3,385 reputation
1625
bio website stefuzius.wordpress.com
location
age
visits member for 2 years, 9 months
seen 13 hours ago

stefuzius84 (at) web (dot) de


1d
accepted Proof about the Sylow $2$-subgroups of permutation group such that each element has at most two fixed points
1d
comment Proof about the Sylow $2$-subgroups of permutation group such that each element has at most two fixed points
Ah okay semiregular means fixed point free, I found another (of course equivalent) definition. Also that $d = 2$ has nothing to do with $n \ge 1$ and the size of $\Delta$ as written later, so this was a little bit misleading. Thank you for your clear explanation!
1d
asked Proof about the Sylow $2$-subgroups of permutation group such that each element has at most two fixed points
2d
comment How can I interpret the ratio $\frac{f(x_0)}{f'(x_0)}$?
In your link the quotient of $f(x_n)$ and $f'(x_n)$ beneath the picture is written in the wrong order.
2d
comment I hhave to show $D^n =\ker f⊕\ker g$
This does not hold, please clarify your question. For a counterexample consider $$ A = \begin{pmatrix} 2 & 0 \\ 0 & 3 \end{pmatrix}. $$ Then $\mbox{ker}(f) = \{0\}$ and $\mbox{ker}(g) = \{0\}$, so their direct sum equals the trivial space too. And by the way, you should mention what $D$ denotes, an arbitrary field, or something specific?
2d
accepted Two Lemmata about permutation groups such that every element has at most two fixed points
2d
comment Two Lemmata about permutation groups such that every element has at most two fixed points
In your first paragraph, the next to last sentence: "[...] in which a point stabilizer has index $2$ [...]". Why that?
2d
asked Two Lemmata about permutation groups such that every element has at most two fixed points
Mar
23
accepted A sufficient criterion for a finite group to be a Frobenius group
Mar
23
comment A sufficient criterion for a finite group to be a Frobenius group
Do you really mean $P\le N_H(Z(P))$ or $P \le N_G(Z(P))$? And yes, thanks I corrected my misspelling!
Mar
23
revised A sufficient criterion for a finite group to be a Frobenius group
edited body; edited title
Mar
23
asked A sufficient criterion for a finite group to be a Frobenius group
Mar
22
accepted Argument about the size of Frobenius kernel, question on derivation
Mar
22
asked Argument about the size of Frobenius kernel, question on derivation
Mar
19
accepted Proof that the clopen subsets of $A^{\mathbb N}$ are finite unions using König's Lemma
Mar
18
revised Basic Survival Facts in Finite Group Theory
added 230 characters in body
Mar
18
comment Basic Survival Facts in Finite Group Theory
Yes, that's what I meant :)
Mar
18
comment Basic Survival Facts in Finite Group Theory
@MJD: Yes, what you first mentioned is such a fact. Such things that are sometimes not explicitly mentioned, but used. Yes you need to know the Sylow theorems to apply the other fact, but it is a fact so basic that is does not even need to mentioned in follow up proofs (after exposed to the Sylow theorems), so that a novice who first heard about Sylow theorems might stumble upon if he has not fully internalised all of them, do you get what I mean? Not basic in the sense of logical derivation, but basic in the sense, used by practitioners over and over again (and could involve advanced notion).
Mar
18
comment Basic Survival Facts in Finite Group Theory
To be strict, it should be included, but in fact this is so elementary that I even did not considered it. So maybe we should restrict on facts that are simple, but not so much that you could read them everywhere, more such kind of facts novices stumble upon, but which become obvious as you become more aquainted with the topic.
Mar
18
revised Proof that the clopen subsets of $A^{\mathbb N}$ are finite unions using König's Lemma
added 2 characters in body