Computes the Eagon-Northcott type resolution associated to the matrix Phi defining the scroll and an integer b defining the twist $O_{P(E)}(bR)$. The way the function works is similar to the way the "Eagon-Northcott" function by Greg Smith works.
i1 : R = ZZ/12347[x_0..x_7] o1 = R o1 : PolynomialRing |
i2 : Phi = matrix{{x_0..x_3},{x_4..x_7}}
o2 = | x_0 x_1 x_2 x_3 |
| x_4 x_5 x_6 x_7 |
2 4
o2 : Matrix R <--- R
|
i3 : betti(eagonNorthcottType(Phi,0))
0 1 2 3
o3 = total: 1 6 8 3
0: 1 . . .
1: . 6 8 3
o3 : BettiTally
|
i4 : betti(eagonNorthcottType(Phi,1))
0 1 2 3
o4 = total: 2 4 4 2
0: 2 4 . .
1: . . 4 2
o4 : BettiTally
|
The object eagonNorthcottType is a method function.