Invariant Subgroups in Rings with Involution
Invariant Subgroups in Rings with Involution
Let R be a ring with involution*. In this paper, we study additive subgroups A of R which are invariant under all mappings of the form ϕ x : a → xax*. That is, xAx* ⊆ A for all x ∈ R. Obvious examples of such subgroups A are ideals …