LyX is great. I use it to write everyday documents. But it seems that its environment can only have one type; different types of environments can't be mixed. For example, you can't have itemize inside a proof. If you try, either you lose the itemize, or the itemize part become outside of the proof. Can I have itemize inside proofs? You need this when making case distinctions.
[Tex/LaTex] In LyX, how to have itemize inside a proof
environmentsitemizelistslyxnesting
Related Solutions
I used the thmtools package as a front-end for amsthm in order to define a new Proof environment; the other two environments were created using \newenvironment. The Proof, claim and precondition environments use adjustwidth from the changepage package to increase the left margin. Of course, feel free to make the necessary adjustments according to your needs:
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{thmtools}
\usepackage{changepage}
\usepackage[nopar]{lipsum}% just to generate some text
\newlength\Thmindent
\setlength\Thmindent{20pt}
\newenvironment{precondition}
{\par\medskip\adjustwidth{\Thmindent}{}\normalfont\textbf{Preconditions:}\par\nobreak}
{\endadjustwidth}
\newenvironment{claim}
{\par\medskip\adjustwidth{\Thmindent}{}\normalfont\textbf{Claim:}}
{\endadjustwidth}
\declaretheoremstyle[
spaceabove=0pt,spacebelow=0pt,
preheadhook=\adjustwidth{\Thmindent}{},
prefoothook=\endadjustwidth,
headpunct=:,
numbered=no,
qed=\qedsymbol
]{proof}
\declaretheorem[style=proof]{Proof}
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\begin{document}
\begin{theorem}
\lipsum[2]
\begin{precondition}
\begin{itemize}
\item $A := \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$
\item $B := \begin{pmatrix} 2 & 2 \\ 3 & 4 \end{pmatrix}$
\item $n \in \mathbb{N}$
\end{itemize}
\end{precondition}
\begin{claim}
$\sqrt{2}\notin\mathbb{Q}$
\end{claim}
\begin{Proof}
\lipsum[2]
\end{Proof}
\end{theorem}
\end{document}
In addition to the regular lists, LyX also provides a List, which outputs a lyxlist. Similar to a description, the first input is the item label. You can't insert a display math item here but you can insert an inline math equation:
I guess you have a couple of options (without knowing exactly what the text looks like):
- Remove the List and insert the content in a regular paragraph
- Use an inline math equation rather than a display one
Best Answer
Lyx can perfectly nest environments: All you need to do is to increase the nesting depth (Edit ➔ Increase List Depth):