improve the preliminary section, and rename to...

"Background".

The filename will be kept (for historical importance? Dunno).

Explained normalization and removed placeholder for Jacobian. Looks good enough.
hammered out the structure of the report

All sections are in the TOC now, with labels.

Improved Introduction (previously Background, still named report-bg.tex)
to include major results and some directly related conjectures. Robin's
part is merely a placeholder for now.