I use the even theme.
$$
L=\sum_{(u,v)\in D} \log {\exp(-d(u,v))}
$$
and
$$
-\log {\sum_{v' \in N(u)} \exp(-d(u,v'))}
$$
works but when I combine the two,
$$
L=\sum_{(u,v)\in D} \log {\exp(-d(u,v))}-\log {\sum_{v' \in N(u)} \exp(-d(u,v'))}
$$
It is not outputted as latex. Debugging this thing is also time consuming.
Many markdown processors use the underscore (_) to indicate italics (one at the beginning and one at the end of the text to be italicized). So when your math contains two underscores, Markdown removes them and inserts <em>...</em> tags (or something equivalent to that) before sending the page to the browser. MathJax doesn't process math that contains HTML tags, so the resulting (modified) math is not typeset.
The usual solution is to use a backslash to prevent the underscore from being processed by Markdown, so use \_ in place of _ in your math. You may also need to double some backslashes (e.g., \\ may need to be entered as \\\\ in a Markdown document).
See the MathJax documentation on LaTeX in HTML documents for more details (look for the paragraphs on Markdown).
Related
How do I make org mode not interpret a line that begins with an asterisk as a headline? I have some verbatim text in my org mode document. Some of the lines begin with an asterisk. Org mode interprets these lines as headlines. I don't want that.
Here is the text with some context:
* 20160721 Headline for July 21, 2016
I created a git repository for rfc-tools. It's in
~/Documents/rfc-tools.
Renamed grep-rfc-index.sh to search-rfc-index.sh because it searches.
That it uses grep is irrelevant.
Wrote a README.md for the project. Here it is:
#+BEGIN_SRC text
----- BEGIN QUOTED TEXT -----
This is the README.md for rfc-tools, a collection of programs for
processing IETF RFCs.
* fetch-rfcs-by-title.sh downloads into the current directory the RFCs
whose titles contain the string given on the command line. Uses an
rfc-index file in the current directory. Prefers the PDF version of
RFCs but will obtain the text version if the PDF is not available.
* fetch-sip-rfcs.sh downloads RFCs that contain "Session Initiation"
in their titles into the current directory.
* search-rfc-index.sh searches an rfc-index file in the current
directory for the string given on the command line. The string can
contain spaces.
* join-titles.awk turns the contents of an rfc-index file into a
series of long lines. Each line begins with the RFC number, then a
space, then the rest of the entry from the rfc-index.
----- END QUOTED TEXT -----
#+END_SRC
I want the lines between "----- BEGIN QUOTED TEXT -----" and "----- END QUOTED TEXT -----" to be plain text and subordinate to the headline "20160721 Headline for July 21, 2016". Org mode interprets all lines that begin with an asterisk as top-level headlines.
By the way, the verbatim text is Markdown. I hope that doesn't matter.
worked for me:
#+BEGIN_SRC markdown
Try wrapping your text in one of the various special block tags. For example you could try putting your text inside these tags:
#+BEGIN_SRC text
...
#+END_SRC
Here is a screenshot of how the formatting turns out on my Emacs:
If that doesn't meet your needs, you could try:
#+BEGIN_EXAMPLE
...
#+END_EXAMPLE
Which will render everything inside the tags without markup and in a monospace font.
If that doesn't work either, you could try one of the other kinds of tags listed here.
Escape the * with a comma like this,*
Probably if you type C-c ' to enter a special edit and then exit, org will do that for you.
I think the answer is "You can't do that". I found a way to work around the problem using drawers. The org-mode manual explains that a drawer is a place to put text that you don't want to see all of the time.
A StackExchange user had a question about
getting a custom org drawer to open/close. It seems that for older versions of org-mode, you must tell org-mode the names of your drawers. E.g. If you have a drawer named "COMMANDS"
:COMMANDS:
ls
cat
grep
:END:
you must tell org-mode the name of the drawer using the +DRAWERS keyword:
#+DRAWERS COMMAND
and restart org-mode.
I found a solution:
Escape Character
You may sometimes want to write text that looks like Org syntax, but should really read as plain text. Org may use a specific escape character in some situations, i.e., a backslash in macros (see Macro Replacement) and links (see Link Format), or a comma in source and example blocks (see Literal Examples). In the general case, however, we suggest to use the zero width space. You can insert one with any of the following:
C-x 8 zero width space
C-x 8 200B
For example, in order to write ‘[[1,2]]’ as-is in your document, you may write instead
[X[1,2]]
where ‘X’ denotes the zero width space character.
How to remove zero width space:
sed -i "s/$(echo -ne '\u200b')//g" abc.txt
The <sup></sup> tag is used for superscripts. Creating a code block is done with backticks. The issue I have is when I try to create a superscript within a code block, it prints out the <sup></sup> tag instead of formatting the text between the tag.
