i1 : QQ[t_0..t_3]
o1 = QQ[t ..t ]
0 3
o1 : PolynomialRing
|
i2 : Phi = rationalMap {t_1^2+t_2^2+t_3^2,t_0*t_1,t_0*t_2,t_0*t_3}
o2 = -- rational map --
source: Proj(QQ[t , t , t , t ])
0 1 2 3
target: Proj(QQ[t , t , t , t ])
0 1 2 3
defining forms: {
2 2 2
t + t + t ,
1 2 3
t t ,
0 1
t t ,
0 2
t t
0 3
}
o2 : RationalMap (quadratic rational map from PP^3 to PP^3)
|
i3 : map Phi
2 2 2
o3 = map (QQ[t ..t ], QQ[t ..t ], {t + t + t , t t , t t , t t })
0 3 0 3 1 2 3 0 1 0 2 0 3
o3 : RingMap QQ[t ..t ] <--- QQ[t ..t ]
0 3 0 3
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The command map Phi is equivalent to map(0,Phi). More generally, the command map(i,Phi) returns the i-th representative of the map Phi.