IsCyc( obj )
returns true if obj is a cyclotomic, and false otherwise. Will
signal an error if obj is an unbound variable.
gap> IsCyc( 0 ); IsCyc( E(3) ); IsCyc( 1/2 * E(3) ); IsCyc( IsCyc );
true
true
true
false
IsCyc is an internal function.
GAP 3.4.4