diff --git a/content/sets-functions-relations/size-of-sets/reduction-alt.tex b/content/sets-functions-relations/size-of-sets/reduction-alt.tex index b9f08ec2..09807d97 100644 --- a/content/sets-functions-relations/size-of-sets/reduction-alt.tex +++ b/content/sets-functions-relations/size-of-sets/reduction-alt.tex @@ -46,7 +46,7 @@ \end{prob} \begin{proof}[Proof of {\olref[nen-alt]{thm:nonenum-pownat}} by reduction] -For reductio, suppose that $\Pow{\Nat}$ is !!{enumerable}, and thus that +For a reduction, suppose that $\Pow{\Nat}$ is !!{enumerable}, and thus that there is an enumeration of it, $N_{1}$, $N_{2}$, $N_{3}$, \dots Define the function $f \colon \Pow{\Nat} \to \Bin^\omega$ by letting @@ -62,8 +62,8 @@ It is also !!{surjective}: every string of $0$s and $1$s corresponds to some set of natural numbers, namely the one which has as its -members those natural numbers corresponding to the places where the string -has~$1$s. More precisely, if $s \in \Bin^\omega$, then define $N +members those natural numbers corresponding to the places where the string +contains a~$1$s. More precisely, if $s \in \Bin^\omega$, then define $N \subseteq \Nat$ by: \[ N = \Setabs{n \in \Nat}{s(n) = 1}