1. The identity matrix Commutes with all matrices.

2. So A times A inverse should also be equal to the identity matrix.

3. To Absorbing states, Q is the square submatrix giving these probabilities from non- Absorbing to non-Absorbing states, I is an identity matrix, and 0 is a rectangular matrix of zeros

4. A matrix Commutes with every other matrix if and only if it is a scalar matrix, that is, a matrix of the form , where is the identity matrix, and is a scalar

5. 178 8 Copulas correlation matrix is the identity matrix, so that all correlations are zero, is the d-dimensional independence Copula.A Gaussian Copula will converge to the co-monotonicity Copula if all correlations in › converge to 1