The command ElementwiseNot(M) performs an element-wise logical not on M.

For matrix M, the result R is a matrix where  R[i,j] = 1, if M[i,j] = 0, and R[i,j] = 0 otherwise.

For scalar M, the result R = 1, if M is 0, and R = 0 otherwise.

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$M≔\mathrm{Matrix}\left(\left[\left[-1\,0\right]\,\left[3\,0\right]\right]\right)\:$

$\mathrm{ElementwiseNot}\left(M\right)$

$\left[\begin{array}{cc}0& 1\\ 0& 1\end{array}\right]$