The Stacks project

Invisible changes

Limit the number of different commands used in math mode

Fix coding style

First pass

sites.tex: Prove Lemma \ref{lemma-mono-epi}

The proof of (1) is my own; the proof of (2) is inspred by the use
of Lemma 1.2.4 in http://www.math.jhu.edu/~bds/stacksnotes.pdf . I guess
it might have been better if I had added the actual lemma, but I had
already written (1) when I found it. Well, I guess it's still better
than "Proof. Omitted".

Beginning work on algebraic spaces

	modified:   algebra.tex
	modified:   fpqc-descent.tex
	modified:   groupoids.tex
	modified:   morphisms.tex
	modified:   sites.tex
	modified:   spaces.tex

Started tags infrastructure

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

Points, points, points...

	modified:   sites.tex

Added proof of sheafification.

	modified:   categories.tex
	modified:   sites.tex