>>> M1=mat_connexe_sym(3)
>>> M1
array([[0, 0, 1],
       [0, 0, 1],
       [1, 1, 0]])
>>> M2=mat_serveur_o(4)
>>> M2
array([[0, 1, 1, 1],
       [1, 0, 0, 0],
       [1, 0, 0, 0],
       [1, 0, 0, 0]])
>>> M=conca(M1,M2)
>>> M
array([[0, 0, 1, 0, 0, 0, 0],
       [0, 0, 1, 0, 0, 0, 0],
       [1, 1, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 1, 1, 1],
       [0, 0, 0, 1, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0]])
>>> lien_n(M,3)
array([[0, 0, 1, 0, 0, 0, 0],
       [0, 0, 1, 1, 0, 0, 0],
       [1, 1, 0, 0, 0, 0, 1],
       [0, 0, 0, 0, 1, 1, 1],
       [0, 0, 0, 1, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0]])