How could I stack two symbols on top of each other, so that they would appear smaller, i.e. something like \begin{array}a\\b\end{array}, but would fit nicely in a single line with the rest? So for example, I want to write blah blah blah $S(\begin{array}a\\b\end{array})$ blah blah in one single line.
Thanks a lot!

amsmathhas thesmallmatrixenvironment for this. – egreg Jul 10 '13 at 13:42smallmatrixworked perfectly! Thanks pal! =) @StevenB.Segletes - Thanks, I will wait for this! So far the small matrix suits my taste, but I am eager to also learn another method as you suggested withstackengine. Thanks a lot! =) – Eric Jul 10 '13 at 13:46