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Closure relations for totally nonnegative cells in G/P

Konstanze Rietsch
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Abstract

The totally nonnegative part of a partial flag variety G/P is known to have a decomposition into semi-algebraic cells. We show that the closure of a cell is again a union of cells and give a combinatorial description of the closure relations. The totally nonnegative cells are defined by intersecting the totally nonnegative part with a certain stratification of G/P defined by Lusztig. We also verify the same closure relations for these strata.

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Konstanze Rietsch. 2005-11-10. Closure relations for totally nonnegative cells in G/P. https://arxiv.org/abs/math/0509137

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