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 Yearling
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Feb
11
revised How would you go about proving that any complex line is a curve on the Riemann sphere?
Removed Riemannian geometry tag
Jan
18
asked Semisimplicity of Frobenius action on H^1(X,Q_p)
Jan
5
awarded  Yearling
Nov
30
comment Compositum of all Galois extensions of prime power degree
It's an isomorphism.
Nov
29
comment Compositum of all Galois extensions of prime power degree
@AngeloRendina By $E_i$, do you mean what I called $K_i$? If so, automorphisms of the $E_i$ are not subgroups but quotient groups. So it should be correct as I originally wrote it.
Nov
27
revised Compositum of all Galois extensions of prime power degree
added 17 characters in body
Nov
27
revised Compositum of all Galois extensions of prime power degree
added 664 characters in body
Nov
27
comment Compositum of all Galois extensions of prime power degree
Yes, there's some work to be done here, but the fact that the subextensions are Galois means it will work out. Give me a few minutes and I'll sketch out something more complete.
Nov
27
comment Compositum of all Galois extensions of prime power degree
Well, what is the compositum? It's the set of elements that can be obtained from elements of these finite extensions. So you just have to show, by induction, that if you take the compositum of two finite Galois extensions of $p$-power order, the compositum is again of $p$-power order (and so is its Galois closure)
Nov
27
answered Compositum of all Galois extensions of prime power degree
Nov
21
comment Prove that any subfield of $\Bbb R$ contains $\Bbb Q$
Your proof is correct, but could perhaps use some more details (why do you reach each conclusion?) Also, why doesn't your proof work for $\mathbb Z/p$? You must be using some property of $\mathbb R$, but you don't explicitly say what property you are using.
Nov
20
revised Fun Lagrange multiplier problem?
edited tags
Nov
17
comment Why every central simple algebra has a splitting field
@Dune The Tensor product of a central simple algebra with a simple algebra is always simple.
Nov
17
revised Why every central simple algebra has a splitting field
edited tags
Nov
9
comment A proposition on Mobius map
The only group-theoretic observation, which we can make without using the language of groups, is that given an automorphism $\psi$ with $\psi(a)=0$ for some $a$, we can write $\psi=\tau \circ \varphi_a$, where $\tau$ maps $0$ to $0$.
Nov
8
answered A proposition on Mobius map
Oct
21
revised product considering the period of index over a cyclotomic extension
added 31 characters in body; edited title
Oct
7
awarded  Nice Answer
Sep
30
reviewed Looks OK Thinking about a probability problem in terms of sets.
Sep
30
awarded  Explainer