rleiva / NescienceBook

The Mathematics of the Unknown
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Clarify the definition of prefix-free universal Turing machine #104

Closed rleiva closed 7 months ago

rleiva commented 9 months ago

In the following definition,

\begin{definition} A \emph{prefix-free universal Turing machine} is a universal Turing machine $U:\mathcal{B}^\ast \times \mathcal{B}^\ast \rightarrow \mathcal{B}^\ast$ such that, for every $v \in \mathcal{B}^\ast$, the domain $U{v}$ is prefix-free, where $U{v}:\mathcal{B}^\ast \rightarrow \mathcal{B}^\ast$ and $U_{v}(x) = U(x, v)$ for all $x in \mathcal{B}^\ast$. \end{definition}

Write a paragraph clarifying why we have to fix the imput string $v$ in $U_{v}(x) = U(x, v)$, since this is something that might confuse some readers.

rleiva commented 7 months ago

Added a TODO in the text.