DividedPowers -- Option for inverseSystem

Functions with optional argument named DividedPowers:

• fromDual(...,DividedPowers=>...) -- see fromDual -- Ideal from inverse system
• inverseSystem(...,DividedPowers=>...) -- see inverseSystem -- Inverse systems with equivariance
• toDual(...,DividedPowers=>...) -- see toDual -- finds the inverse system to an ideal up to a given degree