Exact dg structures are classified intrinsically by bi-Serre subcategories
Abstract
The aim of this article is to leverage Enomoto's classification of exact structures to the dg level. Let π be a connective additive idempotent complete dg category. We establish an intrinsic Enomoto-type classification of exact dg structures on π in terms of bi-Serre subcategories in tr(π). Our proof is a direct dg argument based on dg totalizations of $3$-term complexes and dg duality, rather than a reduction to the greatest exact dg structure and the classification of its substructures. As a consequence, we establish a bijection between exact dg structures on π and bi-Serre subcategories in tr(π). Moreover, this bijection is an isomorphism of posets and yields a complete lattice structure on the class of exact dg structures on π. In particular, we provide another construction of Rump--Chen's greatest exact dg structure on π.
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BibTeX
@misc{ogawa2026exact,
title = {{Exact dg structures are classified intrinsically by bi-Serre subcategories}},
author = {Yasuaki Ogawa},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25583},
eprint = {2609.25583},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25583},
}
RIS
TY - UNPB
TI - Exact dg structures are classified intrinsically by bi-Serre subcategories
AU - Yasuaki Ogawa
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.25583
UR - https://arxiv.org/abs/2609.25583
AB - The aim of this article is to leverage Enomoto's classification of exact structures to the dg level. Let π be a connective additive idempotent complete dg category. We establish an intrinsic Enomoto-type classification of exact dg structures on π in terms of bi-Serre subcategories in tr(π). Our proof is a direct dg argument based on dg totalizations of $3$-term complexes and dg duality, rather than a reduction to the greatest exact dg structure and the classification of its substructures. As a consequence, we establish a bijection between exact dg structures on π and bi-Serre subcategories in tr(π). Moreover, this bijection is an isomorphism of posets and yields a complete lattice structure on the class of exact dg structures on π. In particular, we provide another construction of Rump--Chen's greatest exact dg structure on π.
ER -