Consider the following premises. u -> R_15(c). S_15(c) -> q_1. ~q_1. forall x_15: R_15(x_15) -> S_15(x_15). Can we infer u from them? If possible, name the inference rules being used at each step.
 From forall x_15: R_15(x_15) -> S_15(x_15) we can infer R_15(c) -> S_15(c) via universal instantiation. From u -> R_15(c), R_15(c) -> S_15(c) we can infer u -> S_15(c) via transitivity. From S_15(c) -> q_1, ~q_1 we can infer ~S_15(c) via modus tollens. Finally, from u -> S_15(c), ~S_15(c) we can infer ~u via modus tollens, which contradicts u. Therefore, the answer is no.