gap> C3 := CyclicGroup(3);
<pc group of size 3 with 1 generators>
gap> A := Algebra(Rationals, GeneratorsOfGroup(C3));
<algebra over Rationals, with 1 generators>

gap> Dimension(A);
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `IsFiniteDimensional' on 1 arguments at /proc/cygdrive/E/gap-4.10.0/lib/methsel2.g:250 called from
IsFiniteDimensional( V ) at /proc/cygdrive/E/gap-4.10.0/lib/modfree.gi:318     called from
<function "unknown">( <arguments> )
 called from read-eval loop at *stdin*:490
type 'quit;' to quit to outer loop
brk> quit;

gap> Zero(A);
Error, no method found! For debugging hints type ?Recovery from     NoMethodFound
Error, no 1st choice method found for `ZeroMutable' on 1 arguments at     /proc/cygdrive/E/gap-4.10.0/lib/methsel2.g:250 called from
ZERO_MUT( elm ) at /proc/cygdrive/E/gap-4.10.0/lib/arith.gi:79 called from
Zero( Representative( A ) ) at /proc/cygdrive/E/gap-    4.10.0/lib/addmagma.gi:605 called from
<function "unknown">( <arguments> )
 called from read-eval loop at *stdin*:490
type 'quit;' to quit to outer loop
brk> quit;