What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_3, x_3 is a politician if and only if x_3 will read a book. For all x_3, x_3 is a sailor if and only if x_3 is a politician. For all x_3, x_3 is not a sailor.
For all x_3, if x_3 were a politician, then x_3 is reading a book can be inferred via the universal biconditional elimination rule. For all x_3, if x_3 were a sailor, then x_3 is a politician can be inferred via the universal biconditional elimination rule. For all x_3, if x_3 reads a book, then x_3 is a politician can be inferred via the universal biconditional elimination rule. For all x_3, if x_3 were a politician, then x_3 is a sailor can be inferred via the universal biconditional elimination rule. For all x_3, x_3 is not a politician can be inferred via the universal biconditional elimination rule.