Published as

T. Everaert and T. Van der Linden,Additional commentsBaer invariants in semi-abelian categories I: General theory, Theory Appl. Categ.12(2004), no. 1, 1-33.

In Section 3, the context is not quite right for the stated results. It would probably be better to assume that the surrounding categoryAis pointed, exact and protomodular from the start. In particular, Proposition 3.9 actually needs that every regular epimorphism is normal, which is a consequence of protomodularity. This defect is repaired inT. Van der Linden,There the context is also slightly enlarged (quasi-pointed instead of pointed).Homology and homotopy in semi-abelian categories, Ph.D. Thesis, Vrije Universiteit Brussel, 2006, arXiv:math/0607100

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