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Geometry of Peterson Schubert calculus in type a and left-right diagrams. (English) Zbl 07841438

Summary: We introduce an additive basis of the integral cohomology ring of the Peterson variety which reflects the geometry of certain subvarieties of the Peterson variety. We explain the positivity of the structure constants from a geometric viewpoint, and provide a manifestly positive combinatorial formula for them. We also prove that our basis coincides with the additive basis introduced by Harada-Tymoczko.

MSC:

14M15 Grassmannians, Schubert varieties, flag manifolds
05E40 Combinatorial aspects of commutative algebra

References:

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