. This function returns the defining ideal of the ring of
.
i1 : R = QQ[w,x,y,z];
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i2 : X = Spec(R/(y^2-x*z,x^2*y-z^2,x^3-y*z))
o2 = X
o2 : AffineVariety
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i3 : ideal X
2 2 2 3
o3 = ideal (y - x*z, x y - z , x - y*z)
o3 : Ideal of R
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i4 : ring X
R
o4 = ------------------------------
2 2 2 3
(y - x*z, x y - z , x - y*z)
o4 : QuotientRing
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i5 : Y = Proj(R/(x^2-w*y, x*y-w*z, x*z-y^2))
o5 = Y
o5 : ProjectiveVariety
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i6 : ideal Y
2 2
o6 = ideal (x - w*y, x*y - w*z, - y + x*z)
o6 : Ideal of R
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