What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_1, x_1 will not cook. There is at least one x_1 for which if x_1 writes a letter, then x_1 is cooking. For all x_1, x_1 is a sailor if and only if x_1 will write a letter.
There is at least one x_1 for which x_1 will not write a letter. For all x_1, if x_1 were a sailor, then x_1 is writing a letter. For all x_1, if x_1 writes a letter, then x_1 is a sailor.