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Divisor :: isReflexive

isReflexive -- whether an ideal or module is reflexive



This function returns true if the module or ideal is reflexive, otherwise it returns false. In other words this checks if $M \cong Hom(Hom(M, R))$. This function calls reflexify and passes the options Strategy and KnownDomain specified in its call.

i1 : R = QQ[x,y,z]/ideal(x^2-y*z);
i2 : m = ideal(x,y,z);

o2 : Ideal of R
i3 : isReflexive(m)

o3 = false
i4 : isReflexive(m*R^1)

o4 = false
i5 : I = ideal(x,y);

o5 : Ideal of R
i6 : isReflexive(I)

o6 = true
i7 : isReflexive(I*R^1)

o7 = true

See also

Ways to use isReflexive :

For the programmer

The object isReflexive is a method function with options.