GtkMathView

GtkMathView is a GTK widget for rendering MathML documents. It is meant to be a standalone, light-weight component and not a full browser. GTK applications can use the widget as a window for displaying mathematical formulas and doing simple interactions. Among other features, GtkMathView includes support for breaking long mathematical expressions, rendering of stretchy operators, and provides a customizable support for additional fonts. (Source: http://freecode.com/)