The Stacks project

Swap indices in spectral sequence

Explain how to get spectral sequences Ext

Thanks to Weixia Lu
https://stacks.math.columbia.edu/tag/0AVG#comment-4834

Add a condition to list equivalent ones

Thanks to Noah Olander
https://stacks.math.columbia.edu/tag/091P#comment-3060

More consistent notation for RHom_A(-, -)

Of course in the end it is hopeless to have good notation...

New macro: \Ext

Equivelence beteen torsion and derived complete modules

Wonderful!

Thanks to Bhargav Bhatt for pointing out that this is helpful for the
formulation of Grothendieck's duality statement in local cohomology
(coming up soon).

Many people use the torsion picture to think about derived complete
objects (for example in work of Dan Halperin-Leistner and Antoly
Preygel) and they know this is the same thing as the correspondence is
in Jacob Lurie's work somewhere. Another reference is

Dwyer, W. G. and Greenlees, J. P. C.
Complete modules and torsion modules

which appears to treat a more general question.

Tags: Added new tags

\text{Hom} ---> \Hom

Initial material on derived completion over rings

Todo: How does this compare with the "obvious" definition
that the map

M ---> \lim (M \otimes_A^L A/I^n)

be an isomorphism.