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Divisor :: dualizeIdeal

dualizeIdeal -- Finds an ideal isomorphic to Hom(I, R)

Synopsis

Description

Get the double dual (S2 - identification) of an ideal. If KnownNormal is false (default is true), then the computer will first check whether the ambient ring is normal, if it is not then it will perform a (possibly) slower check that will definitely give the right answer.
i1 : R = QQ[x,y,z]/ideal(x^2-y*z)

o1 = R

o1 : QuotientRing
i2 : m = ideal(x,y,z)

o2 = ideal (x, y, z)

o2 : Ideal of R
i3 : dualizeIdeal(m)

o3 = ideal x

o3 : Ideal of R
i4 : I = ideal(x,y)

o4 = ideal (x, y)

o4 : Ideal of R
i5 : dualizeIdeal(I)

o5 = ideal (z, x)

o5 : Ideal of R
i6 : dualizeIdeal(I^2)

o6 = ideal z

o6 : Ideal of R
i7 : dualizeIdeal(I^3)

             2
o7 = ideal (z , x*z)

o7 : Ideal of R

See also

Ways to use dualizeIdeal :