English

Jordan $*-$homomorphisms between unital $C^*-$algebras

Operator Algebras 2009-08-04 v1

Abstract

Let A,BA,B be two unital CC^*-algebras. We prove that every almost unital almost linear mapping h:ABh:A\longrightarrow B which satisfies h(3nuy+3nyu)=h(3nu)h(y)+h(y)h(3nu)h(3^nuy+3^nyu) = h(3^nu)h(y)+h(y)h(3^nu) for all uU(A)u\in U(A), all yAy\in A, and all n=0,1,2,...n = 0, 1, 2,..., is a Jordan homomorphism. Also, for a unital CC^*-algebra AA of real rank zero, every almost unital almost linear continuous mapping h:ABh:A\longrightarrow B is a Jordan homomorphism when h(3nuy+3nyu)=h(3nu)h(y)+h(y)h(3nu)h(3^nuy+3^nyu) = h(3^nu)h(y)+h(y)h(3^nu) holds for all uI1(Asa)u\in I_1(A_{sa}), all yA,y\in A, and all n=0,1,2,... n = 0, 1, 2,... ~. Furthermore, we investigate the Hyers--Ulam--Rassias stability of Jordan *-homomorphisms between unital CC^*-algebras by using the fixed points methods.

Keywords

Cite

@article{arxiv.0908.0070,
  title  = {Jordan $*-$homomorphisms between unital $C^*-$algebras},
  author = {M. Eshaghi Gordji},
  journal= {arXiv preprint arXiv:0908.0070},
  year   = {2009}
}