This function returns the genus of a curve embedded in P1*P2 by computing the genus of its image under the Segre embedding in P5.
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 : Y1=ideal(random(S^1,S^{{-3,-1},{-1,-2}}));
o4 : Ideal of S
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i5 : genusP1P2(Y1) o5 = 3 |
i6 : Y2=ideal(random(S^1,S^{{-1,0},{0,-9}}));
o6 : Ideal of S
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i7 : genusP1P2(Y2) o7 = 28 |