Consider the following premises. For all x_6, x_6 is a lawyer if and only if x_6 is an artist. There is at least one x_6 for which x_6 will not listen to a song. For all x_6, x_6 will listen to a song if and only if x_6 is an artist. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_6 for which x_6 is not a lawyer.
 From the fact that for all x_6, x_6 will listen to a song if and only if x_6 is an artist, and that there is at least one x_6 for which x_6 will not listen to a song we can infer that there is at least one x_6 for which x_6 is not an artist via existential biconditional elimination. Finally, from the fact that for all x_6, x_6 is a lawyer if and only if x_6 is an artist, and that there is at least one x_6 for which x_6 is not an artist we can infer that there is at least one x_6 for which x_6 is not a lawyer via existential biconditional elimination. Therefore, the answer is yes.