Corrections |

*Hall polynomials for the representation-finite hereditary algebras.*Adv. Math. 84 (1990), 137-178

p.138: The Hall polynomial φ_{11}is T(T^{3}-2T^{2}-T+3) as calculated on page 171.- Preprint:
*Morphisms determined by objects: The case of modules over artin algebras*

The remark after Lemma 2 has to be corrected. Let L be an indecomposable summand L of the kernel K of a map f:X -> Y. It is possible that the composition of the embeddings L -> K -> X is non-split, whereas L is not a summand of an intrinsic kernel of f. As an example, take the quiver o <- o <- o, take X = (kkk)\oplus (0k0), Y = (00k) and f the canonical projection. Then the kernel K is (kk0)\oplus (0k0), the intrinsic kernel is (kk0)\oplus (000) (there is just one). The kernel has also a direct decomposition L\oplus (0k0) with L \neq (kk0), say L being generated by the element (0,(1,1),0) in (kk0)\oplus (0k0). Then the composition of the embeddings L -> K -> X is not a split monomorphism, but L is not a direct summand of any intinsic kernel.

- Infinite length modules. Some examples as introduction. In: Infinite length modules. Trends in Mathematics. Birkhäuser Verlag (2000)
- Infinite dimensional representations of finite dimensional hereditary algebras. Symposia Math. 23 (1979), 321-412.
- (mit D. Vossieck) Hammocks. Proc. London Math. Soc. (3) 54 (1987), 216-246

p.216, line -4: replace m(y,x) by m(x,y).

p.217, line 15 (displayed formula): replace + by -. -
Fahr-Ringel: A partition formula for Fibonacci numbers,

Journal of Integer Sequences, Vol.11 (2008), Article 08.1.4. - Iyama's finiteness theorem via strongly quasi-hereditary algebras

Claus Michael Ringel Last modified: Wed Jul 15 09:58:22 CEST 2009