PreprintCC BY 4.0arXiv
Regularity of Totally Nonnegative Wonderful Compactification
Abstract
Let G be a split real semisimple group of adjoint type. We prove that the cellular decomposition of the totally nonnegative part of its wonderful compactification is a regular CW complex, confirming a conjecture of Galashin, Karp, and Lam. In particular, the closure of every cell is homeomorphic to a closed ball. The proof combines a Bruhat atlas compatible with total positivity and a CL-labeling of the augmented face poset. The atlas models the strata locally with open Richardson varieties in the flag variety of a larger Kac-Moody group and identifies their totally nonnegative cells.
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BibTeX
@misc{he2026regularity,
title = {{Regularity of Totally Nonnegative Wonderful Compactification}},
author = {Xuhua He and Kaitao Xie},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16332},
eprint = {2610.16332},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16332},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Regularity of Totally Nonnegative Wonderful Compactification
AU - Xuhua He
AU - Kaitao Xie
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.16332
UR - https://arxiv.org/abs/2610.16332
AB - Let G be a split real semisimple group of adjoint type. We prove that the cellular decomposition of the totally nonnegative part of its wonderful compactification is a regular CW complex, confirming a conjecture of Galashin, Karp, and Lam. In particular, the closure of every cell is homeomorphic to a closed ball. The proof combines a Bruhat atlas compatible with total positivity and a CL-labeling of the augmented face poset. The atlas models the strata locally with open Richardson varieties in the flag variety of a larger Kac-Moody group and identifies their totally nonnegative cells.
ER -