This function is provided by the package InvariantRing.
i1 : R = QQ[x_1..x_4] o1 = R o1 : PolynomialRing |
i2 : T = diagonalAction(matrix {{0,1,-1,1},{1,0,-1,-1}}, R)
* 2
o2 = R <- (QQ ) via
| 0 1 -1 1 |
| 1 0 -1 -1 |
o2 : DiagonalAction
|
i3 : dim T == dim R o3 = true |