graphIdeal(RingMap) -- the ideal of the graph of the regular map corresponding to a ring map

• Function: graphIdeal

• Usage:

  graphIdeal f

• Inputs:
  • f, a ring map
• Optional inputs:
  • MonomialOrder => ..., default value {GRevLex, Position => Up}, a monomial ordering, see monomial orderings
  • MonomialSize => an integer, default value 32, the monomial size, see MonomialSize
  • VariableBaseName => a symbol, default value "p", the variable base name, see VariableBaseName
• Outputs:
  • an ideal, the ideal of the graph of regular map corresponding to f

i1 : R = QQ[x,y]

o1 = R

o1 : PolynomialRing

i2 : S = QQ[s,t,u]

o2 = S

o2 : PolynomialRing

i3 : f = map(R,S,{x^2,x*y,y^2})

                  2        2
o3 = map (R, S, {x , x*y, y })

o3 : RingMap R <-- S

i4 : graphIdeal f

               2                       2
o4 = ideal (- p  + p , - p p  + p , - p  + p )
               0    2     0 1    3     1    4

o4 : Ideal of QQ[p ..p ]
                  0   4