Definition:Matrix/Diagonal/Main Antidiagonal

Definition

Let $\mathbf A = \sqbrk a_{m n}$ be a matrix.

The main antidiagonal of $\mathbf A$ is the antidiagonal of $\mathbf A$ from the top right corner, that is, the element $a_{1 n}$, running towards the lower left corner.

Also known as

The main antidiagonal of an array (such as a matrix or a determinant) is also known as its secondary diagonal.

Also see

• Results about the main antidiagonal can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): matrix (plural matrices)
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): main diagonal, main antidiagonal