IsAntidiagonal
Tests if a matrix is antidiagonal.
Syntax

IsAntidiagonal(A[, ε])

A
is a matrix 
ε
is a positive number

Description
If A
is a matrix then IsAntidiagonal(A, ε)
is true
iff A
is square and i ≠ n − j + 1 implies A[i, j] is zero (with epsilon ε
) where n
is the size of A
.
Examples
IsAntidiagonal(❨❨0, 4❩, ❨1, 0❩❩)
true