Projective dimensions in almost split sequences
by
Dag Madsen
NTNU, Trondheim, Norway

Let \Lambda be an artin algebra and denote by mod\Lambda the category of finitely generated \Lambda-modules. When 0 --> A --> B --> C --> 0 is an exact sequence in mod\Lambda, we have pd B <= max{ pd A, pd C}. If the sequence is split, equality holds. We will discuss under which conditions the equality holds for almost split sequences (Auslander-Reiten sequences) in mod\Lambda.

Date received: July 17, 2000