The Stacks project

covering -> open covering

Thanks to Haohao Liu'
https://stacks.math.columbia.edu/tag/01EP#comment-8265

LaTeX: \Ob

	Introduced a macro

	\def\Ob{\mathop{\rm Ob}\nolimits}

	and replaced any occurence of \text{Ob}( with \Ob(. There are
	still some occurences of \text{Ob} but these are sets, not the
	operator that takes the set of objects of a category.

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.

Started tags infrastructure

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

Slightly more about cohomology

	modified:   cohomology.tex
	modified:   homology.tex
	modified:   injectives.tex
	modified:   sheaves.tex

Tiny bit more on Cech cohomology
Usual problem of not being able to find a suitable reference for
comparing alternating to Cech maps

	modified:   cohomology.tex