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Cremona :: toExternalString(RationalMap)

toExternalString(RationalMap) -- convert to a readable string

Synopsis

Description

All internal data of the input are included in the returned string.

i1 : phi = (specialCubicTransformation(2,ZZ/33331))!;

o1 : RationalMap (cubic birational map from PP^3 to hypersurface in PP^4)
i2 : str = toExternalString phi;
i3 : #str

o3 = 7432
i4 : time phi' = value str;
     -- used 0.0136545 seconds

o4 : RationalMap (cubic birational map from PP^3 to hypersurface in PP^4)
i5 : time describe phi'
     -- used 0.00456962 seconds

o5 = rational map defined by forms of degree 3
     source variety: PP^3
     target variety: smooth quadric hypersurface in PP^4
     dominance: true
     birationality: true (the inverse map is already calculated)
     projective degrees: {1, 3, 4, 2}
     number of minimal representatives: 1
     dimension base locus: 1
     degree base locus: 5
     coefficient ring: ZZ/33331
i6 : time describe inverse phi'
     -- used 0.00549712 seconds

o6 = rational map defined by forms of degree 2
     source variety: smooth quadric hypersurface in PP^4
     target variety: PP^3
     dominance: true
     birationality: true (the inverse map is already calculated)
     projective degrees: {2, 4, 3, 1}
     number of minimal representatives: 1
     dimension base locus: 1
     degree base locus: 5
     coefficient ring: ZZ/33331