The Stacks project

Work out Brian's suggestion properties diagonals

Thanks to Brian Conrad
http://stacks.math.columbia.edu/tag/0AIP#comment-1944

If you can prove a property P for the maps

U \times_X V ---> U \times V

and P is preserved by base change, then P follows for
the diagonal X ---> X \times X. Applying this to
formal algebraic spaces we get a shorter proof of the
basic properties of their diagonals

LaTeX: \Ob

	Introduced a macro

	\def\Ob{\mathop{\rm Ob}\nolimits}

	and replaced any occurence of \text{Ob}( with \Ob(. There are
	still some occurences of \text{Ob} but these are sets, not the
	operator that takes the set of objects of a category.

LaTeX: \Sch

	Introduced a new macro

	\def\Sch{\textit{Sch}}

	and replaced all the occurences of \textit{Sch} with \Sch.

Started tags infrastructure

	new file:   scripts/add_tags.py
	modified:   scripts/functions.py
	new file:   tags/initial_tags
	new file:   tags/tags

Copied over the stuff on Zariski sites to etale and fppf cases

	modified:   categories.tex
	modified:   fpqc-descent.tex
	modified:   spaces.tex
	modified:   topologies.tex