I have commutative rational algebras that are supposed to be semisimple
over some cyclotomic field. How can I find this structure? Extending
coefficients to "Cyclotomics" and using "CentralIdempotentsOfAlgebra" gives
a crash, apparently because GAP cannot factor polynomials over cyclotomics.

Is there some way to find where the implementation of a function is in the
library? For instance material related to structure constant tables for
algebras occurs in at least three different files. Reading the code can be
very helpful, but I can't always find it.

Thanks, Frank Quinn