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seen Oct 21 at 16:21

Oct
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Sep
30
awarded  Explainer
Sep
22
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Jul
2
awarded  Curious
Jun
10
accepted Does the Windows version of MAGMA have a memory limit?
Jun
10
answered Does the Windows version of MAGMA have a memory limit?
Jun
5
comment Exponential and log functions compose to identity
Would you happen to know an argument for the other direction of the composition, $\mathrm{log}\circ\mathrm{exp} = 1$?
Jun
4
comment Matrix logarithms for various algebraic groups
Jared as in Friedlanders student? We talked at the conference last week. Basically I'm trying to show that these groups are "logarithmic type". I just figured out $SO$ using a nasty combinatorial argument. I was really hoping that this was known and there'd be a slick way to do it.
Jun
4
asked Matrix logarithms for various algebraic groups
May
4
comment Exercise 2.11 Atiyah-Macdonald
To start with, do you know what 2.4 gives you?
May
4
answered Exercise 2.11 Atiyah-Macdonald
Apr
30
comment $\langle x \rangle$ is a direct summand of a finite abelian group where $x$ is maximal order
Ha, silly me. I'm not used to finite things. Anyway, in that case your maximal $H$ would be $H = \{e\}$, so if you can show that being maximal implies $\langle x, H\rangle = G$ then you don't need to worry about this case.
Apr
30
comment $\langle x \rangle$ is a direct summand of a finite abelian group where $x$ is maximal order
I haven't checked the details so I'll leave this as a comment and not an answer. But I think you should use Zorn's lemma. Choose $H$ to maximal among subgroups with the property that $H \cap \langle x\rangle = \{e\}$. Then you'll have to show that this maximality property implies $\langle x, H\rangle = G$, maybe by using $y \in G \setminus \langle x, H\rangle$ to construct a larger $H$.
Apr
27
answered isomorphism $\mathrm{Hom}_G(k,V)\to V^G$
Apr
24
answered Localisation isomorphic to a quotient of polynomial ring
Apr
24
comment Does the Windows version of MAGMA have a memory limit?
@mathguy: Apparently there are two MAGMA's, the one I am speaking of is different than the one you've linked to: magma.maths.usyd.edu.au/magma
Apr
24
comment Does the Windows version of MAGMA have a memory limit?
GetMemoryLimit() returns 0 and generally the error messages say that the current session is ~1200MB when failure occurs. So I guess this means it's some sort of system error on the server. But if there's 16GB of memory available I don't know why this would be.
Apr
23
asked Does the Windows version of MAGMA have a memory limit?
Apr
22
comment A homomorphism induces a continuous map from ${\rm Spec}(A') \to {\rm Spec}(A)$.
When $h$ is not surjective. For example if $h\colon k[x] \to k[x, y]$ is the obvious inclusion and $\mathfrak a = (x)$ is the ideal generated by $x$ then $h(\mathfrak a)$ is not closed under multiplication by $y$.
Apr
22
comment A homomorphism induces a continuous map from ${\rm Spec}(A') \to {\rm Spec}(A)$.
You need an ideal in $A'$ whose definition should depend on the ideal $\mathfrak a$. Well... there's really only one way to turn $\mathfrak a$ into an ideal of $A'$ so either that way is gonna work or the theorem probably isn't true.