toRationalMap -- convert a multi-rational map consisting of a single rational map to a standard rational map

Synopsis

• Usage:

  toRationalMap Phi

• Inputs:
  • Phi, a multi-rational map, whose target is an embedded projective variety
• Outputs:
  • a rational map, which is mathematically equal to Phi but represented as an object of the class RationalMap

Description

This is useful when you need to use tools from the package Cremona.

i1 : Phi = rationalMap(PP_QQ^(1,4),Dominant=>true);

o1 : MultirationalMap (dominant rational map from PP^4 to hypersurface in PP^5)

i2 : class Phi

o2 = MultirationalMap

o2 : Type

i3 : f = toRationalMap Phi;

o3 : RationalMap (quadratic dominant rational map from PP^4 to hypersurface in PP^5)

i4 : class f

o4 = RationalMap

o4 : Type

i5 : assert(Phi == f and Phi =!= f)

See also

• multirationalMap(RationalMap) -- Some convenient shortcuts for multi-rational maps consisting of a single rational map