Good tilting modules and recollements of derived module categories
Chen, Hongxing ; Xi, Changchang
arXiv, 1012.2176 / Harvested from arXiv
Let $T$ be an infinitely generated tilting module of projective dimension at most one over an arbitrary associative ring $A$, and let $B$ be the endomorphism ring of $T$. In this paper, we prove that if $T$ is good then there exists a ring $C$, a homological ring epimorphism $B\ra C$ and a recollement among the (unbounded) derived module categories $\D{C}$ of $C$, $\D{B}$ of $B$, and $\D{A}$ of $A$. In particular, the kernel of the total left derived functor $T\otimes_B^{\mathbb L}-$ is triangle equivalent to the derived module category $\D{C}$. Conversely, if the functor $T\otimes_B^{\mathbb L}-$ admits a fully faithful left adjoint functor, then $T$ is a good tilting module. We apply our result to tilting modules arising from ring epimorphisms, and can then describe the rings $C$ as coproducts of two relevant rings. Further, in case of commutative rings, we can weaken the condition of being tilting modules, strengthen the rings $C$ as tensor products of two commutative rings, and get similar recollements. Consequently, we can produce examples (from commutative algebra and $p$-adic number theory, or Kronecker algebra) to show that two different stratifications of the derived module category of a ring by derived module categories of rings may have completely different derived composition factors (even up to ordering and up to derived equivalence),or different lengths. This shows that the Jordan-H\"older theorem fails even for stratifications by derived module categories, and also answers negatively an open problem by Angeleri-H\"ugel, K\"onig and Liu.
Publié le : 2010-12-09
Classification:  Mathematics - Representation Theory,  Mathematics - Rings and Algebras
@article{1012.2176,
     author = {Chen, Hongxing and Xi, Changchang},
     title = {Good tilting modules and recollements of derived module categories},
     journal = {arXiv},
     volume = {2010},
     number = {0},
     year = {2010},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1012.2176}
}
Chen, Hongxing; Xi, Changchang. Good tilting modules and recollements of derived module categories. arXiv, Tome 2010 (2010) no. 0, . http://gdmltest.u-ga.fr/item/1012.2176/