Saturday 26 May 2007

ac.commutative algebra - Computational Question about finite local rings:

Let $(A,mathfrak{m})$ be a local Artinian ring with
finite residue field, which I'm happy to assume is $mathbf{F}_3$.
(In particular, $A$ has finitely many elements.)



I would like to do some computations of the following kind, as $I$ ranges over
all of the ideals of $A$.



(0) A way to enumerate all the ideals of $A$.



(1) For an ideal $I$ of $A$, compute the length of $I/I^2$.



(2) For an ideal $I$ of $A$, compute the ideal $J = mathrm{Ann}(I)$.



(3) For an ideal $I$ of $A$, decide if $I$ is principal. (By computing the length of
$I/mathfrak{m} I$ or otherwise.)



The ring $A$ itself will be given explicitly as a quotient of a power series
ring over $W(mathbf{F}_3) = mathbf{Z}_3$. For example, $A$ might be
given as $mathbf{Z}_3[[x]]/(27,9x,x^3)$ or $mathbf{Z}_3[[x]]/(9,x^2)$.



My question: What is the computer algebra package that is best suited to carry
out these computations? (I would like something that can be semi-automated for various possible $A$.) I would be interested in even a very simple one like $mathbf{Z}_3[[x]]/(9,x^2)$



EDIT 2: There seems to be a consensus in the comments that this problem is significantly more manageable if $A$ is actually an algebra over its residue field. For example, in MAGMA, it is only possible to create ideals and quotient rings in univariate polynomial rings over fields. Other computer algebra packages have similar issues when the coefficient ring is not a field, although SINGULAR (for example) has some functionality with polynomials in several variables. As it happens, the problem I was interested in studying is still of interest for such fields.

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