First Hochschild cohomology group and stable equivalence classification of Morita type of some tame symmetric algebras

Abstract

We use the dimension and the Lie algebra structure of the first Hochschild cohomology group to distinguish some algebras of dihedral, semi-dihedral and quaternion type up to stable equivalence of Morita type. In particular, we complete the classification of algebras of dihedral type that was mostly determined by Zhou and Zimmermann.

Some elementary details were removed and some minor mistakes corrected. To appear in Homology, Homotopy and Applications