This package consists of prerex.sty, a LaTeX package for
producing charts of course nodes linked by arrows representing
pre- and co-requisites, and prerex, an interactive program for
creating and editing chart descriptions. The implementation of
prerex.sty uses PGF, so that it may be used equally happily
with LaTeX or pdfLaTeX; prerex itself is written in C. The
package includes source code for a previewer application, a
lightweight Qt-4 and poppler-based prerex-enabled PDF viewer.