Dualizable and semi-flat objects in abstract module categories
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Dualizable and semi-flat objects in abstract module categories. / Bak, Rune Harder.
I: Mathematische Zeitschrift, Bind 296, Nr. 1-2, 2020, s. 353-371.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Dualizable and semi-flat objects in abstract module categories
AU - Bak, Rune Harder
PY - 2020
Y1 - 2020
N2 - In this paper, we define what it means for an object in an abstract module category to be dualizable and we give a homological description of the direct limit closure of the dualizable objects. Our description recovers existing results of Govorov and Lazard, Oberst and Röhrl, and Christensen and Holm. When applied to differential graded modules over a differential graded algebra, our description yields that a DG-module is semi-flat if and only if it can be obtained as a direct limit of finitely generated semi-free DG-modules. We obtain similar results for graded modules over graded rings and for quasi-coherent sheaves over nice schemes.
AB - In this paper, we define what it means for an object in an abstract module category to be dualizable and we give a homological description of the direct limit closure of the dualizable objects. Our description recovers existing results of Govorov and Lazard, Oberst and Röhrl, and Christensen and Holm. When applied to differential graded modules over a differential graded algebra, our description yields that a DG-module is semi-flat if and only if it can be obtained as a direct limit of finitely generated semi-free DG-modules. We obtain similar results for graded modules over graded rings and for quasi-coherent sheaves over nice schemes.
KW - Cotorsion pairs
KW - Differential graded algebras and modules
KW - Direct limit closure
KW - Dualizable objects
KW - Locally finitely presented categories
KW - Semi-flat objects
UR - http://www.scopus.com/inward/record.url?scp=85084216507&partnerID=8YFLogxK
U2 - 10.1007/s00209-020-02501-z
DO - 10.1007/s00209-020-02501-z
M3 - Journal article
AN - SCOPUS:85084216507
VL - 296
SP - 353
EP - 371
JO - Mathematische Zeitschrift
JF - Mathematische Zeitschrift
SN - 0025-5874
IS - 1-2
ER -
ID: 242709059