Abstract

Let A be a ring with 1, C the center of A and G an inner automorphism group of A induced by {Uα in A/α in a finite group G whose order is invertible}. Let AG be the fixed subring of A under the action of G.If A is a Galcis extension of AG with Galois group G and C is the center of the subring αAGUα then A=αAGUα and the center of AG is also C. Moreover, if αAGUα is Azumaya over C, then A is a projective group ring.