• Let Gexpr = (N, T, P, E),
where N = {E},
T = {(, ), id1, id2, …, idm, op1, op2, … opn},
P = { E ® (E), E ® id1, E ® id2, …, E ® idm,
E ® E op1 E, E ® E op2 E, …, E ® E opn E }
Note: id1, id2, …, idm are
identifiers,
op1, op2, … opn are different operators