Ben

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From the Bay to LA.


56 Answers

newest activity votes
12
If $N$ and $M$ are normal subgroups and $N$ and $M$ have no common element other than $e$ then prove that for all $m \in M$ and $n\in N$, $mn=nm$.
10
Does $\sin^2 x - \cos^2 x = 1-2\cos^2 x$?
10
Why do the gaussian integers have only 2 congruence classes mod 1+i?
7
A finite group of even order has an odd number of elements of order 2
6
Does every noninvertible element of a commutative ring lie in a proper maximal ideal?
5
For which Natural $n\ge2: \phi(n)=n/2$
5
If $|f|$ is constant, so is $f$ for $f$ analytic on a domain $D$.
5
How to prove that $\mathbb R [x]$ is a UFD
4
If $H,K \leq G$ a finite group, then $\left\lvert HK \right\rvert = \cdots$
4
Does a linear map $L: V \to W$ have nontrivial kernel if $\dim V > \dim W$
4
Advice? homework: $\forall x,y \in \mathbb{R}, x \in \mathbb{Q} \land y \notin \mathbb{Q} \implies (x + y) \notin \mathbb{Q}$
4
On Group action and blocks of subgroups of the symmetric Group
4
A Question on $p$-groups.
4
Isomorphism between quotient modules
4
Show that if $a\neq 0$ in $M_2(\Bbb{R})$, the smallest ideal containing $a$ is the ring itself
3
Solvability of a group with order $p^n$
3
Prove: $a\equiv b\pmod{n} \implies \gcd(a,n)=\gcd(b,n)$
3
Finding the image of $D=\{z|\,-\frac{\pi}{2}<Re(z)<\frac{\pi}{2}\}$ under $f(z)=e^{iz}$
3
$S\subseteq V \Rightarrow \text{span}(S)\cong S^{00}$
3
$V$ is isomorphic to $V^{\ast\ast}$, the double dual space of $V$.
3
Proving $\sqrt[6]{2}\not\in\mathbb{Q}(\sqrt[3]{2})$
3
prove : if $G$ is a finite group of order $n$ and $p$ is the smallest prime dividing $|G|$ then any subgroup of index $p$ is normal
3
Finding the derivative of an integral
3
Showing $x^n=\alpha$ has $n$ solutions in a field extension of degree $n$.
3
Centre of a matrix ring are diagonal matrices
3
A problem about direct product
3
Suppose F is a field, and $f: F_F \to M$ is a non-zero homomorphism. Show that f is injective
3
Elementary proof that $3$ is a primitive root of a Fermat prime?
2
On Group of order $30$ and $60$.
2
A proof in Algebra
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