The Stacks project

Fix a couple of double word mistakes

fitting ideal ---> Fitting ideal

Thanks to Kiran Kedaya who writes

There appears to a global spelling issue in the Stacks Project: the
phrase "fitting ideal" appears in lowercase in a great many places, but
it should be "Fitting ideal" because "Fitting" is being used as the
surname of one Hans Fitting. (This is similar to confusion about
"Killing forms" in the theory of Lie algebras, which are named after one
Wilhelm Killing.)

LaTeX: \Spec

	Introduced the macro

	\def\Spec{\mathop{\rm Spec}}

	and changed all the occurences of \text{Spec} into \Spec.

Bunch of changes

	(1) Starting to write about thickenings of algebraic spaces
	(2) Change Omega^1_{X/S} to Omega_{X/S}
	(3) Introduced universal homeomorphisms for algebraic spaces
	(4) If X ---> Y is a surjective, integral morphism of schemes
	and X is an affine scheme, then Y is an affine scheme
	(4) Topological invariance of the site X_{spaces, etale} of an
	algebraic space X (proof unfinished}

	In order to see that also X_{etale} is a topological invariant
	we (I think) need to prove the following result: If X --> Y is a
	integral, universally injective, surjective morphism of
	algebraic spaces then X is a scheme if and only if Y is a
	scheme. There are two proofs of this result in the literature
	(one by David Rydh and one by Brian Conrad); both reduce the
	result to the Noetherian case by limit arguments. I would
	prefer a more direct argument...

Added new tags for labels added in previous commit

	modified:   tags/tags

More setup for tags system

	modified:   algebra.tex
	modified:   categories.tex
	modified:   exercises.tex
	modified:   flat.tex
	modified:   modules.tex
	modified:   scripts/functions.py
	modified:   scripts/make_book.py
	modified:   scripts/make_index.py
	new file:   scripts/make_tags.py
	modified:   scripts/parse.py
	modified:   tags/tags

More setup for tags system

	modified:   algebra.tex
	modified:   categories.tex
	modified:   exercises.tex
	modified:   flat.tex
	modified:   modules.tex
	modified:   scripts/functions.py
	modified:   scripts/make_book.py
	modified:   scripts/make_index.py
	new file:   scripts/make_tags.py
	modified:   scripts/parse.py
	modified:   tags/tags

More neurotic changes

Small clean up of exercises

	modified:   exercises.tex

Fixed up exercises file a bit

	modified:   exercises.tex