Degenerations for Selfinjective Algebras of Treeclass D n

Let Λ be a connected representation finite selfinjective algebra. According to G. Zwara the partial orders ⩽ ext and ⩽ deg on the isomorphism classes of d ‐dimensional Λ‐modules are equivalent if and only if the stable Auslander–Reiten quiver Γ Λ of Λ is not isomorphic to ZD 3 m /τ 2 m −1 for all m ⩾ 2. The paper describes all minimal degenerations M ⩽ deg N with M ≰ ext N in the case when Γ Λ ≅ ZD 3 m /τ 2 m −1 for some m ⩾ 2.