(quote _,Matrix,List)

f_{i,j,k,...} -- produce the submatrix of a matrix f consisting of columns numbered i, j, k, ... .

Repetitions of the indices are allowed.

If the list of column indices is a permutation of 0 .. n-1, where n is the number of columns, then the result is the corresponding permutation of the columns of f.

i1 : R = ZZ/101[a..f];

i2 : p = matrix {{a,b,c},{d,e,f}}



o2 = {0} | a b c |

     {0} | d e f |



             2       3

o2 : Matrix R  <--- R

i3 : p_{1}



o3 = {0} | b |

     {0} | e |



             2       1

o3 : Matrix R  <--- R

i4 : p_{1,1,2}



o4 = {0} | b b c |

     {0} | e e f |



             2       3

o4 : Matrix R  <--- R

i5 : p_{2,1,0}



o5 = {0} | c b a |

     {0} | f e d |



             2       3

o5 : Matrix R  <--- R