The Stacks project

Fixed the capitalization of the Stacks project

Consistently refer to the Stacks project as "the Stacks project" in the
text.

Final in series nuerotic edits

Mostly invisible changes

Get rid of some superfluous commands in the text

Fix error

	There was a mistake in the proof of the "explicit" Poincare
	lemma. It turns out that the proof still goes through unchanged,
	except that an earlier lemma has to be formulated with slightly
	weaker assumptions.

	To make sure the formulae are correct this time I wrote a
	PARI/gp script checking all the formulae directly.

Explicit Poincare lemma

	How adjoining a variable doesn't change de Rham cohomology
	provided you can "integrate" functions with respect to the
	variable. This is then used in the proof of the lemma showing
	that crystalline cohomology doesn't change (after inverting p)
	when you add a pth root of a function.

Tags: Added new tags

Cohomology of F-crystals

	Why the cohomology is again an F-crystal...