Let R be a left and right Noetherian ring and n, k be any non-negative integers. R is said to satisfy the Auslander-type condition Gn(k) if the right fiat dimension of the (i + 1)-th term in a minimal injective resolution of RR is at most i + k for any 0 ≤ i ≤ n - 1. In this paper, we prove that R is Gn(k) if and only if so is a lower triangular matrix ring of any degree t over R.
We introduce and study the relative lett derive functor Torn(£,£1) category, which unifies several related left derived functors. Then we give some criteria for computing the -resolution dimensions of modules in terms of the properties of Torn(£,£1) . We also construct a complete and hereditary cotorsion pair relative to balanced pairs. Some known results are obtained as corollaries.