i1 : R = ZZ/31991[a,b,c,d]; |
i2 : I = monomialCurveIdeal(R,{1,3,5}) 2 2 2 3 2 o2 = ideal (c - b*d, b c - a d, b - a c) o2 : Ideal of R |
i3 : projplane = Proj(R) o3 = projplane o3 : ProjectiveVariety |
i4 : II = sheaf module I o4 = image | c2-bd b2c-a2d b3-a2c | 1 o4 : coherent sheaf on projplane, subsheaf of OO projplane |
i5 : can = sheafExt^1(II,OO_projplane^1(-4)) o5 = cokernel | c b a2 | | d c b2 | 2 o5 : coherent sheaf on projplane, quotient of OO projplane |
i6 : codim can o6 = 2 |