# Arbital Markdown

The Arbital editor uses Markdown syntax for editing the pages. If you’ve used Reddit or any of the StackOverflow, it’s the same syntax. Here is a helpful intro to Markdown syntax.

## Arbital Markdown syntax

Arbital adds a few extra features to Markdown syntax.

 creates a table of contents, like the one above.

You can quickly link to a page by using id or, even better, alias syntax. For example:
Arbital MarkdownArbital Markdown
Arbital markdownArbital Markdown

If you want the inserted title to be lower-cased, add a dash:
value alignment problemValue alignment problem
value alignment problemvalue alignment problem

If you want to specify what text shows up as the link, use text. For example:
Custom linkCustom link

If you link to a page that doesn’t exist, the link will show up red:
Doesn’t existDoesn’t exist

If you want to just create a red link with some text:
create a page for this concept latercreate a page for this concept later

If you want to mention someone use @userId or @userAlias:
@1@1
@AlexeiAndreev@1
NOTE: the user will get an update if the mention is in a comment. <div><div>

### Summaries

You can set the page’s summary, which shows up in greenlink popovers and other places. For example:
Summary of the page goes here. *Markdown* is okay!
Or to set a specific summary:
Very technical summary. *Markdown* is okay!
Make sure that the entire summary block is in a paragraph of its own.

### Hidden text

You can create hidden text:

Button text
Hidden text goes here.



Surprise!

You can use this for hiding problem answers and asking the user to solve the problem themselves before clicking the button to see the correct answer. Button text is required.

### Notes

You can create notes, which are snippets of text hidden behind a question mark. You can put footnotes or other text that might be interesting to some users, but not to everyone. For example:
noteFun note text! will show up as: noteFun note text!

comment: Alexei Andreev: this is not something we want to advertise at this time.
You can embed votes from other pages. For example:
3r creates this voting bar:
3r

You can leave todo markers for yourself or other authors. For example:
finish this section finish this section

todo: You can put any funky *markdown* syntax here including links. 

This will only appear in the top quality bar when expanded, not the page text. Red links and “todo” markers count towards the todo score, which you will see next to the pages on the Explore and your Profile pages.
todo: You can put any funky markdown syntax here including links.

Similarly, you can leave comments or fixmes for other authors, but without increasing the todo count. For example:
there has got to be a better metaphor for this this needs to be fixed, but I've got it there has got to be a better metaphor for this this needs to be fixed, but I’ve got it

comment: You can put any funky *markdown* syntax here. You can vary the number of %s to envelop other similar blocks. 

Again, this doesn’t show up for the reader in any way.

comment: You can put any funky markdown syntax here. You can vary the number of %s to envelop other similar blocks.

questions and path generation

conditional text

## LaTeX

If you’re new to LaTeX you may want to read the Wikibooks guide

You can use $to create inline mathematical expressions, e.g.$ax^2 + bx + c = 0$ will be displayed as: $$ax^2 + bx + c = 0$$ And $$to create centered math expressions, e.g.$$\lim_{N \to \infty} \sum_{k=1}^N f(t_k) \Delta t$$ will be displayed as: $$\lim_{N \to \infty} \sum_{k=1}^N f(t_k) \Delta t$$$

The editor can get a little slow if you are editing very LaTeX-heavy pages. If this is an issue for you, let us know, and in the meantime you can disable MathJax on the settings page.

Children:

Parents:

• @131, these are all the Arbital-specific markdown addons we have.

• Is “coment” (below) a typo?

“there has got to be a better metaphor for this %%coment: this supports line breaks, but needs to be its own paragraph. You can vary the number of |s to envelop other similar blocks. ”

• Fixed, thanks!

• What’s with the %% marks? Can all [square bracket thingies] be turned into percent-demarcated blocks? How do the percent-demarcated blocks work?

• It’s a totally made up, arbitrary syntax that makes no sense and NEEDS TO GO.

• I mean, I wasn’t going to say it myself, but that was my general impression :-p

(I’m also dubious on the single square bracket, though it seems to be working fine at the moment.)

• “$ax2+bx+c=0$ will be displayed as: $$ax2+bx+c=0$$

“S ax^2 + bx + c = 0 S will be displayed as: $$ax2+bx+c=0$$

(Where S = dollar sign, putting commenting syntax ironically duplicates the error.)

The same problem applies to the centered version.

Now, for some reason the editor displays it just fine, but the actual page does not. (At least on my screen.) The same thing occurs with the previewing of comments versus actually publishing the comments.

“Smart links You can quickly link to a page by using ‘id’ or, even better, ‘alias’ syntax. For example:

Arbital MarkdownArbital Markdown
Arbital MarkdownArbital Markdown

Is 3w both the alias and the id?

• Thanks for bringing this up. The \$ issue is relatively new, since we’ve been changing the editor a lot recently. The Arbital Markdown issue is old, and I’ve never got around to it.

But both are fixed now! :)

• There appears to be an inconsistency in the rendering of this page and its rendering in the preview pane when editing this page. The LaTeX extension behaves differently, so on this page we see only the rendered expressions twice, when what we are meant to see is the markdown and then the rendered version of the equation. But if you go to edit page, in the preview pane it is correct. Is there a way to file a bug?

• Thanks for bringing this up. I fixed the core part of the issue: you can now use backticks to escape LaTeX rendering. However, if you use bold, the behavior is still inconsistent between the editor and live view. We’ll fix that in due time.

Usually commenting on the page is fine for reporting issues, but there is also a “Leave feedback about Arbital” button under the quick menu in the bottom right corner.

• Is there a way to link to a section within a page? (E.g. for tables of contents.)

We do support LaTeX. I think it’s not rendering correctly on Primer on Infinite Series because of <td> and other such tags.