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arXiv · 1906.08118

On the coproduct in affine Schubert calculus

Thomas Lam·Seung Jin Lee·Mark Shimozono
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Abstract

The cohomology of the affine flag variety of a complex reductive group is a comodule over the cohomology of the affine Grassmannian. We give positive formulae for the coproduct of an affine Schubert class in terms of affine Stanley classes and finite Schubert classes, in (torus-equivariant) cohomology and K-theory. As an application, we deduce monomial positivity for the affine Schubert polynomials of the second author.

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Thomas Lam, Seung Jin Lee, Mark Shimozono. 2020-09-20. On the coproduct in affine Schubert calculus. https://arxiv.org/abs/1906.08118

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