import numpy as np
import numpy.linalg as alg

A3 = np.array([[0,-4,12],[4,0,-3],[-12,3,0]])
N = np.dot(alg.inv(np.eye(3)-A3),np.eye(3)+A3)
# print(np.dot(N,N.T),alg.det(N))

A4 = np.array([[0,1,3,-3],[-1,0,-4,0],[-3,4,0,2],[3,0,-2,0]])
M = np.dot(alg.inv(np.eye(4)-A4),np.eye(4)+A4)
# print(np.dot(M,M.T),alg.det(M))