Springer fibers and the Delta Conjecture at t = 0

We introduce a family of varieties Yn,λ,s, which we call the Δ-Springer varieties, that generalize the type A Springer fibers. We give an explicit presentation of the cohomology ring H⁎(Yn,λ,s) and show that there is a symmetric group action on this ring generalizing the Springer action on the cohom...

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Published in:Advances in mathematics (New York. 1965) 2024-03, Vol.439, p.109491, Article 109491
Main Authors: Griffin, Sean T., Levinson, Jake, Woo, Alexander
Format: Article
Language:eng
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Summary:We introduce a family of varieties Yn,λ,s, which we call the Δ-Springer varieties, that generalize the type A Springer fibers. We give an explicit presentation of the cohomology ring H⁎(Yn,λ,s) and show that there is a symmetric group action on this ring generalizing the Springer action on the cohomology of a Springer fiber. In particular, the top cohomology groups are induction products of Specht modules with trivial modules. The λ=(1k) case of this construction gives a compact geometric realization for the expression in the Delta Conjecture at t=0. Finally, we generalize results of De Concini and Procesi on the scheme of diagonal nilpotent matrices by constructing an ind-variety Yn,λ whose cohomology ring is isomorphic to the coordinate ring of the scheme-theoretic intersection of an Eisenbud–Saltman rank variety and diagonal matrices.
ISSN:0001-8708
1090-2082