I'm trying to use symbols such as \lambda
and \delta
but for some reason it's not compiling. I've reproduced the problem in the following code:
\documentclass[12pt,a4paper,oneside]{article}
\begin{document}
\begin{center}
M = < X,Y,S,ta, \delta int, \delta ext, \lambda >
\end{center}
\end{document}
I'm getting the following errors:
Missing $ inserted M = < X,Y,S,ta, \delta
Missing $ inserted I've inserted a beginmath/endmath symbol since I think
Missing } inserted I've inserted something that you may have forgotten.
Extra }, or forgotten \endgroup
Despite these errors, I can still view it in a PDF and it looks like the following:
So, just to clarify what I actually want:

To compile without the errors i.e. how do you make use of symbols like
\delta
etc? 
How do I actually make it display like the following :

As depicted above, I want
int
andext
to be subscripts to the\delta
symbols
Best Answer
You want a centered formula; so the correct way to do it is
This is covered in any basic LaTeX manual, for example The not so short introduction to LaTeX