1. The Diagonal

What is the standard notation for the diagonal of a matrix? I believe it is $\Delta$, as with the cartesian product, but I am not sure.

If so, is there another notation for it? As I'm using $\Delta$ for something else...

2. Standard Notation?

I believe delta is used when your looking for the determinant of a matrix.

3. Originally Posted by gotpho
Standard Notation?

I believe delta is used when your looking for the determinant of a matrix.
I've never heard of that - can you perhaps give an example?