1,754 reputation
1829
bio website anhhuy.ch
location Switzerland
age 21
visits member for 3 years, 4 months
seen 12 hours ago

My name is Anh Huy Truong and I am currently studying mathematics at the ETH Zürich.


Aug
21
comment Proving Sylow's first theorem
Yes, $S_i$ is not necessarily a subgroup. That is the point of the equation $\operatorname{Stab}_G(S_i) = S_i$: As the stabilizer IS a subgroup, it implies that $S_i$ is too.
Aug
21
comment Proving Sylow's first theorem
Aren't order and cardinality of sets the same thing?
Aug
21
comment Proving Sylow's first theorem
Yes, I meant that $p$ cannot divide the cardinality of the orbit $S_i$ (I never said order, did I?). Also, I fixed a mistake. The way I understand the proof is that we have an orbit such that $p$ doesn't divide its cardinality and then find $\operatorname{Stab}_G(S_i) = S_i$ (but I don't know why this equation holds). This equation implies that the stabilizer and $S_i$ have the same cardinality and as the stabilizer is a subgroup (of cardinality $p^n$), we are done.
Aug
21
revised Proving Sylow's first theorem
added 1 characters in body
Aug
21
comment Proving Sylow's first theorem
$S_i$ only represents the orbit $GS_i$.
Aug
21
revised Proving Sylow's first theorem
added 15 characters in body
Aug
21
asked Proving Sylow's first theorem
Aug
16
asked Concerning the distribution of a random variable of a random walk that doesn't make any sense to me
Jul
30
awarded  Nice Question
Jul
25
accepted Differentiating terms involving evaluation operator and Wronski matrix
Jul
25
comment Differentiating terms involving evaluation operator and Wronski matrix
Why does $D\Phi^T(z) = \frac{\partial}{\partial y} \Phi^{T}y|_{y=z}$? Is this because $\Phi^T(z)$ does not depend on the time variable?
Jul
25
accepted What is an evaluation operator and what is its use?
Jul
25
asked Differentiating terms involving evaluation operator and Wronski matrix
Jul
22
awarded  Popular Question
Jul
3
accepted Construction of field extensions
Jul
3
comment Construction of field extensions
I see. The use of $X$ as both a variable and a polynomial caused the confusion.
Jul
3
comment Construction of field extensions
Just after submitting this question, it came to my mind that in the definition $a:=X+(P)$, the $X$ is probably not meant as a variable, but as the polynomial $X \in K[X]$, right?
Jul
3
asked Construction of field extensions
Jul
1
asked For $k$ a field, show that every finite subgroup $\mu$ of $k^\times$ is cyclic
Jun
27
accepted Application of the Chinese Remainder Theorem