Consider the following premises. P_1(g). Can we infer exists y_4: P_1(y_4) or S(y_4) from them? If possible, name the inference rules being used at each step.
 From P_1(g) we can infer exists y_4: P_1(y_4) via existential generalization. Finally, from exists y_4: P_1(y_4) we can infer exists y_4: P_1(y_4) or S(y_4) via existential addition. Therefore, the answer is yes.