History of tag 05DM
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changed the proof
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2011-06-15 |
78133d1 |
Fixed references to short titles
using the script we will add in the next commit
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changed the statement and the proof
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2010-12-07 |
0b19c63 |
More examples of pure modules
In particular it turns out that if we have R ---> S and N an
S-module which is countably generated and Mittag-Leffler as an
R-module, then it is pure relative to S/R. This finally puts a
direct link between purity and the Mittag-Leffler condition
which I was looking for.
Note that there is an example that shows that one cannot go the
other way. Namely, there exist pure modules over S/R (even when
everything of finite type and Noetherian) which are not
Mittag-Leffler.
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changed the statement
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2010-12-05 |
85b43fe |
Remove finite type hypothesis
In some sense this is a simplification.
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changed the statement
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2010-11-27 |
47011a9 |
Fix an example
Actually the example was correct but the thing it was a counter
example against was formulated incorrectly. Now we added it as
an actual lemma in more-morphisms.tex
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changed the proof
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2010-10-20 |
7f432aa |
Explain purity
We added the following fun lemma: Suppose R ---> S is a ring map
with R local and M an R-module. Assume that
S/m_RS is Noetherian
M/m_RM is finite over S/m_RS
M is projective as an R-module
Then any prime q of S which is an associated prime of M \otimes
k(p) where p = q \cap R is contained in a prime of S lying over
m_R. This lemma in some sense explains the notion of purity
introduced in Raynaud-Gruson...
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assigned tag 05DM
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2010-10-07 |
84ec8c5
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Tags: Added new tags
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created statement with label lemma-universally-injective-to-completion-flat in flat.tex
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2010-10-06 |
5115011 |
First projectivity result
as stated this lemma can be used to proceed by Noetherian
induction on the base in certain situations.
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