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On $$t$$-structures and torsion theories induced by compact objects. (English) Zbl 1006.18011
The authors present in this paper a new approach and a generalisation of J. Rickard’s theory of tilting complexes. Rickard’s theory describes equivalences between derived module categories. The authors study in the present paper the relation with $$t$$-structures of triangulated categories, torsion theories of abelian categories, and the consequences for tilting theory given by two-term tilting complexes. The restriction to two-term complexes seems to be motivated by Okuyama’s method for proving Broué’s conjecture. Okuyama’s method uses two-term tilting complexes, and is at the moment the most successful way to prove the conjecture in examples.
The authors first show that for a compact object $$C$$ in a triangulated category so that for positive $$n$$, $$\text{Hom}(C,C[n])=0$$, $$C$$ generates a $$t$$-structure so that $$\text{Hom}(C,-)$$ induces an equivalence between its core and the endomorphism ring of $$C$$. In case of the derived category of an abelian category $$A$$ and $$C$$ being a two-term complex, the authors show when $$C$$ defines a torsion theory of $$A$$. The condition is related to the condition of being a tilting complex, but is weaker. As a consequence, if this happens the authors deduce an equivalence between the endomorphism ring of $$C$$ and the core of the $$t$$-structure, as well as a torsion theory for the core. Finally, the authors make the case of a module category of an algebra, in particular of an Artin algebra, more precise. They provide an explicit interesting example for these phenomenons.

##### MSC:
 18E30 Derived categories, triangulated categories (MSC2010) 16S90 Torsion theories; radicals on module categories (associative algebraic aspects) 18E40 Torsion theories, radicals 16G10 Representations of associative Artinian rings
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