Mi MWE es:
\documentclass{book}
\usepackage{multicol,shortlst}
\makeatletter
\setlength{\columnsep}{35pt}%% Space between columns
\setlength{\columnseprule}{2pt}%% Width of rule between columns
\renewcommand{\theenumi}{\arabic{enumi}}
\renewcommand{\labelenumi}{\theenumi}
\renewcommand{\theenumii}{\alph{enumii}}
\renewcommand{\labelenumii}{\theenumii}
\renewcommand{\theenumiii}{\roman{enumiii}}
\renewcommand{\labelenumiii}{{\theenumiii}}
\renewenvironment{shortenumerate}[1][\hbox to \shortitemwidth{\hfil}]{%
\setlength\shortitemwidth{45pt} %% Balaji added
\ifnum \@enumdepth >\thr@@\@toodeep\let\endsh@rtitem\relax\else
\ifx\item\sh@rtitem\sh@rtnesterr\let\endsh@rtitem\relax\else
\advance\@enumdepth\@ne
\edef\@enumctr{enum\romannumeral\the\@enumdepth}%
\settowidth\shortitemwidth{#1}%
\list{}{\addtolength\leftmargin\itemindent
\addtolength\leftmargin{-\labelwidth}%
\addtolength\leftmargin{-\labelsep}%
\addtolength\leftmargin{-7pt} %% Balaji added
\addtolength\labelsep{-5pt} %% Balaji added
\addtolength\itemsep{0pt} %% Balaji added
\setlength\itemindent\z@}%
\item\relax
\@rightskip\@flushglue \rightskip\@rightskip
\let\endsh@rtitem\noindent
\let\item\sh@rtitem
\usecounter{\@enumctr}%
\def\@itemlabel{\csname label\@enumctr \endcsname}%
\fi\fi\ignorespaces}%
{\endsh@rtitem\endlist}
\makeatother
\setcounter{chapter}{1}
\begin{document}
\section{shortlist with 3 enumerate}
\begin{multicols}{2}
\begin{enumerate}
\item The values of should be about $-4$, $-3$. The graph of $y=x$ should approximate a line of gradient~2.
\item The values of should be 0. The graph of $y=x$ is a parabola crossing the $x=-2$ and $x=2$.
\item
\begin{shortenumerate}
\item 3
\item $-7$
\item 5
\item $-3$
\item $\frac{1}{2}$
\item 0
\end{shortenumerate}
\item
\item
\begin{shortenumerate}
$4 +h$, $f'(2) =4$
$2h +3$, $f'(0) =3$
$-6 +h$, $f'(-1) =-6$
\end{shortenumerate}
\item
\begin{shortenumerate}
\item $2x +h -6$, $=2x -6$.
\item It is a concave-up parabola with $x=0$\break and $x=6$.
\item $f'(0) =-6$, $f'(6) =6$.
\item $f'(3) =0$.
\end{shortenumerate}
\item
\begin{shortenumerate}
\item $8 -2x -h$, $=8 -2x$
\item It is a concave-down parabola with $x=0$ and $x=8$.
\item $f'(0) =8$, $f'(8) =-8$.
\item $f'(4) =0$.
\end{shortenumerate}
\end{enumerate}
\end{multicols}
\end{document}
Me gustaría obtener la lista árabe primero, la lista alfa en segundo lugar y la lista romana en tercer lugar. Entre el número arábigo y el número alfa hay un espacio fijo. El número alfa y el número romano también son espacios fijos. \breakTampoco funciona en \item. La alineación se muestra a continuación:
El resultado esperado es:
