upon by a certain associative algebra. To achieve our goal, we construct embeddings of our Gröbner degenerations into the projectivizations of said associated graded spaces in terms of this action. We also obtain an explicit description of the maximal cone in the tropical ag variety that parametrizes the Gröbner degenerations we consider. In an addendum we propose an alternative solution to the problem which relies on filtrations and gradings by non-abelian ordered semigroups.

Original languageEnglish
JournalTransformation Groups
DOIs
Publication statusPublished - 2020
Externally publishedYes

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