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?