\documentclass[oneside,12pt]{article}
\usepackage{geometry}
\usepackage{microtype}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{enumitem}
\setlist[enumerate,1]{label=\bfseries\Alph*,align=left,leftmargin=*,
labelsep=1.5em}
\setlist[enumerate,2]{label=\arabic*.,labelindent=1em,labelsep=1.5em,
leftmargin=*}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}
\theoremstyle{definition}
\newtheorem*{sol}{Solution}
\usepackage{forest}
\forestset{
ass/.append style={
before computing xy={l=\baselineskip},
no edge
},
prooftree/.style={
for tree={
child anchor=north,
parent anchor=south
}
},
default preamble={
prooftree,
for root={baseline},
for tree={%
if n children={1}{for children={ass}}{},
math content
}
}
}
\begin{document}
\subsection*{Exercises 28}
\begin{enumerate}
\item Let's use `$\vDash$' now to abbreviate `q-entails'. Which of the
following claims are true? Provide arguments in the style of 28.2 and 28.6
to defend your answers.
\begin{enumerate}
\item $\forall x(Fx\supset Gx)\vDash\forall x(Gx\supset Fx)$
\begin{sol}
Try the following q-valuation:
\begin{quote}
Domain = all people\\
Extension of `F' = all singers\\
Extension of `G' = all people who know how to sing
\end{quote}
Then, the premiss is true, but the conclusion is false.
\end{sol}
\item $\forall x(Fx\supset Gx)\vDash\forall x(\neg Gx\supset\neg Fx)$
\begin{sol}
\begin{forest}
[$\forall x(Fx\supset Gx)$
[$\forall x$]]
\end{forest}
\end{sol}
\end{enumerate}
\end{enumerate}
\end{document}
生产
但我期望看到。
我怎样才能default preamble
应用于森林环境?