Help with leaving comments

I have moved my comments policy, with help entering equations to its own page, accessible from the top bar above.

Recently, a few people have had trouble leaving comments on the site, due to incorrectly formatting equations, and some capricious comment mulilation by the WordPress software.  It took me a little while to figure out the exact rules since apparently the comment box which you would enter text into, has slighly different rules than the ones I enter text into as a logged-in user.

So here's the deal.  WordPress uses < and > to enclose html tags.  For example, if you write "<b>this is bold</b>" in a comment, you'll see "this is bold".  Unfortunately, this means that if you include an < followed by an > in your comment, WordPress will interpret whatever is in between as an html tag, and—even if it is not a valid html tag—will simply delete everything in between them!  Even I will be unable to see what you originally wrote.  So do NOT use > or < to mean greater than or less than (unless you use just one kind, or only >'s followed by <'s... but the safest rule is just to avoid them entirely...).

If you want to include greater than or less than symbols, you can write them as {\mathrm \$\$\verb|\|\mathrm{gt}\$\$} or {\mathrm \$\$\verb|\|\mathrm{lt}\$\$}.  That will look like > or < respectively.  Or better still, put your entire equation inside of the double dollar signs using LaTeX notation.

[quietfanatic points out in a comment below that you can also use the html escapes \&gt; or \&lt; if you don't want to use the double dollar signs.]

Also, do NOT try to use wordpress.com latex notation (which has a single dollar signs, and the magic word "latex").  It won't work!  There is a difference between wordpress.com and wordpress.org.  The former is a website used to host WordPress blogs, while the latter is where you download software to host your own WordPress blog.  This is a WordPress.org blog which is hosted on my family server, wall.org.

In order to put LaTeX in a wordpress.org blog, you have to install a special plugin to do so.  You might think that this plugin would use the same notation as wordpress.com, but no it doesn't.  Instead you type \$\$\mathrm{E = mc\verb|^|2}\$\$ to get E = mc^2, and type \$\$!\mathrm{E = mc\verb|^|2.}\$\$ to break it out into a separate line like so:

E = mc^2.

  It's best not to put any spaces after the dollar signs in this case, or they'll make a weird indentation in the next line, as shown here.

Got it?  Good.

About Aron Wall

In 2019, I will be studying quantum gravity and black hole thermodynamics as a Lecturer at the University of Cambridge. Before that, I read Great Books at St. John's College (Santa Fe), got my physics Ph.D. from U Maryland, and did my postdocs at UC Santa Barbara, the Institute for Advanced Study in Princeton, and Stanford. The views expressed on this blog are my own, and should not be attributed to any of these fine institutions.
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4 Responses to Help with leaving comments

  1. quietfanatic says:

    Testing the use of HTML escapes &lt; and &gt; to get < and >. x < y > z

  2. Aron Wall says:

    Yes, that would work too. I've put a comment to that effect in the post above.

  3. g says:

    The comment in the post is (at the time of writing) missing the semicolons after the entity names: it needs to be &lt; and &gt;, not just &lt and &gt (note: I have no idea whether the foregoing will come out right; will post a correction of some kind if not).

    [Fixed. Thanks--AW]

  4. g says:

    (It came out right.)

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help-hint.png
My comment policy, including help with leaving LaTeX equations. Place these between double dollar signs, for example: $$\hbar = 1.05 \times 10^{-34} \text{J s}$$. Avoid using > or < since these may be misinterpreted as html tags.