A Krause-type recollement for Q-shaped derived categories
Abstract
Let k be a commutative noetherian hereditary ring and let Q be a small, Hom-finite, locally bounded k-linear category admitting a Serre functor and satisfying the strong retraction property, with nilpotent pseudo-radical. For every k-algebra A, we construct a recollement of the Q-shaped homo?topy category KQ(A Inj) of objectwise injective Q-shaped modules by its full subcategory Kac Q (A Inj) of exact objects and the Q-shaped derived category DQ(A). The construction uses complete hereditary cotorsion pairs and does not require A to be noetherian. If A is left noetherian, both KQ(A Inj) and Kac Q (A Inj) are compactly generated by special preenvelopes of finitely generat?ed stalk modules. We identify (Kac Q (A Inj))c with the idempotent completion of (KQ(A Inj))c/LI ((DQ(A))c ), where LI is the fully faithful left adjoint of the localization. This paper builds on and generalizes works of Krause and Liu
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BibTeX
@misc{ma2026krausetype,
title = {{A Krause-type recollement for Q-shaped derived categories}},
author = {Yajun Ma and Peiru Yang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21507},
eprint = {2610.21507},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21507},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Krause-type recollement for Q-shaped derived categories
AU - Yajun Ma
AU - Peiru Yang
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21507
UR - https://arxiv.org/abs/2610.21507
AB - Let k be a commutative noetherian hereditary ring and let Q be a small, Hom-finite, locally bounded k-linear category admitting a Serre functor and satisfying the strong retraction property, with nilpotent pseudo-radical. For every k-algebra A, we construct a recollement of the Q-shaped homo?topy category KQ(A Inj) of objectwise injective Q-shaped modules by its full subcategory Kac Q (A Inj) of exact objects and the Q-shaped derived category DQ(A). The construction uses complete hereditary cotorsion pairs and does not require A to be noetherian. If A is left noetherian, both KQ(A Inj) and Kac Q (A Inj) are compactly generated by special preenvelopes of finitely generat?ed stalk modules. We identify (Kac Q (A Inj))c with the idempotent completion of (KQ(A Inj))c/LI ((DQ(A))c ), where LI is the fully faithful left adjoint of the localization. This paper builds on and generalizes works of Krause and Liu
ER -