In a commutative ring $A$, $IJ=JI$ where $I$ and $J$ are two ideals of $A$.
But if $A$ is not commutative is it true?? $IJ$ is the product of ideals $I$ and $J$.
In a commutative ring $A$, $IJ=JI$ where $I$ and $J$ are two ideals of $A$.
But if $A$ is not commutative is it true?? $IJ$ is the product of ideals $I$ and $J$.
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Hint:
One might try something obvious like $R=\mathbb Z\langle x,y\rangle/(x^2, xy, y^2)$.
Let $I=(x)$ and $J=(y)$ and compute what these ideals look like and what their products look like, in both orders.