
arXiv: 1306.6788
Recently, tilting and cotilting classes over commutative noetherian rings have been classified in arXiv:1203.0907. We proceed and, for each n-cotilting class C, construct an n-cotilting module inducing C by an iteration of injective precovers. A further refinement of the construction yields the unique minimal n-cotilting module inducing C. Finally, we consider localization: a cotilting module is called ample, if all of its localizations are cotilting. We prove that for each 1-cotilting class, there exists an ample cotilting module inducing it, but give an example of a 2-cotilting class which fails this property.
18 pages; version 2: minor corrections
cotilting class, Structure, classification theorems for modules and ideals in commutative rings, Homological functors on modules of commutative rings (Tor, Ext, etc.), tilting module, tilting class, Mathematics - Rings and Algebras, Module categories and commutative rings, Mathematics - Commutative Algebra, Commutative Algebra (math.AC), Noetherian ring, injective precover, Rings and Algebras (math.RA), 13C05 (Primary) 13C60, 13D07 (Secondary), FOS: Mathematics, pure injective module, cotilting module, Representation Theory (math.RT), Mathematics - Representation Theory
cotilting class, Structure, classification theorems for modules and ideals in commutative rings, Homological functors on modules of commutative rings (Tor, Ext, etc.), tilting module, tilting class, Mathematics - Rings and Algebras, Module categories and commutative rings, Mathematics - Commutative Algebra, Commutative Algebra (math.AC), Noetherian ring, injective precover, Rings and Algebras (math.RA), 13C05 (Primary) 13C60, 13D07 (Secondary), FOS: Mathematics, pure injective module, cotilting module, Representation Theory (math.RT), Mathematics - Representation Theory
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