Wedderburn decomposition of commutative finite dimensional algebras via GAP
Let $R$ be a commutative finite dimensional $K$-algebra over a field $K$ (for example the monoid ring of a a finite monoid over a field). Assume we have $R$ in GAP. Then we can check whether $R$ is semisimple using the command RadicalOfAlgebra(R). When the value is 0, $R$ is semisimple. Thus $R$ can be written as a finite product of finite field extensions of $K$.
Question: Can we obtain those finite field extensions of $K$ or at least their number and $K$-dimensions using GAP?
If you are working over a finite field, and can represent the algebra through matrices, you could try to split the regular module into its homogeneous components. This can be done with the GAP command MTX.Indecomposition
. You then take a simple submodule in this component (try a spin of a random vector), and take the action of the homogeneous component on this module (and should let you deduce the appropriate field extension).
(If you add an example, I can try to show the corresponding GAP commands.)