NCMatrix - NCMatrix -- Subtract NCMatrices

i1 : A = QQ{x,y,z}

o1 = A

o1 : NCPolynomialRing

i2 : M = ncMatrix {{x, y, z}}

o2 = | x y z |

o2 : NCMatrix

i3 : sigma = ncMap(A,A,{y,z,x})

o3 = NCRingMap A <--- A

o3 : NCRingMap

i4 : N = ncMatrix {{M},{sigma M}, {sigma sigma M}}

o4 = | x y z |
     | y z x |
     | z x y |

o4 : NCMatrix

i5 : N' = ncMatrix {{sigma sigma M}, {sigma M}, {M}}

o5 = | z x y |
     | y z x |
     | x y z |

o5 : NCMatrix

i6 : N - N'

o6 = | -z+x y-x  z-y  |
     | 0    0    0    |
     | z-x  -y+x -z+y |

o6 : NCMatrix