multidegree(MultirationalMap) -- projective degrees of a multi-rational map

Synopsis

• Function: multidegree

• Usage:

  multidegree Phi

• Inputs:
  • Phi, a multi-rational map
• Outputs:
  • a list, the list of projective degrees of Phi

Description

This calculates the multidegree of the graph and converts it to the list of projective degrees.

i1 : ZZ/300007[x_0..x_3], f = rationalMap {x_2^2-x_1*x_3, x_1*x_2-x_0*x_3, x_1^2-x_0*x_2}, g = rationalMap {x_1^2-x_0*x_2, x_0*x_3, x_1*x_3, x_2*x_3, x_3^2};

i2 : Phi = last graph rationalMap {f,g};

o2 : MultirationalMap (rational map from threefold in PP^3 x PP^2 x PP^4 to PP^2 x PP^4)

i3 : time multidegree Phi
 -- used 0.360049s (cpu); 0.277719s (thread); 0s (gc)

o3 = {66, 46, 31, 20}

o3 : List

i4 : (degree source Phi,degree image Phi)

o4 = (66, 20)

o4 : Sequence

References

See also

• multidegree(ZZ,MultirationalMap) -- i-th projective degree of a multi-rational map using a probabilistic approach
• multidegree(RationalMap) -- projective degrees of a rational map
• degree(MultirationalMap) -- degree of a multi-rational map
• projectiveDegrees(RationalMap) -- projective degrees of a rational map