| Summary: | By the Riesz representation theorem using the Riemann-Stieltjes integral,
linear continuous functionals on the set of continuous functions from the unit
interval into the reals can either be characterized by functions of bounded
variation from the unit interval into the reals, or by signed measures on the
Borel-subsets. Each of these objects has an (even minimal) Jordan decomposition
into non-negative or non-decreasing objects. Using the representation approach
to computable analysis, a computable version of the Riesz representation
theorem has been proved by Jafarikhah, Lu and Weihrauch. In this article we
extend this result. We study the computable relation between three Banach
spaces, the space of linear continuous functionals with operator norm, the
space of (normalized) functions of bounded variation with total variation norm,
and the space of bounded signed Borel measures with variation norm. We
introduce natural representations for defining computability. We prove that the
canonical linear bijections between these spaces and their inverses are
computable. We also prove that Jordan decomposition is computable on each of
these spaces.
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