Published in Advances in Mathematics
Given a representation-finite algebra B and a subalgebra A of B such that the Jacobson radicals of A and B coincide, we prove that the representation dimension of A is at most three. By a result of Igusa and Todorov, this implies that the finitistic dimension of A is finite.
Published in Advances in Mathematics
By introducing a twisted Hopf algebra we unify several important objects of study. Skew derivations of such an algebra are defined and the corresponding skew differential operator algebras are studied. This generalizes results in the Weyl algebra. Applying this investigation to the twisted Ringel–Hall algebra we get, in particular, a natural realiz...
Published in Open Mathematics
In continuation of our earlier work [2] we describe the indecomposable representations and the Auslander-Reiten quivers of a family of vector space categories playing an important role in the study of domestic finite dimensional algebras over an algebraically closed field. The main results of the paper are applied in our paper [3] where we exhibit ...
Published in Open Mathematics
In the paper, we introduce a wide class of domestic finite dimensional algebras over an algebraically closed field which are obtained from the hereditary algebras of Euclidean type , n≥1, by iterated one-point extensions by two-ray modules. We prove that these algebras are domestic and their Auslander-Reiten quivers admit infinitely many nonperiodi...
Published in Advances in Mathematics
This paper concerns indecomposable preprojective modules over the path algebra of a finite connected quiver without oriented cycles. For each such module, an explicit formula in terms of the geometry of the quiver gives a unique, up to a certain equivalence, shortest (+)-admissible sequence such that the corresponding composition of reflection func...
The relative position of one subfactor of a factor has been proved quite rich since the work of Jones. We shall show that the theory of relative position of several subspaces of a separable infinite-dimensional Hilbert space is also rich. In finite-dimensonal case, Gelfand and Ponomarev gave a complete classification of indecomposable systems of fo...
Published in Advances in Mathematics
This article is to study relations between tubular algebras of Ringel and elliptic Lie algebras in the sense of Saito–Yoshii. Using the explicit structure of the derived categories of tubular algebras given by Happel–Ringel, we prove that the elliptic Lie algebra of type D 4 ( 1 , 1 ) , E 6 ( 1 , 1 ) , E 7 ( 1 , 1 ) or E 8 ( 1 , 1 ) is isomorphic t...
Published in Advances in Mathematics
We use the idea of generic extensions to investigate the correspondence between the isomorphism classes of nilpotent representations of a cyclic quiver and the orbits in the corresponding representation varieties. We endow the set M of such isoclasses with a monoid structure and identify the submonoid M c generated by simple modules. On the other h...
Published in Open Mathematics
The main aim of the paper is to classify the discrete derived categories of bounded complexes of modules over finite dimensional algebras.
Published in Advances in Mathematics
We introduce a family of algebras which are multiplicative analogues of preprojective algebras, and their deformations, as introduced by M.P. Holland and the first author. We show that these algebras provide a natural setting for the ‘middle convolution’ operation introduced by N.M. Katz in his book ‘Rigid local systems’, and put in an algebraic se...
