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Macaulay2Doc > substitution and maps between rings > graphRing(RingMap)

graphRing(RingMap) -- the coordinate ring of the graph of the regular map corresponding to a ring map

Synopsis

Description

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 : graphRing f

            QQ[p , p , p , p , p ]
                0   1   2   3   4
o4 = -----------------------------------
         2                       2
     (- p  + p , - p p  + p , - p  + p )
         0    2     0 1    3     1    4

o4 : QuotientRing
i5 : Spec oo

         /       QQ[p , p , p , p , p ]      \
         |           0   1   2   3   4       |
o5 = Spec|-----------------------------------|
         |    2                       2      |
         |(- p  + p , - p p  + p , - p  + p )|
         \    0    2     0 1    3     1    4 /

o5 : AffineVariety

See also