dmtcs:2835 -
Discrete Mathematics & Theoretical Computer Science,
January 1, 2010,
DMTCS Proceedings vol. AN, 22nd International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC 2010)
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https://doi.org/10.46298/dmtcs.2835
Bruhat order, rationally smooth Schubert varieties, and hyperplane arrangementsArticle
Authors: Suho Oh 1; Hwanchul Yoo 1
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Suho Oh;Hwanchul Yoo
1 Department of Mathematics [MIT]
We link Schubert varieties in the generalized flag manifolds with hyperplane arrangements. For an element of a Weyl group, we construct a certain graphical hyperplane arrangement. We show that the generating function for regions of this arrangement coincides with the Poincaré polynomial of the corresponding Schubert variety if and only if the Schubert variety is rationally smooth.