How to set a list in two columns?

Question

I face the following

Here all are appears below one by one. Actually I want, the last five are appears in the RHS of the first five. That is , how to align equally in the middle for a good look?

For this, I typed

  \begin{enumerate}
  \item $f:\Bbb R \to \Bbb R, x \mapsto \ln x$ 
  \item $f:\Bbb R \to \Bbb R, x \mapsto [x]$
  \item $f:\Bbb R \to \Bbb R, x \mapsto \frac{1}{x}$
  \item $f:\Bbb R \to \Bbb R, x \mapsto \tan x$ 
  \item $f:\Bbb R \to \Bbb R, x \mapsto \sqrt{x}$
  \item $f:\Bbb N \to \Bbb Z, x \mapsto 5$
  \item $f:\Bbb R \to \Bbb R, x \mapsto e^x$
  \item $f:\Bbb N \to \Bbb N, x \mapsto 2^x$
  \item $f:\Bbb R \to \Bbb R, x \mapsto \sin x$
  \item $f:\Bbb R \to \Bbb R, x \mapsto x^2$
  \end{enumerate}

Any help?

The command \Bbb has been deprecated for more than 20 years. The correct call is \mathbb{R}. Also, you should have two formulas per line, like $f\colon\mathbb{R}\to\mathbb{R}$, $x\mapsto\log x$. — egreg, Jul 01 '19 at 16:30
In my opinion, it's more sensible to have the numbering horizontally first, then vertically. — Bernard, Jul 01 '19 at 18:09

score 4 · Accepted Answer · 2019-07-01T16:31:51.240

One way is to use multicols and to resume numbering at 5 in the second column. lipsum is just to show it merges into surrounding text.

\documentclass{article} 
\usepackage{amssymb}
\usepackage{multicol}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{multicols}{2}
\begin{enumerate}
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \ln x$ 
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto [x]$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \frac{1}{x}$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \tan x$ 
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \sqrt{x}$
\end{enumerate}
\columnbreak
\begin{enumerate}  \setcounter{enumi}{5}
  \item $f:\mathbb{N} \to \mathbb{Z}, x \mapsto 5$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto e^x$
  \item $f:\mathbb{N} \to \mathbb{N}, x \mapsto 2^x$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \sin x$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto x^2$
  \end{enumerate}
\end{multicols}  
\lipsum[2]
\end{document}

Or without lipsum and more importantly with @egreg's hint.

\documentclass{article} 
\usepackage{amssymb}
\usepackage{multicol}
\begin{document}
\begin{multicols}{2}
\begin{enumerate}
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \ln x$ 
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto [x]$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \frac{1}{x}$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \tan x$ 
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \sqrt{x}$
\columnbreak
  \item $f:\mathbb{N} \to \mathbb{Z}, x \mapsto 5$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto e^x$
  \item $f:\mathbb{N} \to \mathbb{N}, x \mapsto 2^x$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto \sin x$
  \item $f:\mathbb{R} \to \mathbb{R}, x \mapsto x^2$
  \end{enumerate}
\end{multicols}  
\end{document}

sir.... before and after the equtions, texts like Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, ..... are appears. How to remove this? — Chinz, Jul 01 '19 at 16:28
@egreg That's a very good point. I was not aware of that! Mille grazie! — , Jul 01 '19 at 16:30
Since all ten items have the same height, you don't even need the \columnbreak statement. :-) On a different subject: In all ten items, \colon would be preferable to :, as the latter has math status "math-rel". — Mico, Jul 01 '19 at 17:18
@Mico Thanks! I didn't know that either. (IMHO an even bigger improvement would be to end each equation with a semicolon and the others with a period, but different users have different attitudes. I share Barbara Beeton's opinion that equations also require punctuation.) — , Jul 01 '19 at 17:36

How to set a list in two columns?

1 Answers1