Talk:Square Matrix with Duplicate Rows has Zero Determinant/Proof 2

This proof needs to start with some assumption of what $R$ is. The proof claims that $-D = D$ implies $D=0$, which is not generally true for commutative rings. For instance, in $\Z$ modulo $12$, we have $6 = -6$. I suggested that we assume that $R$ is a subfield of $\C$ - it is possible to make broader assumptions, but I have already uploaded a proof that should work for all commutative rings. Anyone have a better suggestion of what the assumption should be? --Anghel (talk) 17:17, 8 January 2013 (UTC)


 * How careless of me. Sorry. --abcxyz (talk) 17:32, 8 January 2013 (UTC)