In functional analysis, a Banach function algebra on a compact Hausdorff space X is unital subalgebra, A, of the commutative C*-algebra C(X) of all continuous, complex-valued functions from X, together with a norm on A that makes it a Banach algebra.

A function algebra is said to vanish at a point p if f(p. A function algebra separates points.

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Theorem: A Banach function algebra is semisimple (that is its Jacobson radical is equal to zero) and each commutative unital, semisimple Banach algebra is isomorphic (via the Gelfand transform) to a Banach function algebra on its character space (the space of algebra homomorphisms from A into the complex numbers given the relative weak* topology).

is called a uniform algebra. Uniform algebras are an important special case of Banach function algebras.

References

• Andrew Browder (1969) Introduction to Function Algebras, W. A. Benjamin

• H.G. Dales (2000) Banach Algebras and Automatic Continuity, London Mathematical Society Monographs 24, Clarendon Press

• Graham Allan & H. Garth Dales (2011) Introduction to Banach Spaces and Algebras, Oxford University Press