Anti-diagonal matrix
In mathematics, an anti-diagonal matrix is a square matrix where all the entries are zero except those on the diagonal going from the lower left corner to the upper right corner (↗), known as the anti-diagonal (sometimes Harrison diagonal, secondary diagonal, trailing diagonal, minor diagonal, off diagonal or bad diagonal). == Formal definition == An n × n matrix A is an anti-diagonal matrix if the (i, j)th element aij is zero for all rows i and columns j whose indices do not sum to n + 1.