1. ## Matrix help

Hi, can you please explain to me the following

Thank you

Maths

2. Originally Posted by Maths
Hi, can you please explain to me the following

Thank you

Maths
$S$ is not an ideal (left or right) because it doesn't have the absorbing property ( $\forall A\in S$, $B\in R$, $B\cdot A\in S$).