Cross-references
Give an environment an identifier, and cite it. A reference can come before what it refers to, as 2 does here.
Theorem 1 (Euler). \(e^{i\pi} + 1 = 0\).
Lemma 2. \(e^z \neq 0\) for every complex \(z\).
| You write | You get | LaTeX gets |
|---|---|---|
@euler |
1 | \ref{euler} |
[@euler] |
(1) | \eqref{euler} |
@Euler |
Theorem 1 | Theorem~\ref{euler} |
[@Euler] |
(Theorem 1) | (Theorem~\ref{euler}) |
[@euler; @nz] |
(1), (2) | \eqref{euler}, \eqref{nz} |
\ref{nz} |
2 | \ref{nz} |
\eqref{nz} |
(2) | \eqref{nz} |
Capitalising the first letter of the identifier, @Nz, puts the environment’s name before the number: Lemma 2. It stays right if Lemma later becomes Proposition. For this, use identifiers that start with a lowercase letter.
In the italic body of a theorem, a number from @id or \ref is italic, as in LaTeX, and one from [@id] or \eqref upright:
Source
This page is made from the Markdown below, and LaTeX output gets the LaTeX beside it. The PDF under Other Formats is that LaTeX, typeset by amsthm.
---
title: Cross-references
amsthm:
plain:
- Theorem:
- Lemma
---
Give an environment an identifier, and cite it. A reference can come
before what it refers to, as @nz does here.
::: {#euler .Theorem info="Euler"}
$e^{i\pi} + 1 = 0$.
:::
::: {#nz .Lemma}
$e^z \neq 0$ for every complex $z$.
:::
| You write | You get | LaTeX gets |
| --------------- | --------------- | ---------------------------- |
| `@euler` | @euler | `\ref{euler}` |
| `[@euler]` | [@euler] | `\eqref{euler}` |
| `@Euler` | @Euler | `Theorem~\ref{euler}` |
| `[@Euler]` | [@Euler] | `(Theorem~\ref{euler})` |
| `[@euler; @nz]` | [@euler; @nz] | `\eqref{euler}, \eqref{nz}` |
| `\ref{nz}` | \ref{nz} | `\ref{nz}` |
| `\eqref{nz}` | \eqref{nz} | `\eqref{nz}` |
Capitalising the first letter of the identifier, `@Nz`, puts the
environment's name before the number: @Nz. It stays right if Lemma
later becomes Proposition. For this, use identifiers that start with a
lowercase letter.
In the italic body of a theorem, a number from `@id` or `\ref` is
italic, as in LaTeX, and one from `[@id]` or `\eqref` upright:
::: Theorem
By @Nz and [@euler], the exponential has no zeros.
:::\usepackage{amsthm}
\theoremstyle{plain}
\newtheorem{Theorem}{Theorem}
\newtheorem{Lemma}[Theorem]{Lemma}
Give an environment an identifier, and cite it. A reference can come
before what it refers to, as \ref{nz} does here.
\begin{Theorem}[Euler]\label{euler}
\(e^{i\pi} + 1 = 0\).
\end{Theorem}
\begin{Lemma}\label{nz}
\(e^z \neq 0\) for every complex \(z\).
\end{Lemma}
{\def\LTcaptype{none} % do not increment counter
\begin{longtable}[]{@{}lll@{}}
\toprule\noalign{}
You write & You get & LaTeX gets \\
\midrule\noalign{}
\endhead
\bottomrule\noalign{}
\endlastfoot
\texttt{@euler} & \ref{euler} & \texttt{\textbackslash{}ref\{euler\}} \\
\texttt{{[}@euler{]}} & \eqref{euler} &
\texttt{\textbackslash{}eqref\{euler\}} \\
\texttt{@Euler} & Theorem~\ref{euler} &
\texttt{Theorem\textasciitilde{}\textbackslash{}ref\{euler\}} \\
\texttt{{[}@Euler{]}} & (Theorem~\ref{euler}) &
\texttt{(Theorem\textasciitilde{}\textbackslash{}ref\{euler\})} \\
\texttt{{[}@euler;\ @nz{]}} & \eqref{euler}, \eqref{nz} &
\texttt{\textbackslash{}eqref\{euler\},\ \textbackslash{}eqref\{nz\}} \\
\texttt{\textbackslash{}ref\{nz\}} & \ref{nz} &
\texttt{\textbackslash{}ref\{nz\}} \\
\texttt{\textbackslash{}eqref\{nz\}} & \eqref{nz} &
\texttt{\textbackslash{}eqref\{nz\}} \\
\end{longtable}
}
Capitalising the first letter of the identifier, \texttt{@Nz}, puts the
environment's name before the number: Lemma~\ref{nz}. It stays right if
Lemma later becomes Proposition. For this, use identifiers that start
with a lowercase letter.
In the italic body of a theorem, a number from \texttt{@id} or
\texttt{\textbackslash{}ref} is italic, as in LaTeX, and one from
\texttt{{[}@id{]}} or \texttt{\textbackslash{}eqref} upright:
\begin{Theorem}
By Lemma~\ref{nz} and \eqref{euler}, the exponential has no zeros.
\end{Theorem}