showing $k[x,y]\ncong k[u,v,w]/(uw-v^2)$
18484
Show that $k[x,y,z]/(xz-y^2)$ is not a UFD.
52596
A basis for $k(X)$ regarded as a vector space over $k$
33576
Non-principal ideal in $K[x,y]$?
124827
Show that $Y\sim N(a+A\mu,AVA^T)$
23037
Computing the order of $\mathrm{SL}_2(\mathbb F_p)$ as the kernel of $\mathrm{GL}_2(\mathbb F_p)$
156679
$K[X,Y]/(XY-1)$ not isomorphic to $K[T]$
155604
Show that $k[x,y]/(xy-1)$ is not isomorphic to a polynomial ring in one variable.
70249
Irreducibility of Polynomials in $k[x,y]$
94869
Show that $ \int_{k}^{2} \frac{1}{f(y)} =1$
46622
Let $ Y = \{ (1,1),(0,0\} \subset \mathbb A_k^2$. Find the $ \mathbb I(Y)$.
105170
About product of $k$ commutators
133087
Prove that, if $\{u,v,w\}$ is a basis for a vector space $V$, then so is $\{u+v, v+w, u+v+w\}$.
95513
Proving $W$ is a subspace of $P_{2}$
19424
Showing $(M^\perp)^\perp=\overline{M}$
17508
Knowing $|z|$ and $|w|$ (and possibly $z\overline{w}$), what are $|z+w|^2$, $|zw|^2$, $|z-w|^2$, $|z/w|^2$?
27564
Prove that $\|UVU^{-1}V^{-1}-I\|\leq 2\|U-I\|\|V-I\|$
143831
Showing $\mathbb{Q}$ is homeomorphic to $\mathbb{Q}^2$