Self-adjointness in unitary isotopes of JB*-algebras

We prove that x is in the norm closure of invertibles whenever x is self-adjoint in some unitary isotope of a JB*-algebra. In the sequel, we investigate certain links between the elements of the unit ball which are self-adjoint in some unitary isotope of a JB*-algebra and the elements which are average of two unitaries. Received: 9 September 2005