1
How can I prove that the ring of all $2*2$ matrices $$\begin{equation*}
\begin{bmatrix}
a & b \\
0 & c
\end{bmatrix} \qquad
\end{equation*}$$
Such that $a$ is an integer and $b,c$ are rationals is right Noetherian but not left Noetherian. I have seen a lot of discussions here about it but I sti...
