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Cremona :: graph(RingMap)

graph(RingMap) -- closure of the graph of a rational map

Synopsis

Description

i1 : phi = map(QQ[x_0..x_3],QQ[y_0..y_2],{-x_1^2+x_0*x_2,-x_1*x_2+x_0*x_3,-x_2^2+x_1*x_3})

                                   2                           2
o1 = map(QQ[x ..x ],QQ[y ..y ],{- x  + x x , - x x  + x x , - x  + x x })
             0   3      0   2      1    0 2     1 2    0 3     2    1 3

o1 : RingMap QQ[x ..x ] <--- QQ[y ..y ]
                 0   3           0   2
i2 : graph phi

                     QQ[x ..x , y ..y ]                                   
                         0   3   0   2                                    
o2 = (map(----------------------------------------,QQ[x ..x ],{x , x , x ,
          (x y  - x y  + x y , x y  - x y  + x y )     0   3    0   1   2 
            3 0    2 1    1 2   2 0    1 1    0 2                         
     ------------------------------------------------------------------------
                          QQ[x ..x , y ..y ]
                              0   3   0   2
     x }), map(----------------------------------------,QQ[y ..y ],{y , y ,
      3        (x y  - x y  + x y , x y  - x y  + x y )     0   2    0   1 
                 3 0    2 1    1 2   2 0    1 1    0 2
     ------------------------------------------------------------------------
     y }))
      2

o2 : Sequence

See also