Consider the following premises. For all x_13, x_13 will make tea. There is at least one x_13 for which x_13 is curious or x_13 is a musician. For all x_13, if x_13 were a musician, then x_13 is a politician. For all x_13, x_13 is a politician if and only if x_13 is curious. Can we infer the following from them? If we can, name the inference rule being used: For all x_13, either x_13 is a politician or x_13 will make tea are not true.
 From the fact that for all x_13, x_13 is a politician if and only if x_13 is curious we can infer that for all x_13, if x_13 were curious, then x_13 is a politician via universal biconditional elimination. From the fact that for all x_13, if x_13 were curious, then x_13 is a politician, that for all x_13, if x_13 were a musician, then x_13 is a politician, and that there is at least one x_13 for which x_13 is curious or x_13 is a musician we can infer that there is at least one x_13 for which x_13 is a politician via existential disjunction elimination. Finally, from the fact that there is at least one x_13 for which x_13 is a politician, and that for all x_13, x_13 will make tea we can infer that some politicians will make tea via existential conjunction, which contradicts that For all x_13, either x_13 is a politician or x_13 will make tea are not true. Therefore, the answer is no.