CHARACTERIZATIONS OF JORDAN (?)-SKEW MULTIPLICATIVE MAPS ON OPERATOR ALGEBRAS OF INDEFINITE INNER PRODUCT SPACES

Let H and K be indefinite inner product spaces. This paper shows that a bijective map Φ: B(H) → B(K) satisfies Φ(AB+ + B+A) = Φ(A)Φ(B)+ + Φ(B)+Φ(A) for every pair A,B ∈ B(H) if and only if either Φ(A) = cUAU+ for all A or Φ(A) = cUA+U+ for all A; Φ satisfies Φ(AB+A) = Φ(A)Φ(B)+Φ(A) for every pair A, B ∈ B(H) if and only if either Φ(A) = UAV for all A or Φ(A) = UA+V for all A, where A+ denotes the indefinite conjugate of A, U and V are bounded invertible linear or conjugate linear operators with U+U = c-1I and V+V = cI for some nonzero real number c.

Let H and K be indefinite inner product spaces. This paper shows that a bijective map φ：B（H） →B（K） satisfies φ（AB^＋ ＋ B^＋A） = φ（A）φ（B）^＋ ＋ φ（B）^＋φ（A） for every pair A, B ∈ B（H） if and only if either φ（A） = cUAU^＋ for all A or φ（A） = cUA^＋U^＋ for all A; φ satisfies φ（AB^＋A） = φ;（A）φ;（B）^＋φ;（A） for every pair A, B ∈ B（H） if and only if either φ（A） = UAV for all A or φ（A） = UA^＋V for all A, where At denotes the indefinite conjugate of A, U and V are bounded invertible linear or conjugate linear operators with U^tU = c^-1I and V^＋V = cI for some nonzero real number c.