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Cómo referir un elemento particular en enumthm

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Cómo referir un elemento particular en enumthm

Intenté usar LaTeX para escribir una definición. Se ve bien, pero ¿hay otra forma de evitar el elemento (d) codificado en el último elemento?

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{euscript}
\usepackage{enumitem}
\usepackage{textcomp}
\newlist{enumthm}{enumerate}{1}
\setlist[enumthm]{label=(\alph*)}
\newcommand\restr[2]{{% we make the whole thing an ordinary symbol
  \left.\kern-\nulldelimiterspace % automatically resize the bar with \right
  #1 % the function
  \vphantom{\big|} % pretend it's a little taller at normal size
  \right|_{#2} % this is the delimiter
  }}
\linespread{1.6}
\newtheorem{thm}{Theorem}[section]
\newtheorem{defn}[thm]{Definition}
\begin{document}
\begin{defn}
Let $X$ be a topological space. A \emph{presheaf} $\mathcal{F}$ (of Abelian groups) on $X$ consists an Abelian group $\mathcal{F}(U)$ for every open subset $U$ of $X$, and a group homomorphism (\emph{restriction map}) $\rho_{UV}:\mathcal{F}(U)\to\mathcal{F}(V)$ for every pair of open subsets $V\subseteq U$ which has the following properties:
\begin{enumthm}
\item $\mathcal{F}(\emptyset )=0$;
\item $\rho_{UU}=\operatorname{Id}$;
\item If we have three open subsets $W\subseteq V\subseteq U$, then $\rho_{UW}=\rho_{VW}\circ\rho_{UV}$.\\
A presheaf is said to be a \emph{sheaf} if in addition
\item (Uniqueness) Let $U$ be an open subset of $X$, $s\in\mathcal{F}$, $\{U_i\}_i$ a covering of $U$ by open subsets $U_i$. If $\restr{s}{U_i}=0$ for every $i$, then $s=0$.
\item (Glueing local sections) Let us keep the notation of (d). Let $s_i\in\mathcal{F}(U_i),i\in I$, be sections such that $\restr{s_i}{{U_i\cap U_j}}=\restr{s_j}{U_i\cap U_j}$. Then there exists a section $s\in \mathcal{F}(U)$ such that $\restr{s}{U_i}=s_i$ (this section $s$ is unique by condition (d)).
\end{enumthm}
\end{defn}
\end{document}

Respuesta1

Puedes utilizar \labely \refcomo con otros elementos numerados. Agregue, por ejemplo, \label{item:unique}en el cuarto elemento y utilícelo \ref{item:unique}en el quinto.

En el siguiente código lo eliminé \restrporque no sé cómo se define.

\documentclass{article}
\usepackage{enumitem,amsthm,amsmath}
\newlist{enumthm}{enumerate}{1}
\setlist[enumthm]{label=(\alph*)}
\newtheorem{thm}{Theorem}[section]
\newtheorem{defn}[thm]{Definition}
\begin{document}

\begin{defn}
Let $X$ be a topological space. A \emph{presheaf} $\mathcal{F}$ (of Abelian groups) on $X$ consists an Abelian group $\mathcal{F}(U)$ for every open subset $U$ of $X$, and a group homomorphism (\emph{restriction map}) $\rho_{UV}:\mathcal{F}(U)\to\mathcal{F}(V)$ for every pair of open subsets $V\subseteq U$ which has the following properties:
\begin{enumthm}
\item $\mathcal{F}(\emptyset )=0$;
\item $\rho_{UU}=\operatorname{Id}$;
\item If we have three open subsets $W\subseteq V\subseteq U$, then $\rho_{UW}=\rho_{VW}\circ\rho_{UV}$.\\
A presheaf is said to be a \emph{sheaf} if in addition
\item (Uniqueness) Let $U$ be an open subset of $X$, $s\in\mathcal{F}$, $\{U_i\}_i$ a covering of $U$ by open subsets $U_i$. If ${s}{U_i}=0$ for every $i$, then $s=0$.
\label{item:unique}
\item (Glueing local sections) Let us keep the notation of \ref{item:unique}. Let $s_i\in\mathcal{F}(U_i),i\in I$, be sections such that ${s_i}{{U_i\cap U_j}}={s_j}{U_i\cap U_j}$. Then there exists a section $s\in \mathcal{F}(U)$ such that ${s}{U_i}=s_i$ (this section $s$ is unique by condition \ref{item:unique}).
\end{enumthm}
\end{defn}

\end{document}

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