Spatial numerical ranges of elements of
subalgebras of C0(X)
Sin-Ei Takahasi1
Received09 Jul 1998
Revised26 Jan 1999
Abstract
When A is a subalgebra of the commutative Banach algebra
C0(X) of all continuous complex-valued functions on a locally
compact Hausdorff space X, the spatial numerical range of
element of A can be described in terms of positive measures.