Consider the following premises. For all x_8, x_8 is a bartender or x_8 is happy. For all x_8, x_8 is not a bartender. There is at least one x_8 for which x_8 is happy if and only if x_8 is an artist. Can we infer the following from them? If we can, name the inference rule being used: For all x_8, x_8 is not an artist.
 From the fact that there is at least one x_8 for which x_8 is happy if and only if x_8 is an artist we can infer that there is at least one x_8 for which if x_8 were happy, then x_8 is an artist via existential biconditional elimination. From the fact that for all x_8, x_8 is a bartender or x_8 is happy, and that for all x_8, x_8 is not a bartender we can infer that for all x_8, x_8 is happy via universal disjunctive syllogism. Finally, from the fact that there is at least one x_8 for which if x_8 were happy, then x_8 is an artist, and that for all x_8, x_8 is happy we can infer that there is at least one x_8 for which x_8 is an artist via existential modus ponens, which contradicts that For all x_8, x_8 is not an artist. Therefore, the answer is no.