This function computes the plane model of C under the second projection map and checks that the plane model has only ordinary double points as singularities.
i1 : p=101; |
i2 : Fp=ZZ/p; |
i3 : S=Fp[x_0,x_1,y_0..y_2,Degrees=>{2:{1,0},3:{0,1}}];
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i4 : pt=ideal random(S^1,S^{{-1,0},{0,-1},{0,-1}});
o4 : Ideal of S
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i5 : Y1=ideal(gens pt * random(source gens pt,S^{{-1,-1},{-1,-1}}));
o5 : Ideal of S
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i6 : Y2=ideal(gens pt * random(source gens pt,S^{{-1,0},{0,-1}}));
o6 : Ideal of S
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i7 : Y3=ideal(gens pt * random(source gens pt,S^{{-1,-1},{-2,-1}}));
o7 : Ideal of S
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i8 : isOrdDoublePoints(Y1) o8 = true |
i9 : isOrdDoublePoints(Y2) o9 = true |
i10 : isOrdDoublePoints(Y3) o10 = true |
i11 : isOrdDoublePoints(intersect({Y1,Y2}))
o11 = true
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i12 : isOrdDoublePoints(intersect({Y1,Y2,Y3}))
o12 = false
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