Given an ideal $I$, we can determine if $I^{(m)} \subseteq I^n$. For example, here is an ideal that fails the containment $I^{(3)} \subseteq I^2$:
i1 : B = ZZ/101[x,y,z]; |
i2 : I = ideal(x*(y^3-z^3),y*(z^3-x^3),z*(x^3-y^3)); o2 : Ideal of B |
i3 : isSymbPowerContainedinPower(I,3,2) o3 = false |
We can also determine the smallest symbolic power contained in a given power.
In our example, $I^{(4)}$ is the smallest symbolic power contained in $I^2$:
i4 : containmentProblem(I,2) o4 = 4 |
We can ask the same question backwards: what is the largest power of I that contains $I^{(4)}$?
i5 : containmentProblem(I,4,InSymbolic => true) o5 = 2 |