On block induction (Q6365403)

This paper generalizes a result of Okuyama discussing when a block of a subgroup induces up to a block of the group, by observing that Okuyama's arguments hold under less stringent hypotheses. This is applied to establish a necessary and sufficient condition for a block of defect zero of a subgroup to induce to a block of the group. Another application concerns block induction from a normal subgroup.