The Stacks project

New macro: \Ext

Fix two small things

Thanks to Anfang Zhou
http://stacks.math.columbia.edu/tag/05E2#comment-737
http://stacks.math.columbia.edu/tag/0098#comment-746

'pull back' ----> 'pullback'

	This is a bit more tricky as we sometimes use the pull in 'pull back' as a verb.

'push out' ---> 'pushout'

LaTeX: Hom and SheafHom

	Introduced the macros

	\def\Hom{\mathop{\rm Hom}\nolimits}
	\def\SheafHom{\mathop{\mathcal{H}\!{\it om}}\nolimits}

	and replaced all the occurences of \text{Hom} and \textit{Hom}
	with these.

Tags: Added new tags

Formal glueing

	Bhargav Bhatt submitted a write up on formal glueing that I
	edited to make it fit better with the stacks project. The
	statement implies for example the following: Suppose that C is a
	smooth curve over a field k and p a closed point of C. Then
	vector bundles over C are the same thing as triples (E, E', phi)
	where E is a vector bundle on C - {p}, E' is a vector bundle on
	the formal completion of C at p, and phi is an isomorphism
	between E and E' over the punctured formal completion of C at
	p. This is sometimes a good way to think about vector bundles
	(e.g. because the vectorbundle E is trivial if it has trivial
	determinant).

	Adding this caused me to start a new chapter on algebra called
	"More on Algebra". If you have a less prosaic title, then drop
	me an email.