How do I have superscript text formatted correctly when it's between backticks?
Post solution edit
Desired output:
A2 instead of A<sup>2</sup>
This is not possible unless you use raw HTML.
The rules specifically state:
With a code span, ampersands and angle brackets are encoded as HTML entities automatically, which makes it easy to include example HTML tags.
In other words, it is not possible to use HTML to format text in a code span. In fact, a code span is plain, unformatted text. Having any of that text appear as a superscript would mean it is not plain, unformatted text. Thus, this is not possible by design.
However, the rules also state:
Markdown is not a replacement for HTML, or even close to it. Its
syntax is very small, corresponding only to a very small subset of
HTML tags. The idea is not to create a syntax that makes it easier
to insert HTML tags. In my opinion, HTML tags are already easy to
insert. The idea for Markdown is to make it easy to read, write, and
edit prose. HTML is a publishing format; Markdown is a writing
format. Thus, Markdown's formatting syntax only addresses issues that
can be conveyed in plain text.
For any markup that is not covered by Markdown's syntax, you simply
use HTML itself. ...
So, if you really need some text in a code span to be in superscript, then use raw HTML for the entire span (be sure to escape things manually as required):
<code>A code span with <sup>superscript</sup> text and escaped characters: "<&>".</code>
Which renders as:
A code span with superscript text and escaped characters: "<&>".
This is expected behaviour:
Markdown wraps a code block in both <pre> and <code> tags.
You can use Unicode superscript and subscript characters within code blocks:
class SomeClass¹ {
}
Inputting these characters will depend on your operating system and configuration. I like to use compose key sequences on my Linux machines. As a last resort you should be able to copy and paste them from something like the Wikipedia page mentioned above.
¹Some interesting footnote, e.g. referencing MDN on <pre> and <code> tags.
If you're luck, the characters you want to superscript (or subscript) may have dedicated codepoints in Unicode. These will work inside codeblocks, as demonstrated in your question, where you include A² in backticks. Eg:
Water (chemical formula H₂O) is transparent, tasteless and odourless.
I've listed out the super and subscript Unicode characters in this Gist. You should be able to copy and paste any you need from there.
I have a large number of Scottish and Welsh accented place names (combining grave, acute, circumflex and diareses) which I need to update to their unicode normalized form, eg, the shorter form 00E1 (\xe1) for á instead of 0061 + 0301 (\x61\x301)
I have found a solution from an old Postgres nabble mail list from 2009, using pl/python,
create or replace function unicode_normalize(str text) returns text as $$
import unicodedata
return unicodedata.normalize('NFC', str.decode('UTF-8'))
$$ LANGUAGE PLPYTHONU;
This works, as expected, but made me wonder if there was any way of doing it directly with built-in Postgres functions. I tried various conversions using convert_to, all in vain.
EDIT: As Craig has pointed out, and one of the things I tried:
SELECT convert_to(E'\u00E1', 'iso-8859-1');
returns \xe1, whereas
SELECT convert_to(E'\u0061\u0301', 'iso-8859-1');
fails with the ERROR: character 0xcc81 of encoding "UTF8" has no equivalent in "LATIN1"
I think this is a Pg bug.
In my opinion, PostgreSQL should be normalizing utf-8 into pre-composed form before performing encoding conversions. The result of the conversions shown are wrong.
I'll raise it on pgsql-bugs ... done.
http://www.postgresql.org/message-id/53E179E1.3060404#2ndquadrant.com
You should be able to follow the thread there.
Edit: pgsql-hackers doesn't appear to agree, so this is unlikely to change in a hurry. I strongly advise you to normalise your UTF-8 at your application input boundaries.
BTW, this can be simplified down to:
regress=> SELECT 'á' = 'á';
?column?
----------
f
(1 row)
which is plain crazy-talk, but is permitted. The first is precomposed, the second is not. (To see this result you'll have to copy & paste, and it'll only work if your browser or terminal don't normalize utf-8).
If you're using Firefox you might not see the above correctly; Chrome renders it correctly. Here's what you should see if your browser handles decomposed Unicode correctly:
PostgreSQL 13 has introduced string function normalize ( text [, form ] ) → text, which is available when the server encoding is UTF8.
> select 'päivää' = 'päivää' as without, normalize('päivää') = normalize('päivää') as with_norm ;
without | with_norm
---------+-----------
f | t
(1 row)
Note that I am expecting this to miss any indices, and therefore using this blindly in a hot production query is prone to be a recipe for disaster.
Great news for us who have naively stored NFD filenames from Mac users in our databases.
I am currently using the TEX filter to write some digital logic expressions in Moodle and am running in to a significant issue.
If I write $$ \overline{A}\overline{B}\overline{C} $$, the filter displays the overlines as a single overline instead of three separate overlines. Inserting individual spaces does not seem to work either.
