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adjoint1(Matrix,Module,Module) -- an adjoint map

Synopsis

Description

All modules should be free modules over the same base ring, and the rank of the target of f should be the product of the ranks of G and H. Recall that ** refers to the tensor product of modules, and that dual G is a free module with the same rank as G.

No computation is required. The resulting matrix has the same entries as f, but in a different layout.

If f is homogeneous, and target f == G ** H,including the grading, then the resulting matrix will be homogeneous.

i1 : R = QQ[x_1 .. x_12];
i2 : f = genericMatrix(R,6,2)

o2 = | x_1 x_7  |
     | x_2 x_8  |
     | x_3 x_9  |
     | x_4 x_10 |
     | x_5 x_11 |
     | x_6 x_12 |

             6       2
o2 : Matrix R  <--- R
i3 : g = adjoint1(f,R^2,R^3)

o3 = | x_1 x_4 x_7 x_10 |
     | x_2 x_5 x_8 x_11 |
     | x_3 x_6 x_9 x_12 |

             3       4
o3 : Matrix R  <--- R
i4 : isHomogeneous g

o4 = true

See also