Recursively Enumerable Languages 

> P:=table():P[[S]]:={[a,A,b]}: P[[a,A]]:={[a,A,b],[\lambda]}:
csg:=UG({S,A},{a,b},S,op(P));
 

`:=`(csg, UG({S, A}, {a, b}, S, TABLE([[a, A] = {[a, A, b], [lambda]}, [S] = {[a, A, b]}]))) (15.1)
 

>