Is $\mathbb{Z}[t,t^{-1}]$ a PID? What about $\mathbb{Z}[\sqrt{2}i]$?
121986
Do the Laurent polynomials over $\mathbb{Z}$ form a principal ideal domain?
24351
The ring $\Bbb Z\left [\frac{-1+\sqrt{-19}}{2}\right ]$ is not a Euclidean domain
66020
What is $\mathbb Z[[t]]$? What are the double brackets?
93029
Prove that when $d$ is in $\mathbb{Q} \setminus\mathbb{Z}$, $\mathbb{Z}[\sqrt{d}]$ is not a finitely generated abelian group.
9223
Finding $\iiint_K (x^2 -z^2)\, dx\, dy \,dz$
32
Is $n^{th}$ root of $2$ an irrational number?
151127
Confirm that $\int_{0}^{\infty}t^{-1}\sin t dt=\pi/2$
111898
Is $\{ (e^{2\pi i a n},e^{2\pi i b n }) : n \in \mathbb{Z} \}$ dense in the torus, where $a,b$ irrationals such that $a/b$ irrational?
153664
When is $\Bbb{Z[\zeta_n]}$ a PID?
16507
Is $\mathbb{Z}= \{\dots -3, -2, -1, 0 ,1 ,2 , 3, \dots \}$ countable?
75970
$\mathbb Z[1/2]$ is not finitely generated?
83279
How can I find such a $z$? (Injectivity of $T(z) = \lambda z + \mu\bar{z}$)
154845
Irreducible elements in  $\mathbb{Z}[\sqrt{-2}]$ and is it a Euclidean domain?
12401
Is it standard to say $-i \log(-1)$ is $\pi$?
8434
Order of $\mathbb{Z}[i]/(1+i)$
126503
Showing that an integral domain is a PID if it satisfies two conditions
129732
What is $\operatorname{Aut}(\mathbb{Z}_2\oplus \mathbb{Z}_2)$?