4 research outputs found
Strongly tilting truncated path algebras
For any truncated path algebra Î, we give a structural description of the modules in the categories
{\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}
and
{\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}
, consisting of the finitely generated (resp. arbitrary) Î-modules of finite projective dimension. We deduce that these categories are contravariantly finite in Îâmod and Î-Mod, respectively, and determine the corresponding minimal
{\mathcal{P}^{<\infty}}
-approximation of an arbitrary Î-module from a projective presentation. In particular, we explicitly constructâbased on the Gabriel quiver Q and the Loewy length of Îâthe basic strong tilting module Î
T (in the sense of Auslander and Reiten) which is coupled with
{\mathcal{P}^{<\infty}(\Lambda\text{-}{\rm mod})}
in the contravariantly finite case. A main topic is the study of the homological properties of the corresponding tilted algebra
, such as its finitistic dimensions and the structure of its modules of finite projective dimension. In particular, we characterize, in terms of a straightforward condition on Q, the situation where the tilting module
is strong over
as well. In this Î-
-symmetric situation, we obtain sharp results on the submodule lattices of the objects in
{\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}
, among them a certain heredity property; it entails that any module in
{\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}
is an extension of a projective module by a module all of whose simple composition factors belong to
{\mathcal{P}^{<\infty}({\rm Mod}\text{-}\tilde{\Lambda})}