Glauberman correspondents and extensions of nilpotent block algebras

The main purpose of this paper is to prove that the extensions of a nilpotent block algebra and its Glauberman correspondent block algebra are Morita equivalent under an additional group-theoretic condition. In particular, Harris and Linckelman’s theorem and Koshitani and Michler’s theorem are covered. The ingredient to carry out our purpose is the two main results in K"ulshammer and Puig’s work “Extensions of nilpotent blocks”; we actually revisited them, giving completely new proofs of both and slightly improving the second one.