The Stacks project

Try to clarify examples in spaces

Thanks to Jiayu Zhao
http://stacks.math.columbia.edu/tag/02Z0#comment-2476

LaTeX: \Spec

	Introduced the macro

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

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

Big set of changes

	Most of this is geared towards proving (in the "correct" way)
	that an algebraic stack is a gerbe if and only if the inertia is
	flat and locally of finite presentation over it.

	Other additions are:
		stackification and inertia
		[U/G] ---> U/G in the case of free actions
		residual gerbes are gerbes (not nec over a point!)
		presentations of inertia stacks
		definition free action
		U ---> U/R is flat + lfp in final bootstrap theorem

Added new tags to the project

	modified:   tags/tags

Some examples of algebraic spaces

	modified:   my.bib
	modified:   spaces.tex