PDF files available

These pdf files are the most up-to-date version of the matter of this site. A pdf file of the complete site is quite large, so I have broken it up into four parts:

Other miscellaneous stuff, overview, some of it rather math-heavy:

And on quite another subject (why not?)

Creative Commons License
"L'univers et moi/The universe and I" by John O'Neall is licensed under a Creative Commons Attribution 4.0 International License.