[18] Let be a semimeasure over B. Show that if is computable, then we can find an algorithm to compute (x) and

[18] Let μ be a semimeasure over B∗. Show that if μ is computable, then we can find an algorithm to compute μ(x) and 

b∈B μ(xb), for all x ∈ B∗, to any degree of accuracy.

Comments. These properties are implicitly used throughout Section 4.5 on continuous semimeasures. Source: [V.G. Vovk, Soviet Math. Dokl., 35(1987), 656–660].