History of tag 049A
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changed the statement
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2013-05-24 |
719c185 |
LaTeX: \etale
Introduced the macro
\def\etale{{\acute{e}tale}}
and replaced all occurences of \acute{e}tale by \etale
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changed the statement
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2010-10-09 |
2b090dd |
End conversion of etale to \'etale.
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changed the statement
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2010-07-01 |
f396b03 |
The stack of torsors
There are many different possible definitions for the stack of
torsors for a group algebraic space G over a base B. You can
look at principal homogeneous spaces for the fpqc topology, or,
and this is more natural for us, look at fppf G-torsors. One
reason this is natural is that you get the same thing as looking
at G-torsors where you think of G as a sheaf!
If G is a group scheme over a scheme, then you could also just
look at those fppf G-torsors which are representable. Of course
this is somehow completely the wrong thing to do, but on the
other hand it is what comes natural since we know more about
schemes than about algebraic spaces.
We try to discuss all the possible variants extensively in a
section in the chapter "Examples of Stacks". In the future we
will add some lemmas/propositions/theorems saying that if G has
reasonable properties then these stacks all agree.
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changed the statement
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2010-06-02 |
4944f74 |
Lemmas on maps of groupoids on fields
Images of such maps are often again groupoids, etc. Similar to
lemmas on homomorphisms of group schsmes over fields.
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assigned tag 049A
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2010-03-01 |
bc8624b
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More Morphisms Spaces: Finish proof characterization finite presentation
Also add the chapter to the project, some fixes in scripts,
added tags, etc
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created statement with label definition-principal-homogeneous-space in groupoids.tex
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2010-02-27 |
08e7da2 |
Groupoids: Section on torsors
Mainly definitions
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