It doesn't seem to be a typeface issue; I changed to a bold math typeface and the same issue appears.
Is there a way to insert a hard space between characters in TEX math? Or a way to split the overlines?
Thanks!
#MLAU Fractions in TeX are actually simple, as long as you remember the rules.
$$ \frac{numerator}{denominator} $$ which produces
Following this lead, I tried this in a Github README.md:
<span style="vertical-align: baseline; position: relative;top: -0.5em;>text in superscript</span>
Does not work, the text appears as normal. Help?
Use the <sup></sup>tag (<sub></sub> is the equivalent for subscripts). See this gist for an example.
You have a few options for this. The answer depends on exactly what you're trying to do, how readable you want the content to be when viewed as Markdown and where your content will be rendered:
HTML Tags
As others have said, <sup> and <sub> tags work well for arbitrary text. Embedding HTML in a Markdown document like this is well supported so this approach should work with most tools that render Markdown.
Personally, I find HTML impairs the readable of Markdown somewhat, when working with it "bare" (eg. in a text editor) but small tags like this aren't too bad.
LaTeX (New!)
As of May 2022, GitHub supports embedding LaTeX expressions in Markdown docs directly. This gives us new way to render arbitrary text as superscript or subscript in GitHub flavoured Markdown, and it works quite well.
LaTeX expressions are delineated by $$ for blocks or $ for inline expressions. In LaTeX you indicate superscript with the ^ and subscript with _. Curly braces ({ and }) can be used to group characters. You also need to escape spaces with a backslash. The GitHub implementation uses MathJax so see their docs for what else is possible.
You can use super or subscript for mathematical expressions that require it, eg:
$$e^{-\frac{t}{RC}}$$
Which renders as..
Or render arbitrary text as super or subscript inline, eg:
And so it was indeed: she was now only $_{ten\ inches\ high}$, and her face brightened up at the thought that she was now the right size for going through the little door into that lovely garden.
Which renders as..
I've put a few other examples here in a Gist.
Unicode
If the superscript (or subscript) you need is of a mathematical nature, Unicode may well have you covered.
I've compiled a list of all the Unicode super and subscript characters I could identify in this gist. Some of the more common/useful ones are:
⁰ SUPERSCRIPT ZERO (U+2070)
¹ SUPERSCRIPT ONE (U+00B9)
² SUPERSCRIPT TWO (U+00B2)
³ SUPERSCRIPT THREE (U+00B3)
ⁿ SUPERSCRIPT LATIN SMALL LETTER N (U+207F)
People also often reach for <sup> and <sub> tags in an attempt to render specific symbols like these:
™ TRADE MARK SIGN (U+2122)
® REGISTERED SIGN (U+00AE)
℠ SERVICE MARK (U+2120)
Assuming your editor supports Unicode, you can copy and paste the characters above directly into your document or find them in your systems emoji and symbols picker.
On MacOS, simultaneously press the Command ⌘ + Control + Space keys to open the emoji picker. You can browse or search, or click the small icon in the top right to open the more advanced Character Viewer.
On Windows, you can a emoji and symbol picker by pressing ⊞ Windows + ..
Alternatively, if you're putting these characters in an HTML document, you could use the hex values above in an HTML character escape. Eg, ² instead of ². This works with GitHub (and should work anywhere else your Markdown is rendered to HTML) but is less readable when presented as raw text.
Images
If your requirements are especially unusual, you can always just inline an image. The GitHub supported syntax is:
You can use a full path (eg. starting with https:// or http://) but it's often easier to use a relative path, which will load the image from the repo, relative to the Markdown document.
If you happen to know LaTeX (or want to learn it) you could do just about any text manipulation imaginable and render it to an image. Sites like Quicklatex make this quite easy. Of course, if you know your document will be rendered on GitHub, you can use the new (2022) embedded LaTeX syntax discussed earlier)
Comments about previous answers
The universal solution is using the HTML tag <sup>, as suggested in the main answer.
However, the idea behind Markdown is precisely to avoid the use of such tags:
The document should look nice as plain text, not only when rendered.
Another answer proposes using Unicode characters, which makes the document look nice as a plain text document but could reduce compatibility.
Finally, I would like to remember the simplest solution for some documents: the character ^.
Some Markdown implementation (e.g. MacDown in macOS) interprets the caret as an instruction for superscript.
Ex.
Sin^2 + Cos^2 = 1
Clearly, Stack Overflow does not interpret the caret as a superscript instruction. However, the text is comprehensible, and this is what really matters when using Markdown.
If you only need superscript numbers, you can use pure Unicode. It provides all numbers plus several additional characters as superscripts:
x⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾ⁿⁱ
However, it might be that the chosen font does not support them, so be sure to check the rendered output.
In fact, there are even quite a few superscript letters, however, their intended use might not be for superscript, and font support might be even worse. Use your own judgement.