extractEntries -- Inverse of moduleToSubringIdeal

Synopsis

• Usage:
result = extractEntries(M, gVars)
• Inputs:
• M, , a 1-column matrix of elements of a subring ideal
• gVars, , a 1-row matrix containing the variables that correspond to the generators of the module.
• Outputs:
• result, ,

Description

Converts elements of a subring ideal (represented by a one-column matrix and usually generated by moduleToSubringIdeal) to elements of a module (represented by a matrix).

Internally, the argument gVars is sorted so that the order of the columns of the resulting matrix are consistent.

 i1 : R = QQ[a, b, c, x_1, x_2, x_3]; i2 : extractEntries(matrix {{a*x_1 + b*x_2 + c*x_3}}, matrix {{x_1, x_2, x_3}}) o2 = | c b a | 1 3 o2 : Matrix R <--- R i3 : extractEntries(matrix {{a*x_1 + b*x_2 + c*x_3},{a*x_1 + a*x_2 + a*x_3}}, matrix {{x_1, x_2, x_3}} ) o3 = | c b a | | a a a | 2 3 o3 : Matrix R <--- R