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Permutation twisted cohomology, reduced and immersed
Abstract
In this paper, we introduce a `reduced' form of permutation twisted cohomology as introduced by Balmer--Gallauer and further developed by Miller. This ring is bigraded by a well-chosen choice of endotrivial complex, rather than multigraded by a family of endotrivial complexes. The Balmer spectrum of the small derived category of permutation modules openly immerses into the homogeneous spectrum of this ring. We also show that for p-groups, Miller's `remixed' twisted cohomology ring also admits the Balmer spectrum as an open subspace, and confirm in both cases it can be upgraded to have Dirac scheme structure; furthermore, we prove that the two open covers witnessing this are in general different.
Related
BibTeX
@misc{gomez2026permutation,
title = {{Permutation twisted cohomology, reduced and immersed}},
author = {Juan Omar Gómez and Sam K. Miller},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40602},
eprint = {2610.40602},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40602},
}
RIS
TY - UNPB
TI - Permutation twisted cohomology, reduced and immersed
AU - Juan Omar Gómez
AU - Sam K. Miller
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40602
UR - https://arxiv.org/abs/2610.40602
AB - In this paper, we introduce a `reduced' form of permutation twisted cohomology as introduced by Balmer--Gallauer and further developed by Miller. This ring is bigraded by a well-chosen choice of endotrivial complex, rather than multigraded by a family of endotrivial complexes. The Balmer spectrum of the small derived category of permutation modules openly immerses into the homogeneous spectrum of this ring. We also show that for p-groups, Miller's `remixed' twisted cohomology ring also admits the Balmer spectrum as an open subspace, and confirm in both cases it can be upgraded to have Dirac scheme structure; furthermore, we prove that the two open covers witnessing this are in general different.
ER -