Some of this article's listed sourcesmay not be reliable. Please help this article by looking for better, more reliable sources. Unreliable citations may be challenged or deleted.(December 2021) (Learn how and when to remove this template message)
In linear algebra, the main diagonal (sometimes principal diagonal, primary diagonal, leading diagonal, major diagonal, or good diagonal) of a matrix is the list of entries where . All off-diagonal elements are zero in a diagonal matrix. The following three matrices have their main diagonals indicated by red ones:
The antidiagonal (sometimes counter diagonal, secondary diagonal, trailing diagonal, minor diagonal, off diagonal, or bad diagonal) of an order square matrix is the collection of entries such that for all . That is, it runs from the top right corner to the bottom left corner.