Hypertext Help with LaTeX

Greek letters

These commands may be used only in math mode. The best way to ensure this in Latex2 $\epsilon$ is to use \ensuremath{}. \ensuremath may be used both in text- and in math-mode, and allows defining a composite symbol once and use it both in text- and in math-mode without having to worry that, say, a sub- or superscript will break the local environment (e.g. if we want to define a symbol e^{\alpha}, then we may define it as \newcommand{\epow}{\ensuremath{e^{\alpha}}} and then use \epow regardless whether it is as a part of an equation (between $ $ in math mode) or whether it is used in the text.