Symbolic Calculus on a Banach Algebra of Continuous Functions

The symbolic calculus on Banach algebras of continuous functions and related spaces is studied. In particular, functions operating on the real part of the algebra are considered. The main tool in this paper is an ultraseparation argument. As a consequence it is shown, for example, that tp on [0, 1) for any p with 0 < p < 1 does not operate on the real part of a Banach function algebra on a compact Hausdorff space unless the algebra contains every continuous function.