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Bug in Markdown editor with LaTex (array environment does not work)?

+3 votes
1,296 views
asked Oct 24, 2013 in Q2A Core by Dilaton
edited Oct 25, 2013 by Dilaton

After installing the markdown editor with LaTex

https://github.com/thibaultduponchelle/q2a-markdown-editor-latex

writing math worked nicely, until I tried to use the

\begin{array}

\end{array}

environment , for example as in this question:

Looking at $5D$ Kaluza-Klein theory, the Kaluza-Klein metric is given by

$$
g_{mn} = \left(
\begin{array}{cc}
    g_{\mu\nu} & g_{\mu 5} \\
    g_{5\nu} &  g_{55} \\
\end{array}
\right)
$$

where $g_{\mu\nu}$ corresponds to the ordinary four dimensional metric and $g_{\mu 5}$ is the ordinary four dimensional Maxwell gauge field, $g_{55}$ is the dilaton  field.

As there is one dilaton for one extra dimension, I naively would expect that the zero mass states of closed string theory, which can be written as

$$
\sum\limits_{I.J} R_{I.J} a_1^{I\dagger} \bar{a}_1^{I\dagger} ¦p^{+},\vec{p}_T \rangle
$$

and the square matrix $R_{I.J}$ can be separated into a symmetric traceless part corresponding to the graviton field, an antisymmetric part corresponding to a generalized Maxwell gauge field, and the trace which corresponds to the dilaton field.

Why is there only one dilaton field given by the trace of $R_{I.J}$, instead of $22$ dilaton fields corresponding to $22$ extra dimensions of closed string theory which has critical dimension $D = 26$? For example, why are there not $22$ dilaton fields needed to parameterize the shape of the 22 extra dimensions if they are compactified?

Bug:

In the preview, all of the math compiles apart from the fact that the array is displayed as a single column instead of a 2x2 matrix.

When posting the question, all of the maths get scrampled up.

Howver, looking at the edit history by applying this plug-in

http://www.question2answer.org/qa/17583/edit-history-plugin-improvements-bugs

all the maths works including the matrix.

What can be done about this bug?

 

commented Oct 25, 2013 by Dimension10
Is there the same problem with the \begin{bmatrix}\end{bmatrix} or the  \begin{pmatrix}\end{pmatrix} format ?
commented Oct 25, 2013 by Dilaton
That does not work either ... :-/

2 Answers

+1 vote
answered Dec 23, 2014 by thibaultduponchelle
I'm the author of this plugin and it's buggy I know... Sorry for that...

But, I have a good news ;)

Please move to q2a ckeditor latex plugin :  https://github.com/thibaultduponchelle/q2a-ckeditor-latex

This is not a markdown editor but a std wysiwyg ckeditor4 with latex (math preview window) and it should work better.

I made this plugin long time ago (when ckeditor4 was released, at least one year) but never published it.

It needs beta testers, so please report any bug.

Best regards.

Thibault
0 votes
answered Dec 23, 2014 by Fredy Angols

\begin{array}

\end{array}

environment , for example as in this question:

Looking at $5D$ Kaluza-Klein theory, the Kaluza-Klein metric is given by 

$$ 
g_{mn} = \left( 
\begin{array}{cc} 
    g_{\mu\nu} & g_{\mu 5} \\ 
    g_{5\nu} &  g_{55} \\ 
\end{array} 
\right) 
$$ 

...