\emph{another function}, boolean negation, and the vector of booleans,
\hs{xs}. The \hs{map} function applies the negation function to all the
elements in the vector.
The \hs{map} function is called a higher-order function, since it takes
another function as an argument. Also note that \hs{map} is again a
\emph{another function}, boolean negation, and the vector of booleans,
\hs{xs}. The \hs{map} function applies the negation function to all the
elements in the vector.
The \hs{map} function is called a higher-order function, since it takes
another function as an argument. Also note that \hs{map} is again a