The Stacks project

Work out Brian's suggestion properties diagonals

Thanks to Brian Conrad
http://stacks.math.columbia.edu/tag/0AIP#comment-1944

If you can prove a property P for the maps

U \times_X V ---> U \times V

and P is preserved by base change, then P follows for
the diagonal X ---> X \times X. Applying this to
formal algebraic spaces we get a shorter proof of the
basic properties of their diagonals

Example of David Hansen

Thanks to Brian Conrad for asking for an example and pointing out a typo
http://stacks.math.columbia.edu/tag/0AIT#comment-1946

Spell checking formal-spaces.tex

Tags: Added new tags

Reference to Yasuda

Contrary to what we said in commit
228a61b42f1d482dfafa7a348495b13b0bd7c716
there is a reference for the result proved in that commit. We have added
it in this commit. We also clarified the situation re ideals of
definition and what the statement means for (usual) formal schemes.

Quasi-compact and quasi-separated formal algebraic spaces

It tunrs out these are always colimits; it seems that this was missed in
the literature on formal schemes