Function: algprimesubalg
Section: algebras
C-Name: algprimesubalg
Prototype: G
Help: algprimesubalg(al): prime subalgebra of the positive characteristic,
semisimple algebra al.
Doc: \var{al} being the output of \tet{algtableinit} representing a semisimple
algebra of positive characteristic, returns a basis of the prime subalgebra
of~\var{al}. The prime subalgebra of~\var{al} is the subalgebra fixed by the
Frobenius automorphism of the center of \var{al}. It is abstractly isomorphic
to a product of copies of $\F_p$.
\bprog
? mt = [matid(3), [0,0,0; 1,1,0; 0,0,0], [0,0,1; 0,0,0; 1,0,1]];
? A = algtableinit(mt,2);
? algprimesubalg(A)
%3 =
[1 0]
[0 1]
[0 0]
@eprog