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Peter Mueller

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Name Peter Mueller
Member for 1 year
Seen 5 hours ago
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Location Würzburg
Age 47
I'm a professor of mathematics at the University of Würzburg (Germany). For further infos see my web page.
Jun
12
awarded  Enlightened
Jun
12
accepted A conjecture in Number Theory
May
17
comment Good effective versions of theorems of Artin and Brauer
If nobody here has an idea or reference, you might ask Robert Boltje (boltje.math.ucsc.edu), he did some work on various aspects of Brauer's induction theorem.
May
15
accepted A generalisation of the theorem of Maschke
May
14
comment Simplifying an algebraic integer expression
@Randall: Isn't your question essentially the same one as your question mathoverflow.net/questions/24513/… from 3 years ago? How are your numbers $pxy$ given, by minimal polynomials or complex floats up to some precision?
May
14
answered A generalisation of the theorem of Maschke
Apr
26
comment Rational functions with a common iterate
@Anixx: Maybe because it is not clear at all what you are suggesting. (I didn't downvote though.) It seems to me that your approach more or less only works if you can compute a closed expression for the higher iterates - which is trivial in your examples - but impossible in general.
Apr
22
comment A question from complex analysis
@bo.gu: I do not understand your question. Are you asking how I did find the counter-examples, or do you want to know why these polynomials yield counter-examples?
Apr
20
accepted A question from complex analysis
Apr
19
revised A question from complex analysis
added 274 characters in body
Apr
19
comment A question from complex analysis
Sorry, I fixed the typo.
Apr
19
revised A question from complex analysis
fixed typo
Apr
19
answered A question from complex analysis
Apr
16
comment Tame morphism from a curve to $\mathbb{P}^1$
@Will: $S^4$ is meant to be the symmetric group on $4$ letters? Anyway, in this characteristic $2$ context without Riemann's existence theorem, it isn't clear to me that this cover exists. I would be more convinced if one would write it down explicitly for an elliptic curve in Weierstrass form.
Apr
7
awarded  Enlightened
Apr
7
accepted Inequality with Euler’s totient function
Apr
4
comment Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
@James D. Taylor: I changed my answer, so your comment probably does not apply anymore.
Apr
4
revised Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
Reformulated the answer, dropped the trivial part.
Apr
3
comment Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
How could it help here? The base fields are ^number fields^. Even over $p$-adic fields, the Krasner lemma only gives a sufficient, but not a necessary criterion for equality of fields.
Apr
3
revised Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
Enhanced answer; added 4 characters in body
Apr
3
revised Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
deleted 196 characters in body
Apr
3
answered Is there a nice criterion for when the splitting fields of two irreducible polynomials are equal?
Apr
3
comment Books on advanced galois theory
Look at the list of books given in en.wikipedia.org/wiki/Inverse_Galois_theory In addition to that, also the book Field Arithmetic by Fried and Jarden contains quite a bit of (infinite) Galois theory. Furthermore, Algebraic Patching by Jarden is mostly about a relatively recent technique in Galois theory.
Apr
1
accepted Simple field extension and rational points
Apr
1
comment Simple field extension and rational points
I extended the answer, hope it is clearer now.
Apr
1
revised Simple field extension and rational points
Extended the argument in view of a comment.
Mar
31
revised Simple field extension and rational points
improved proof, better readability
Mar
31
answered Simple field extension and rational points
Mar
29
comment irreducible polynomials with arithmetic progression coefficients
@Aaron: Of course, there are many obvious examples like this: If $x-x_0$ is to be a factor of $f_{a,b}(x)=\sum_{k=0}^n(a+bk)x^k$, then there is a linear equation for $a,b$ from $f_{a,b}(x_0)=0$.
Mar
29
comment irreducible polynomials with arithmetic progression coefficients
@Greg: My comment does not contribute to the question at all. The question wants $a,b$ fixed and $n$ running, while my comment is about $n$ fixed and $a,b$ varying.
Mar
29
comment irreducible polynomials with arithmetic progression coefficients
@David: I think that Will fixes $n$. And then it is certainly a consequence of Hilbert's irreducibility theorem, since $\sum_{k=0}^n(a+bk)x^k$ is irreducible over $\mathbb Q(a,b)$, for variables $a,b$.
Mar
27
accepted Fixed points of group action
Mar
27
awarded  Nice Answer
Mar
26
revised Fixed points of group action
Adapted answer to the edit of the question; deleted 1 characters in body
Mar
26
answered Fixed points of group action
Mar
18
comment Principal maximal ideals in Z[x]/(F)
$x^4-4x^2+9$ seems to be a promising candidate.
Mar
18
comment Principal maximal ideals in Z[x]/(F)
I think $F=x^4-10x^2+1$ doesn't work either, for $f=x+2$ is a divisor for $F$ mod $23$, but $23=(x^3 - 2x^2 - 6x + 12)f-F$.
Mar
18
accepted Hurwitz’s construction of simple covers
Mar
18
comment Principal maximal ideals in Z[x]/(F)
Why the downvote - looks like an attractive question to me! (Now compensated by an upvote)
Mar
18
comment Hurwitz’s construction of simple covers
I don't mind getting a downvote - but still, a short explanation would be fine ...
Mar
18
answered Hurwitz’s construction of simple covers
Mar
17
comment All and the only algebraically closed fields s.t. any regular n-by-n matrix has a k-th root for every k
I don't know a reference, but I'm pretty sure that it should be at many places. Maybe mostly only over the complex numbers, but that doesn't make a difference. All we need is that the binomial coefficients $\binom{1/k}{i}$ exist in the base field.
Mar
17
accepted All and the only algebraically closed fields s.t. any regular n-by-n matrix has a k-th root for every k
Mar
17
answered All and the only algebraically closed fields s.t. any regular n-by-n matrix has a k-th root for every k
Mar
16
revised Subgroups of the general linear groups
added 332 characters in body
Mar
16
answered Subgroups of the general linear groups
Mar
8
revised Bolza curve admits no anticonformal fixedpointfree involution
added 43 characters in body
Mar
8
revised Bolza curve admits no anticonformal fixedpointfree involution
added 1611 characters in body
Mar
7
answered Bolza curve admits no anticonformal fixedpointfree involution
Mar
7
answered From reducible polynomial to an irreducible one