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PushForward :: pushFwd(RingMap)

pushFwd(RingMap) -- push forward of a finite ring map

Synopsis

Description

i1 : kk = QQ

o1 = QQ

o1 : Ring
i2 : S = kk[a..d]

o2 = S

o2 : PolynomialRing
i3 : I = monomialCurveIdeal(S, {1,3,4})

                        3      2     2    2    3    2
o3 = ideal (b*c - a*d, c  - b*d , a*c  - b d, b  - a c)

o3 : Ideal of S
i4 : R = S/I

o4 = R

o4 : QuotientRing
i5 : A = kk[a,d]

o5 = A

o5 : PolynomialRing
i6 : use R

o6 = R

o6 : QuotientRing
i7 : F = map(R,A)

o7 = map(R,A,{a, d})

o7 : RingMap R <--- A
i8 : pushFwd F

o8 = (cokernel {0} | 0  |, | 1 b b2 c c2 |,
               {1} | 0  |
               {2} | -d |
               {1} | 0  |
               {2} | a  |
     ------------------------------------------------------------------------
     {*Function[/home/dan/src/M2/1.6/M2/Macaulay2/packages/PushForward.m2:191
     ------------------------------------------------------------------------
     :15-193:15]*})

o8 : Sequence