Formatting guide
Posts are written in Markdown with LaTeX mathematics. The editor shows a live preview as you type.
Mathematics
| You write | You get |
|---|---|
$\zeta(s) = \sum_{n\ge 1} n^{-s}$ | \zeta(s) = \sum_{n\ge 1} n^{-s} |
$$\int_0^1 x^n\,dx = \frac{1}{n+1}$$ | \int_0^1 x^n\,dx = \frac{1}{n+1} |
\( a \) and \[ b \] | inline and display math |
\begin{align*}
f(x) &= (x+1)^2 \\
&= x^2 + 2x + 1
\end{align*} | \begin{align*} f(x) &= (x+1)^2 \\ &= x^2 + 2x + 1 \end{align*} |
Math is typeset with KaTeX, which supports most of amsmath, including align, gather, cases, pmatrix and commutative diagrams with CD. Shortcuts \R \C \Q \Z \N \F give blackboard bold letters. Write a literal dollar sign as \$.
Theorems and proofs
\begin{theorem}[Fermat]
There are no positive integers $a,b,c$ with $a^n+b^n=c^n$ for $n>2$.
\end{theorem}
\begin{proof}
See \cite{Wiles95}.
\end{proof}
Available environments: theorem, lemma, proposition, corollary, conjecture, definition, remark, example, question, problem, claim, notation, proof.
Citations
Cite with \cite{key}, optionally with a note: \cite[Thm. 2.1]{key}. Several keys may be separated by commas. A numbered reference list is added to the end of your post.
- arXiv:
\cite{arXiv:2501.01234}or just\cite{2501.01234}— metadata is fetched automatically. - DOI:
\cite{doi:10.4007/annals.2015.181.2.4}— fetched from Crossref. - BibTeX: use the Cite button and paste an entry; then cite it by its key.
- openai/math manuscripts:
\cite{OAI:…}using the key shown on the imported thread.
Every thread has a BibTeX link that exports all references cited on the page.
PDFs and images
Drag files into the editor, paste them, or use Attach. PDFs (up to 50 MB) appear in the post's PDF list and can be read inline. PNG, JPEG, GIF and WebP images are embedded.
Markdown
*italic*, **bold** | italic, bold |
[link](https://arxiv.org) | link |
# Heading, ## Subheading | headings |
- item / 1. item | lists |
> quote | block quote |
`code` and fenced ```lean blocks | code (math is not processed inside code) |
| a | b | tables, footnotes [^1] | GitHub-flavoured extensions |