Consider the following premises. For all x_8, x_8 is a poet if and only if x_8 will take a plane. For all x_8, x_8 is curious or x_8 will write a letter. For all x_8, x_8 will not take a plane. For all x_8, x_8 is a poet if and only if x_8 is curious. Can we infer the following from them? There is at least one x_8 for which x_8 will not write a letter.
 From the fact that for all x_8, x_8 is a poet if and only if x_8 will take a plane, and that for all x_8, x_8 will not take a plane we can infer that for all x_8, x_8 is not a poet. From the fact that for all x_8, x_8 is a poet if and only if x_8 is curious, and that for all x_8, x_8 is not a poet we can infer that for all x_8, x_8 is not curious. Finally, from the fact that for all x_8, x_8 is curious or x_8 will write a letter, and that for all x_8, x_8 is not curious we can infer that for all x_8, x_8 will write a letter, which contradicts that There is at least one x_8 for which x_8 will not write a letter. Therefore, the answer is no.