# Math Help - pmatrix error

1. ## pmatrix error

In this thread, I couldn't get the following to work.

\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix}=\begi n{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}

It gives
$\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix}=\begi n{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}$

I had to interject "[/tex]$$" after "=". Why is that? PS: I have no idea where the space in the second "begin" comes from. It's not there when I edit the text. 2. ## Re: pmatrix error I also noticed that spaces are sometimes inserted into LaTeX commands, which makes them invalid. 3. ## Re: pmatrix error Originally Posted by ymar In this thread, I couldn't get the following to work. \begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix}=\begi n{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix} It gives $\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix}=\begi n{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}$ I had to interject "$$$$" after "=". Why is that? PS: I have no idea where the space in the second "begin" comes from. It's not there when I edit the text. Seperating LaTeX special characters with spaces gives: $\begin{pmatrix}x_1 \\ \vdots \\ x_n \end{pmatrix} = \begin{pmatrix}\alpha \wedge x_1 \\ \vdots \\ \alpha \wedge x_n \end{pmatrix}$ [tex]\begin{pmatrix}x_1 \\ \vdots \\ x_n \end{pmatrix} = \begin{pmatrix}\alpha \wedge x_1 \\ \vdots \\ \alpha \wedge x_n \end{pmatrix}$$

$$\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix}=\begi n{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}$$

(the space in the second begin is not really there, I don't know why it renders that way)

Obviously somewhere in there the interpreter is having difficulty in determining where one thing ends and the next starts - possibly causing a buffer overflow. Also though not all the spaces I have put in are essential to getting this to render, putting in spaces make the LaTeX more readable.

The problem could also be due to vBulletin putting in an extra space when it needs to stop for breath in a long string without spaces. Which seems to be the case, as demonstrated with the following example with just one space inserted before the second \begin:

$$\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix} =\begin{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}$$

$\begin{pmatrix}x_1\\\vdots\\x_n\end{pmatrix} =\begin{pmatrix}\alpha\wedge x_1\\\vdots\\\alpha\wedge x_n\end{pmatrix}$

CB

4. ## Re: pmatrix error

i have noticed that with vmatrix, bmatrix and pmatrix commands the \begin and \end parts often need an extra space in front to parse correctly (the delimiters often fail to display if i don't do this).

also, "new row" commands within these commands (the \\ at the end of every row) often need an extra space, especially if you are using something like \greekletter as the first character of a subsequent row (i think this confuses the interpreter).