Consider the following premises. p_2 or u_3. forall z: S(z) -> S_4(z). ~p_2 or S(g_1). u_3 <-> S_4(g_1). Can we infer S_4(g_1) from them? If possible, name the inference rules being used at each step.
 From forall z: S(z) -> S_4(z) we can infer S(g_1) -> S_4(g_1) via universal instantiation. From u_3 <-> S_4(g_1) we can infer u_3 -> S_4(g_1) via biconditional elimination. From p_2 or u_3, ~p_2 or S(g_1) we can infer u_3 or S(g_1) via resolution. Finally, from u_3 -> S_4(g_1), S(g_1) -> S_4(g_1), u_3 or S(g_1) we can infer S_4(g_1) via disjunction elimination. Therefore, the answer is yes.